From 734cd9915926ab7a0ace0ef736aa09fd26046aea Mon Sep 17 00:00:00 2001
From: Alex Domingo <alex.domingo.toro@vub.be>
Date: Mon, 23 Sep 2024 16:43:43 +0200
Subject: [PATCH 01/21] refactor generation of required environment variables
 in module files

---
 easybuild/framework/easyblock.py | 146 ++++++++++++++-----------------
 easybuild/tools/config.py        |   5 +-
 2 files changed, 72 insertions(+), 79 deletions(-)

diff --git a/easybuild/framework/easyblock.py b/easybuild/framework/easyblock.py
index 88da255d1d..d2977cede4 100644
--- a/easybuild/framework/easyblock.py
+++ b/easybuild/framework/easyblock.py
@@ -74,6 +74,7 @@
 from easybuild.tools.build_log import print_error, print_msg, print_warning
 from easybuild.tools.config import CHECKSUM_PRIORITY_JSON, DEFAULT_ENVVAR_USERS_MODULES
 from easybuild.tools.config import FORCE_DOWNLOAD_ALL, FORCE_DOWNLOAD_PATCHES, FORCE_DOWNLOAD_SOURCES
+from easybuild.tools.config import SEARCH_PATH_BIN_DIRS, SEARCH_PATH_HEADER_DIRS, SEARCH_PATH_LIB_DIRS
 from easybuild.tools.config import EASYBUILD_SOURCES_URL # noqa
 from easybuild.tools.config import build_option, build_path, get_log_filename, get_repository, get_repositorypath
 from easybuild.tools.config import install_path, log_path, package_path, source_paths
@@ -107,10 +108,13 @@
 from easybuild.tools.utilities import remove_unwanted_chars, time2str, trace_msg
 from easybuild.tools.version import this_is_easybuild, VERBOSE_VERSION, VERSION
 
-DEFAULT_BIN_LIB_SUBDIRS = ('bin', 'lib', 'lib64')
+DEFAULT_BIN_LIB_SUBDIRS = SEARCH_PATH_BIN_DIRS + SEARCH_PATH_LIB_DIRS
 
 MODULE_ONLY_STEPS = [MODULE_STEP, PREPARE_STEP, READY_STEP, POSTITER_STEP, SANITYCHECK_STEP]
 
+# search paths that require some file in their top directory
+NON_RECURSIVE_SEARCH_PATHS = ["PATH", "LD_LIBRARY_PATH"]
+
 # string part of URL for Python packages on PyPI that indicates needs to be rewritten (see derive_alt_pypi_url)
 PYPI_PKG_URL_PATTERN = 'pypi.python.org/packages/source/'
 
@@ -1557,107 +1561,93 @@ def make_module_group_check(self):
 
     def make_module_req(self):
         """
-        Generate the environment-variables to run the module.
+        Generate the environment-variables required to run the module.
         """
-        requirements = self.make_module_req_guess()
-
-        lines = ['\n']
-        if os.path.isdir(self.installdir):
-            old_dir = change_dir(self.installdir)
-        else:
-            old_dir = None
+        mod_lines = ['\n']
 
         if self.dry_run:
             self.dry_run_msg("List of paths that would be searched and added to module file:\n")
             note = "note: glob patterns are not expanded and existence checks "
             note += "for paths are skipped for the statements below due to dry run"
-            lines.append(self.module_generator.comment(note))
-
-        # For these environment variables, the corresponding directory must include at least one file.
-        # The values determine if detection is done recursively, i.e. if it accepts directories where files
-        # are only in subdirectories.
-        keys_requiring_files = {
-            'PATH': False,
-            'LD_LIBRARY_PATH': False,
-            'LIBRARY_PATH': True,
-            'CPATH': True,
-            'CMAKE_PREFIX_PATH': True,
-            'CMAKE_LIBRARY_PATH': True,
-        }
+            mod_lines.append(self.module_generator.comment(note))
+
+        env_var_requirements = self.make_module_req_guess()
+        for env_var, search_paths in sorted(env_var_requirements.items()):
+            if isinstance(search_paths, str):
+                self.log.warning("Hoisting string value %s into a list before iterating over it", search_paths)
+                search_paths = [search_paths]
 
-        for key, reqs in sorted(requirements.items()):
-            if isinstance(reqs, str):
-                self.log.warning("Hoisting string value %s into a list before iterating over it", reqs)
-                reqs = [reqs]
+            mod_env_paths = []
+            recursive = env_var not in NON_RECURSIVE_SEARCH_PATHS
             if self.dry_run:
-                self.dry_run_msg(" $%s: %s" % (key, ', '.join(reqs)))
-                # Don't expand globs or do any filtering below for dry run
-                paths = reqs
+                self.dry_run_msg(f" ${env_var}:{', '.join(search_paths)}")
+                # Don't expand globs or do any filtering for dry run
+                mod_env_paths = search_paths
             else:
-                # Expand globs but only if the string is non-empty
-                # empty string is a valid value here (i.e. to prepend the installation prefix, cfr $CUDA_HOME)
-                paths = sum((glob.glob(path) if path else [path] for path in reqs), [])  # sum flattens to list
-
-                # If lib64 is just a symlink to lib we fixup the paths to avoid duplicates
-                lib64_is_symlink = (all(os.path.isdir(path) for path in ['lib', 'lib64']) and
-                                    os.path.samefile('lib', 'lib64'))
-                if lib64_is_symlink:
-                    fixed_paths = []
-                    for path in paths:
-                        if (path + os.path.sep).startswith('lib64' + os.path.sep):
-                            # We only need CMAKE_LIBRARY_PATH if there is a separate lib64 path, so skip symlink
-                            if key == 'CMAKE_LIBRARY_PATH':
-                                continue
-                            path = path.replace('lib64', 'lib', 1)
-                        fixed_paths.append(path)
-                    if fixed_paths != paths:
-                        self.log.info("Fixed symlink lib64 in paths for %s: %s -> %s", key, paths, fixed_paths)
-                        paths = fixed_paths
-                # remove duplicate paths preserving order
-                paths = nub(paths)
-                if key in keys_requiring_files:
-                    # only retain paths that contain at least one file
-                    recursive = keys_requiring_files[key]
-                    retained_paths = []
-                    for pth in paths:
-                        fullpath = os.path.join(self.installdir, pth)
-                        if os.path.isdir(fullpath) and dir_contains_files(fullpath, recursive=recursive):
-                            retained_paths.append(pth)
-                    if retained_paths != paths:
-                        self.log.info("Only retaining paths for %s that contain at least one file: %s -> %s",
-                                      key, paths, retained_paths)
-                        paths = retained_paths
-
-            if paths:
-                lines.append(self.module_generator.prepend_paths(key, paths))
+                for sp in search_paths:
+                    mod_env_paths.extend(self._expand_module_search_path(sp, recursive))
+
+            if mod_env_paths:
+                mod_env_paths = nub(mod_env_paths)  # remove duplicates
+                mod_lines.append(self.module_generator.prepend_paths(env_var, mod_env_paths))
+
         if self.dry_run:
             self.dry_run_msg('')
 
-        if old_dir is not None:
-            change_dir(old_dir)
-
-        return ''.join(lines)
+        return "".join(mod_lines)
 
     def make_module_req_guess(self):
         """
-        A dictionary of possible directories to look for.
+        A dictionary of common search path variables to be loaded by environment modules
+        Each key contains the list of known directories related to the search path
         """
-        lib_paths = ['lib', 'lib32', 'lib64']
         return {
-            'PATH': ['bin', 'sbin'],
-            'LD_LIBRARY_PATH': lib_paths,
-            'LIBRARY_PATH': lib_paths,
-            'CPATH': ['include'],
+            'PATH': SEARCH_PATH_BIN_DIRS + ['sbin'],
+            'LD_LIBRARY_PATH': SEARCH_PATH_LIB_DIRS,
+            'LIBRARY_PATH': SEARCH_PATH_LIB_DIRS,
+            'CPATH': SEARCH_PATH_HEADER_DIRS,
             'MANPATH': ['man', os.path.join('share', 'man')],
-            'PKG_CONFIG_PATH': [os.path.join(x, 'pkgconfig') for x in lib_paths + ['share']],
+            'PKG_CONFIG_PATH': [os.path.join(x, 'pkgconfig') for x in SEARCH_PATH_LIB_DIRS + ['share']],
             'ACLOCAL_PATH': [os.path.join('share', 'aclocal')],
             'CLASSPATH': ['*.jar'],
             'XDG_DATA_DIRS': ['share'],
-            'GI_TYPELIB_PATH': [os.path.join(x, 'girepository-*') for x in lib_paths],
+            'GI_TYPELIB_PATH': [os.path.join(x, 'girepository-*') for x in SEARCH_PATH_LIB_DIRS],
             'CMAKE_PREFIX_PATH': [''],
-            'CMAKE_LIBRARY_PATH': ['lib64'],  # lib and lib32 are searched through the above
+            'CMAKE_LIBRARY_PATH': ['lib64'],  # only needed for installations whith standalone lib64
         }
 
+    def _expand_module_search_path(self, search_path, recursive):
+        """
+        Expand given path glob and return list of paths that are suitable to be
+        used as search paths in environment module
+        """
+        # Expand globs but only if the string is non-empty
+        # empty string is a valid value here (i.e. to prepend the installation prefix root directory)
+        abs_search_path = os.path.join(self.installdir, search_path)
+        exp_search_paths = [abs_search_path] if search_path == "" else glob.glob(abs_search_path)
+
+        retained_search_paths = []
+        for abs_path in exp_search_paths:
+            tentative_path = os.path.relpath(abs_path, start=self.installdir)
+            tentative_path = "" if tentative_path == "." else tentative_path  # use empty string instead of dot
+
+            # avoid duplicate entries if lib64 is just a symlink to lib
+            if (tentative_path + os.path.sep).startswith("lib64" + os.path.sep):
+                abs_lib_path = os.path.join(self.installdir, "lib")
+                abs_lib64_path = os.path.join(self.installdir, "lib64")
+                if os.path.islink(abs_lib64_path) and os.path.samefile(abs_lib_path, abs_lib64_path):
+                    self.log.debug("Discarded search path to symlink lib64: %s", tentative_path)
+                    break
+
+            # only retain paths to directories that contain at least one file
+            if os.path.isdir(abs_path) and not dir_contains_files(abs_path, recursive=recursive):
+                self.log.debug("Discarded search path to empty directory: %s", tentative_path)
+                break
+
+            retained_search_paths.append(tentative_path)
+
+        return retained_search_paths
+
     def load_module(self, mod_paths=None, purge=True, extra_modules=None, verbose=True):
         """
         Load module for this software package/version, after purging all currently loaded modules.
diff --git a/easybuild/tools/config.py b/easybuild/tools/config.py
index 13f9722bce..c9a914d478 100644
--- a/easybuild/tools/config.py
+++ b/easybuild/tools/config.py
@@ -168,13 +168,16 @@
 LOCAL_VAR_NAMING_CHECK_WARN = WARN
 LOCAL_VAR_NAMING_CHECKS = [LOCAL_VAR_NAMING_CHECK_ERROR, LOCAL_VAR_NAMING_CHECK_LOG, LOCAL_VAR_NAMING_CHECK_WARN]
 
-
 OUTPUT_STYLE_AUTO = 'auto'
 OUTPUT_STYLE_BASIC = 'basic'
 OUTPUT_STYLE_NO_COLOR = 'no_color'
 OUTPUT_STYLE_RICH = 'rich'
 OUTPUT_STYLES = (OUTPUT_STYLE_AUTO, OUTPUT_STYLE_BASIC, OUTPUT_STYLE_NO_COLOR, OUTPUT_STYLE_RICH)
 
+SEARCH_PATH_BIN_DIRS = ["bin"]
+SEARCH_PATH_HEADER_DIRS = ["include"]
+SEARCH_PATH_LIB_DIRS = ["lib", "lib64"]
+
 
 class Singleton(ABCMeta):
     """Serves as metaclass for classes that should implement the Singleton pattern.

From df505cf7da212f6d81dd3ca1933789c5fe64e6bc Mon Sep 17 00:00:00 2001
From: Alex Domingo <alex.domingo.toro@vub.be>
Date: Mon, 23 Sep 2024 16:45:08 +0200
Subject: [PATCH 02/21] update test_make_module_req to add a file into MANPATH
 of test installation

---
 test/framework/easyblock.py | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/test/framework/easyblock.py b/test/framework/easyblock.py
index 505a1c1d2f..bdf15504f4 100644
--- a/test/framework/easyblock.py
+++ b/test/framework/easyblock.py
@@ -433,12 +433,13 @@ def test_make_module_req(self):
 
         # create fake directories and files that should be guessed
         os.makedirs(eb.installdir)
-        write_file(os.path.join(eb.installdir, 'foo.jar'), 'foo.jar')
-        write_file(os.path.join(eb.installdir, 'bla.jar'), 'bla.jar')
         for path in ('bin', ('bin', 'testdir'), 'sbin', 'share', ('share', 'man'), 'lib', 'lib64'):
             if isinstance(path, str):
                 path = (path, )
             os.mkdir(os.path.join(eb.installdir, *path))
+        write_file(os.path.join(eb.installdir, 'foo.jar'), 'foo.jar')
+        write_file(os.path.join(eb.installdir, 'bla.jar'), 'bla.jar')
+        write_file(os.path.join(eb.installdir, 'share', 'man', 'pi'), 'Man page')
         # this is not a path that should be picked up
         os.mkdir(os.path.join(eb.installdir, 'CPATH'))
 

From 56800386935a56b23bb024c104d4c209a0a4d31f Mon Sep 17 00:00:00 2001
From: Alex Domingo <alex.domingo.toro@vub.be>
Date: Tue, 24 Sep 2024 01:58:59 +0200
Subject: [PATCH 03/21] disable non-empty check on search path drectories for
 fake module files

---
 easybuild/framework/easyblock.py | 18 +++++++++++-------
 1 file changed, 11 insertions(+), 7 deletions(-)

diff --git a/easybuild/framework/easyblock.py b/easybuild/framework/easyblock.py
index d2977cede4..559c6630df 100644
--- a/easybuild/framework/easyblock.py
+++ b/easybuild/framework/easyblock.py
@@ -1559,9 +1559,10 @@ def make_module_group_check(self):
 
         return txt
 
-    def make_module_req(self):
+    def make_module_req(self, fake=False):
         """
         Generate the environment-variables required to run the module.
+        Fake modules can set search paths to empty directories.
         """
         mod_lines = ['\n']
 
@@ -1585,7 +1586,7 @@ def make_module_req(self):
                 mod_env_paths = search_paths
             else:
                 for sp in search_paths:
-                    mod_env_paths.extend(self._expand_module_search_path(sp, recursive))
+                    mod_env_paths.extend(self._expand_module_search_path(sp, recursive, fake=fake))
 
             if mod_env_paths:
                 mod_env_paths = nub(mod_env_paths)  # remove duplicates
@@ -1616,10 +1617,12 @@ def make_module_req_guess(self):
             'CMAKE_LIBRARY_PATH': ['lib64'],  # only needed for installations whith standalone lib64
         }
 
-    def _expand_module_search_path(self, search_path, recursive):
+    def _expand_module_search_path(self, search_path, recursive, fake=False):
         """
-        Expand given path glob and return list of paths that are suitable to be
-        used as search paths in environment module
+        Expand given path glob and return list of suitable paths to be used as search paths:
+            - Files must exist and directories be non-empty
+            - Fake modules can set search paths to empty directories
+            - Search paths to 'lib64' symlinked to 'lib' are discarded
         """
         # Expand globs but only if the string is non-empty
         # empty string is a valid value here (i.e. to prepend the installation prefix root directory)
@@ -1628,6 +1631,7 @@ def _expand_module_search_path(self, search_path, recursive):
 
         retained_search_paths = []
         for abs_path in exp_search_paths:
+            # return relative paths
             tentative_path = os.path.relpath(abs_path, start=self.installdir)
             tentative_path = "" if tentative_path == "." else tentative_path  # use empty string instead of dot
 
@@ -1640,7 +1644,7 @@ def _expand_module_search_path(self, search_path, recursive):
                     break
 
             # only retain paths to directories that contain at least one file
-            if os.path.isdir(abs_path) and not dir_contains_files(abs_path, recursive=recursive):
+            if os.path.isdir(abs_path) and not dir_contains_files(abs_path, recursive=recursive) and not fake:
                 self.log.debug("Discarded search path to empty directory: %s", tentative_path)
                 break
 
@@ -3785,7 +3789,7 @@ def make_module_step(self, fake=False):
             txt += self.make_module_deppaths()
             txt += self.make_module_dep()
             txt += self.make_module_extend_modpath()
-            txt += self.make_module_req()
+            txt += self.make_module_req(fake=fake)
             txt += self.make_module_extra()
             txt += self.make_module_footer()
 

From 5b17f2e8e85b0abd822c70c792db253074dc7e70 Mon Sep 17 00:00:00 2001
From: Alex Domingo <alex.domingo.toro@vub.be>
Date: Tue, 24 Sep 2024 23:17:18 +0200
Subject: [PATCH 04/21] change position of easyblock methods
 make_module_req_guess and _expand_module_search_path

---
 easybuild/framework/easyblock.py | 40 ++++++++++++++++----------------
 1 file changed, 20 insertions(+), 20 deletions(-)

diff --git a/easybuild/framework/easyblock.py b/easybuild/framework/easyblock.py
index 559c6630df..660af36ccf 100644
--- a/easybuild/framework/easyblock.py
+++ b/easybuild/framework/easyblock.py
@@ -1597,26 +1597,6 @@ def make_module_req(self, fake=False):
 
         return "".join(mod_lines)
 
-    def make_module_req_guess(self):
-        """
-        A dictionary of common search path variables to be loaded by environment modules
-        Each key contains the list of known directories related to the search path
-        """
-        return {
-            'PATH': SEARCH_PATH_BIN_DIRS + ['sbin'],
-            'LD_LIBRARY_PATH': SEARCH_PATH_LIB_DIRS,
-            'LIBRARY_PATH': SEARCH_PATH_LIB_DIRS,
-            'CPATH': SEARCH_PATH_HEADER_DIRS,
-            'MANPATH': ['man', os.path.join('share', 'man')],
-            'PKG_CONFIG_PATH': [os.path.join(x, 'pkgconfig') for x in SEARCH_PATH_LIB_DIRS + ['share']],
-            'ACLOCAL_PATH': [os.path.join('share', 'aclocal')],
-            'CLASSPATH': ['*.jar'],
-            'XDG_DATA_DIRS': ['share'],
-            'GI_TYPELIB_PATH': [os.path.join(x, 'girepository-*') for x in SEARCH_PATH_LIB_DIRS],
-            'CMAKE_PREFIX_PATH': [''],
-            'CMAKE_LIBRARY_PATH': ['lib64'],  # only needed for installations whith standalone lib64
-        }
-
     def _expand_module_search_path(self, search_path, recursive, fake=False):
         """
         Expand given path glob and return list of suitable paths to be used as search paths:
@@ -1652,6 +1632,26 @@ def _expand_module_search_path(self, search_path, recursive, fake=False):
 
         return retained_search_paths
 
+    def make_module_req_guess(self):
+        """
+        A dictionary of common search path variables to be loaded by environment modules
+        Each key contains the list of known directories related to the search path
+        """
+        return {
+            'PATH': SEARCH_PATH_BIN_DIRS + ['sbin'],
+            'LD_LIBRARY_PATH': SEARCH_PATH_LIB_DIRS,
+            'LIBRARY_PATH': SEARCH_PATH_LIB_DIRS,
+            'CPATH': SEARCH_PATH_HEADER_DIRS,
+            'MANPATH': ['man', os.path.join('share', 'man')],
+            'PKG_CONFIG_PATH': [os.path.join(x, 'pkgconfig') for x in SEARCH_PATH_LIB_DIRS + ['share']],
+            'ACLOCAL_PATH': [os.path.join('share', 'aclocal')],
+            'CLASSPATH': ['*.jar'],
+            'XDG_DATA_DIRS': ['share'],
+            'GI_TYPELIB_PATH': [os.path.join(x, 'girepository-*') for x in SEARCH_PATH_LIB_DIRS],
+            'CMAKE_PREFIX_PATH': [''],
+            'CMAKE_LIBRARY_PATH': ['lib64'],  # only needed for installations whith standalone lib64
+        }
+
     def load_module(self, mod_paths=None, purge=True, extra_modules=None, verbose=True):
         """
         Load module for this software package/version, after purging all currently loaded modules.

From 9205c3b5731d4b678d68b5904ee62eed6703253f Mon Sep 17 00:00:00 2001
From: Alex Domingo <alex.domingo.toro@vub.be>
Date: Tue, 1 Oct 2024 00:03:31 +0200
Subject: [PATCH 05/21] add new class ModuleEnvironmentVariable to hold
 definitions of environment variables for module files

---
 easybuild/tools/modules.py | 36 ++++++++++++++++++++++++++++++++++++
 test/framework/modules.py  | 26 ++++++++++++++++++++++++++
 2 files changed, 62 insertions(+)

diff --git a/easybuild/tools/modules.py b/easybuild/tools/modules.py
index a4e1f565ae..e4699941de 100644
--- a/easybuild/tools/modules.py
+++ b/easybuild/tools/modules.py
@@ -130,6 +130,42 @@
 
 _log = fancylogger.getLogger('modules', fname=False)
 
+class ModuleEnvironmentVariable:
+    """Environment variable data structure for modules"""
+    def __init__(self, paths, empty=False, top_level_file=False):
+        self.paths = paths
+        self.empty = bool(empty)
+        self.top_level_file = bool(top_level_file)
+
+    def __str__(self):
+        return ":".join(self.paths)
+
+    @property
+    def paths(self):
+        return self._paths
+
+    @paths.setter
+    def paths(self, value):
+        """Enforce that paths is a list of strings"""
+        if isinstance(value, str):
+            value = [value]
+        try:
+            self._paths = [str(path) for path in value]
+        except TypeError:
+            raise TypeError("ModuleEnvironmentVariable.paths must be a list of strings") from None
+
+    def append(self, *args):
+        """Shortcut to append to list of paths"""
+        self.paths.append(*args)
+
+    def extend(self, *args):
+        """Shortcut to extend list of paths"""
+        self.paths.extend(*args)
+
+    def prepend(self, item):
+        """Shortcut to append to list of paths"""
+        self.paths.insert(0, item)
+
 
 class ModulesTool(object):
     """An abstract interface to a tool that deals with modules."""
diff --git a/test/framework/modules.py b/test/framework/modules.py
index 5cd783694d..1d847db6b1 100644
--- a/test/framework/modules.py
+++ b/test/framework/modules.py
@@ -1588,6 +1588,32 @@ def test_get_setenv_value_from_modulefile(self):
         res = self.modtool.get_setenv_value_from_modulefile('toy/0.0', 'NO_SUCH_VARIABLE_SET')
         self.assertEqual(res, None)
 
+    def test_module_environment_variable(self):
+        """Test for ModuleEnvironmentVariable object"""
+        test_paths = ['lib', 'lib64']
+        mod_envar = mod.ModuleEnvironmentVariable(test_paths)
+        self.assertTrue(hasattr(mod_envar, "paths"))
+        self.assertTrue(hasattr(mod_envar, "empty"))
+        self.assertTrue(hasattr(mod_envar, "top_level_file"))
+        self.assertEqual(mod_envar.paths, test_paths)
+        self.assertEqual(str(mod_envar), "lib:lib64")
+
+        mod_envar.paths = []
+        self.assertEqual(mod_envar.paths, [])
+        self.assertRaises(TypeError, setattr, mod_envar, "paths", None)
+
+        mod_envar.paths = (1, 2, 3)
+        self.assertEqual(mod_envar.paths, ["1", "2", "3"])
+
+        mod_envar.paths = "include"
+        self.assertEqual(mod_envar.paths, ["include"])
+
+        mod_envar.append("share")
+        self.assertEqual(mod_envar.paths, ["include", "share"])
+        mod_envar.extend(test_paths)
+        self.assertEqual(mod_envar.paths, ["include", "share", "lib", "lib64"])
+        mod_envar.prepend("bin")
+        self.assertEqual(mod_envar.paths, ["bin", "include", "share", "lib", "lib64"])
 
 def suite():
     """ returns all the testcases in this module """

From 29affc984bda000780fc6f8b91d83c2d519eb1bb Mon Sep 17 00:00:00 2001
From: Alex Domingo <alex.domingo.toro@vub.be>
Date: Tue, 1 Oct 2024 00:05:06 +0200
Subject: [PATCH 06/21] add new class ModuleLoadEnvironment to hold environment
 definition for modules on load

---
 easybuild/tools/modules.py | 84 +++++++++++++++++++++++++++++++++++++-
 test/framework/modules.py  | 21 ++++++++++
 2 files changed, 104 insertions(+), 1 deletion(-)

diff --git a/easybuild/tools/modules.py b/easybuild/tools/modules.py
index e4699941de..5bef0e82bb 100644
--- a/easybuild/tools/modules.py
+++ b/easybuild/tools/modules.py
@@ -43,11 +43,13 @@
 import shlex
 
 from easybuild.base import fancylogger
+from easybuild.base.wrapper import create_base_metaclass
 from easybuild.tools import LooseVersion
 from easybuild.tools.build_log import EasyBuildError, EasyBuildExit, print_warning
 from easybuild.tools.config import ERROR, IGNORE, PURGE, UNLOAD, UNSET
 from easybuild.tools.config import EBROOT_ENV_VAR_ACTIONS, LOADED_MODULES_ACTIONS
-from easybuild.tools.config import build_option, get_modules_tool, install_path
+from easybuild.tools.config import Singleton, build_option, get_modules_tool, install_path
+from easybuild.tools.config import SEARCH_PATH_BIN_DIRS, SEARCH_PATH_HEADER_DIRS, SEARCH_PATH_LIB_DIRS
 from easybuild.tools.environment import ORIG_OS_ENVIRON, restore_env, setvar, unset_env_vars
 from easybuild.tools.filetools import convert_name, mkdir, normalize_path, path_matches, read_file, which, write_file
 from easybuild.tools.module_naming_scheme.mns import DEVEL_MODULE_SUFFIX
@@ -167,6 +169,86 @@ def prepend(self, item):
         self.paths.insert(0, item)
 
 
+# singleton metaclass: only one instance is created
+BaseModuleEnvironment = create_base_metaclass('BaseModuleEnvironment', Singleton, object)
+
+
+class ModuleLoadEnvironment(BaseModuleEnvironment):
+    """Environment set by modules on load"""
+
+    def __init__(self):
+        """
+        Initialize default environment definition
+        Paths are relative to root of installation directory
+        """
+
+        self.PATH = ModuleEnvironmentVariable(
+            SEARCH_PATH_BIN_DIRS + ['sbin'],
+            top_level_file=True,
+        )
+        self.LD_LIBRARY_PATH = ModuleEnvironmentVariable(
+            SEARCH_PATH_LIB_DIRS,
+            top_level_file=True,
+        )
+        self.LIBRARY_PATH = ModuleEnvironmentVariable(
+            SEARCH_PATH_LIB_DIRS,
+        )
+        self.CPATH = ModuleEnvironmentVariable(
+            SEARCH_PATH_HEADER_DIRS,
+        )
+        self.MANPATH = ModuleEnvironmentVariable(
+            ['man', os.path.join('share', 'man')],
+        )
+        self.PKG_CONFIG_PATH = ModuleEnvironmentVariable(
+            [os.path.join(x, 'pkgconfig') for x in SEARCH_PATH_LIB_DIRS + ['share']],
+        )
+        self.ACLOCAL_PATH = ModuleEnvironmentVariable(
+            [os.path.join('share', 'aclocal')],
+        )
+        self.CLASSPATH = ModuleEnvironmentVariable(
+            ['*.jar'],
+        )
+        self.XDG_DATA_DIRS = ModuleEnvironmentVariable(
+            ['share'],
+        )
+        self.GI_TYPELIB_PATH = ModuleEnvironmentVariable(
+            [os.path.join(x, 'girepository-*') for x in SEARCH_PATH_LIB_DIRS]
+        )
+        self.CMAKE_PREFIX_PATH = ModuleEnvironmentVariable(
+            [''],
+        )
+        # only needed for installations whith standalone lib64
+        self.CMAKE_LIBRARY_PATH = ModuleEnvironmentVariable(
+            ['lib64'],
+        )
+
+    def __iter__(self):
+        """Make the class iterable"""
+        yield from (envar for envar in self.__dict__ if isinstance(getattr(self, envar), ModuleEnvironmentVariable))
+
+    def items(self):
+        """
+        Return key-value pairs for each attribute that is a ModuleEnvironmentVariable
+        - key = attribute name
+        - value = its "paths" attribute
+        """
+        for attr in self.__dict__:
+            envar = getattr(self, attr)
+            if isinstance(envar, ModuleEnvironmentVariable):
+                yield attr, envar.paths
+
+    @property
+    def environ(self):
+        """
+        Return dict with mapping of ModuleEnvironmentVariables names with their paths
+        Equivalent in shape to os.environ
+        """
+        mapping = {}
+        for envar_name, envar_paths in self.items():
+            mapping.update({envar_name: envar_paths})
+        return mapping
+
+
 class ModulesTool(object):
     """An abstract interface to a tool that deals with modules."""
     # name of this modules tool (used in log/warning/error messages)
diff --git a/test/framework/modules.py b/test/framework/modules.py
index 1d847db6b1..4437360359 100644
--- a/test/framework/modules.py
+++ b/test/framework/modules.py
@@ -1615,6 +1615,27 @@ def test_module_environment_variable(self):
         mod_envar.prepend("bin")
         self.assertEqual(mod_envar.paths, ["bin", "include", "share", "lib", "lib64"])
 
+    def test_module_load_environment(self):
+        """Test for ModuleLoadEnvironment object"""
+        mod_load_env = mod.ModuleLoadEnvironment()
+        mod_load_env.TEST_VAR = mod.ModuleEnvironmentVariable(["lib", "lib64"])
+        self.assertTrue(hasattr(mod_load_env, "TEST_VAR"))
+        self.assertEqual(mod_load_env.TEST_VAR.paths, ["lib", "lib64"])
+
+        # copy current state as reference
+        ref_load_env = mod_load_env.__dict__.copy()
+        # and add some garbage
+        mod_load_env.garbage = "not_an_env_var"
+        self.assertTrue(hasattr(mod_load_env, "garbage"))
+        self.assertEqual(mod_load_env.garbage, "not_an_env_var")
+
+        self.assertCountEqual(list(mod_load_env), ref_load_env.keys())
+        ref_load_env_item_list = [(key, value.paths) for key, value in ref_load_env.items()]
+        self.assertCountEqual(list(mod_load_env.items()), ref_load_env_item_list)
+        ref_load_env_environ = {key: value.paths for key, value in ref_load_env.items()}
+        self.assertDictEqual(mod_load_env.environ, ref_load_env_environ)
+
+
 def suite():
     """ returns all the testcases in this module """
     return TestLoaderFiltered().loadTestsFromTestCase(ModulesTest, sys.argv[1:])

From 8d3a0511dc9dac7f6dee1d69d2e8104234142fed Mon Sep 17 00:00:00 2001
From: Alex Domingo <alex.domingo.toro@vub.be>
Date: Tue, 1 Oct 2024 00:06:43 +0200
Subject: [PATCH 07/21] add LibSymlink enum to easyblock to define possible
 states of symlinked library directories

---
 easybuild/framework/easyblock.py | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/easybuild/framework/easyblock.py b/easybuild/framework/easyblock.py
index 660af36ccf..3c13b45866 100644
--- a/easybuild/framework/easyblock.py
+++ b/easybuild/framework/easyblock.py
@@ -54,6 +54,7 @@
 import traceback
 from concurrent.futures import ThreadPoolExecutor
 from datetime import datetime
+from enum import Enum
 from textwrap import indent
 
 import easybuild.tools.environment as env
@@ -124,6 +125,11 @@
 _log = fancylogger.getLogger('easyblock')
 
 
+class LibSymlink(Enum):
+    """Possible states for symlinking of library directories"""
+    NONE, LIB, LIB64, NEITHER = range(0, 4)
+
+
 class EasyBlock(object):
     """Generic support for building and installing software, base class for actual easyblocks."""
 

From ee37ae744b930dda932ea7a60cf11aa650b2ce27 Mon Sep 17 00:00:00 2001
From: Alex Domingo <alex.domingo.toro@vub.be>
Date: Tue, 1 Oct 2024 00:07:30 +0200
Subject: [PATCH 08/21] set library symlink state at the end of
 post_install_step

---
 easybuild/framework/easyblock.py | 27 ++++++++++++++++++---------
 1 file changed, 18 insertions(+), 9 deletions(-)

diff --git a/easybuild/framework/easyblock.py b/easybuild/framework/easyblock.py
index 3c13b45866..a267cc86c1 100644
--- a/easybuild/framework/easyblock.py
+++ b/easybuild/framework/easyblock.py
@@ -214,6 +214,9 @@ def __init__(self, ec):
         # determine install subdirectory, based on module name
         self.install_subdir = None
 
+        # track status of symlink between library directories
+        self.install_lib_symlink = LibSymlink.NONE
+
         # indicates whether build should be performed in installation dir
         self.build_in_installdir = self.cfg['buildininstalldir']
 
@@ -3059,18 +3062,24 @@ def post_install_step(self):
         # However for each <dir> in $LIBRARY_PATH (where <dir> is often <prefix>/lib) it searches <dir>/../lib64 first.
         # So we create <prefix>/lib64 as a symlink to <prefix>/lib to make it prefer EB installed libraries.
         # See https://github.com/easybuilders/easybuild-easyconfigs/issues/5776
-        if build_option('lib64_lib_symlink'):
-            if os.path.exists(lib_dir) and not os.path.exists(lib64_dir):
-                # create *relative* 'lib64' symlink to 'lib';
-                # see https://github.com/easybuilders/easybuild-framework/issues/3564
-                symlink('lib', lib64_dir, use_abspath_source=False)
+        if build_option('lib64_lib_symlink') and os.path.exists(lib_dir) and not os.path.exists(lib64_dir):
+            # create *relative* 'lib64' symlink to 'lib';
+            # see https://github.com/easybuilders/easybuild-framework/issues/3564
+            symlink('lib', lib64_dir, use_abspath_source=False)
 
         # symlink lib to lib64, which is helpful on OpenSUSE;
         # see https://github.com/easybuilders/easybuild-framework/issues/3549
-        if build_option('lib_lib64_symlink'):
-            if os.path.exists(lib64_dir) and not os.path.exists(lib_dir):
-                # create *relative* 'lib' symlink to 'lib64';
-                symlink('lib64', lib_dir, use_abspath_source=False)
+        if build_option('lib_lib64_symlink') and os.path.exists(lib64_dir) and not os.path.exists(lib_dir):
+            # create *relative* 'lib' symlink to 'lib64';
+            symlink('lib64', lib_dir, use_abspath_source=False)
+
+        # check symlink state
+        if os.path.exists(lib_dir) and os.path.exists(lib64_dir):
+            self.install_lib_symlink = LibSymlink.NEITHER
+            if os.path.islink(lib_dir) and os.path.samefile(lib_dir, lib64_dir):
+                self.install_lib_symlink = LibSymlink.LIB
+            elif os.path.islink(lib64_dir) and os.path.samefile(lib_dir, lib64_dir):
+                self.install_lib_symlink = LibSymlink.LIB64
 
         self.run_post_install_commands()
         self.apply_post_install_patches()

From b6e1821d38637a202a7aa214e34b98bd60dcd7b7 Mon Sep 17 00:00:00 2001
From: Alex Domingo <alex.domingo.toro@vub.be>
Date: Tue, 1 Oct 2024 00:10:37 +0200
Subject: [PATCH 09/21] use environment definition from ModuleLoadEnvironment
 in make_module_req_guess

---
 easybuild/framework/easyblock.py | 21 ++++++---------------
 1 file changed, 6 insertions(+), 15 deletions(-)

diff --git a/easybuild/framework/easyblock.py b/easybuild/framework/easyblock.py
index a267cc86c1..afef6c2c53 100644
--- a/easybuild/framework/easyblock.py
+++ b/easybuild/framework/easyblock.py
@@ -97,7 +97,8 @@
 from easybuild.tools.module_generator import ModuleGeneratorLua, ModuleGeneratorTcl, module_generator, dependencies_for
 from easybuild.tools.module_naming_scheme.utilities import det_full_ec_version
 from easybuild.tools.modules import ROOT_ENV_VAR_NAME_PREFIX, VERSION_ENV_VAR_NAME_PREFIX, DEVEL_ENV_VAR_NAME_PREFIX
-from easybuild.tools.modules import Lmod, curr_module_paths, invalidate_module_caches_for, get_software_root
+from easybuild.tools.modules import Lmod, ModuleLoadEnvironment
+from easybuild.tools.modules import curr_module_paths, invalidate_module_caches_for, get_software_root
 from easybuild.tools.modules import get_software_root_env_var_name, get_software_version_env_var_name
 from easybuild.tools.output import PROGRESS_BAR_DOWNLOAD_ALL, PROGRESS_BAR_EASYCONFIG, PROGRESS_BAR_EXTENSIONS
 from easybuild.tools.output import show_progress_bars, start_progress_bar, stop_progress_bar, update_progress_bar
@@ -211,6 +212,9 @@ def __init__(self, ec):
         if modules_header_path is not None:
             self.modules_header = read_file(modules_header_path)
 
+        # environment variables on module load
+        self.module_load_environment = ModuleLoadEnvironment()
+
         # determine install subdirectory, based on module name
         self.install_subdir = None
 
@@ -1646,20 +1650,7 @@ def make_module_req_guess(self):
         A dictionary of common search path variables to be loaded by environment modules
         Each key contains the list of known directories related to the search path
         """
-        return {
-            'PATH': SEARCH_PATH_BIN_DIRS + ['sbin'],
-            'LD_LIBRARY_PATH': SEARCH_PATH_LIB_DIRS,
-            'LIBRARY_PATH': SEARCH_PATH_LIB_DIRS,
-            'CPATH': SEARCH_PATH_HEADER_DIRS,
-            'MANPATH': ['man', os.path.join('share', 'man')],
-            'PKG_CONFIG_PATH': [os.path.join(x, 'pkgconfig') for x in SEARCH_PATH_LIB_DIRS + ['share']],
-            'ACLOCAL_PATH': [os.path.join('share', 'aclocal')],
-            'CLASSPATH': ['*.jar'],
-            'XDG_DATA_DIRS': ['share'],
-            'GI_TYPELIB_PATH': [os.path.join(x, 'girepository-*') for x in SEARCH_PATH_LIB_DIRS],
-            'CMAKE_PREFIX_PATH': [''],
-            'CMAKE_LIBRARY_PATH': ['lib64'],  # only needed for installations whith standalone lib64
-        }
+        return self.module_load_environment.environ
 
     def load_module(self, mod_paths=None, purge=True, extra_modules=None, verbose=True):
         """

From 544a3165ba22f340f53c976495d767f9e075d1a7 Mon Sep 17 00:00:00 2001
From: Alex Domingo <alex.domingo.toro@vub.be>
Date: Tue, 1 Oct 2024 00:12:27 +0200
Subject: [PATCH 10/21] deprecate make_module_req_guess in favor of directly
 using ModuleLoadEnvironment

---
 easybuild/framework/easyblock.py | 44 +++++++++++++++++++-------------
 1 file changed, 26 insertions(+), 18 deletions(-)

diff --git a/easybuild/framework/easyblock.py b/easybuild/framework/easyblock.py
index afef6c2c53..5a27fae724 100644
--- a/easybuild/framework/easyblock.py
+++ b/easybuild/framework/easyblock.py
@@ -75,7 +75,7 @@
 from easybuild.tools.build_log import print_error, print_msg, print_warning
 from easybuild.tools.config import CHECKSUM_PRIORITY_JSON, DEFAULT_ENVVAR_USERS_MODULES
 from easybuild.tools.config import FORCE_DOWNLOAD_ALL, FORCE_DOWNLOAD_PATCHES, FORCE_DOWNLOAD_SOURCES
-from easybuild.tools.config import SEARCH_PATH_BIN_DIRS, SEARCH_PATH_HEADER_DIRS, SEARCH_PATH_LIB_DIRS
+from easybuild.tools.config import SEARCH_PATH_BIN_DIRS, SEARCH_PATH_LIB_DIRS
 from easybuild.tools.config import EASYBUILD_SOURCES_URL # noqa
 from easybuild.tools.config import build_option, build_path, get_log_filename, get_repository, get_repositorypath
 from easybuild.tools.config import install_path, log_path, package_path, source_paths
@@ -114,9 +114,6 @@
 
 MODULE_ONLY_STEPS = [MODULE_STEP, PREPARE_STEP, READY_STEP, POSTITER_STEP, SANITYCHECK_STEP]
 
-# search paths that require some file in their top directory
-NON_RECURSIVE_SEARCH_PATHS = ["PATH", "LD_LIBRARY_PATH"]
-
 # string part of URL for Python packages on PyPI that indicates needs to be rewritten (see derive_alt_pypi_url)
 PYPI_PKG_URL_PATTERN = 'pypi.python.org/packages/source/'
 
@@ -1585,25 +1582,36 @@ def make_module_req(self, fake=False):
             note += "for paths are skipped for the statements below due to dry run"
             mod_lines.append(self.module_generator.comment(note))
 
-        env_var_requirements = self.make_module_req_guess()
-        for env_var, search_paths in sorted(env_var_requirements.items()):
-            if isinstance(search_paths, str):
-                self.log.warning("Hoisting string value %s into a list before iterating over it", search_paths)
-                search_paths = [search_paths]
+        # prefer deprecated make_module_req_guess on custom easyblocks
+        if self.make_module_req_guess.__qualname__ == "EasyBlock.make_module_req_guess":
+            # No custom method in child Easyblock, deprecated method is defined by base EasyBlock class
+            env_var_requirements = self.module_load_environment.environ
+        else:
+            # Custom deprecated method used by child EasyBlock
+            self.log.devel(
+                "make_module_req_guess() is deprecated, use module_load_environment object instead.",
+                "6.0",
+            )
+            env_var_requirements = self.make_module_req_guess()
+            # backward compatibility: manually convert paths defined as string to lists
+            env_var_requirements.update({
+                envar: [path] for envar, path in env_var_requirements.items() if isinstance(path, str)
+            })
 
-            mod_env_paths = []
-            recursive = env_var not in NON_RECURSIVE_SEARCH_PATHS
+        for env_var, search_paths in sorted(env_var_requirements.items()):
             if self.dry_run:
                 self.dry_run_msg(f" ${env_var}:{', '.join(search_paths)}")
                 # Don't expand globs or do any filtering for dry run
-                mod_env_paths = search_paths
+                mod_req_paths = search_paths
             else:
-                for sp in search_paths:
-                    mod_env_paths.extend(self._expand_module_search_path(sp, recursive, fake=fake))
-
-            if mod_env_paths:
-                mod_env_paths = nub(mod_env_paths)  # remove duplicates
-                mod_lines.append(self.module_generator.prepend_paths(env_var, mod_env_paths))
+                mod_req_paths = []
+                top_level = getattr(self.module_load_environment, env_var).top_level_file
+                for path in search_paths:
+                    mod_req_paths.extend(self._expand_module_search_path(path, top_level, fake=fake))
+
+            if mod_req_paths:
+                mod_req_paths = nub(mod_req_paths)  # remove duplicates
+                mod_lines.append(self.module_generator.prepend_paths(env_var, mod_req_paths))
 
         if self.dry_run:
             self.dry_run_msg('')

From dc09eeeb7716af644e96992530f8bf7cf256fb19 Mon Sep 17 00:00:00 2001
From: Alex Domingo <alex.domingo.toro@vub.be>
Date: Tue, 1 Oct 2024 00:13:33 +0200
Subject: [PATCH 11/21] consider both possible symplink states between lib and
 lib64 in expanding paths for environment of modules

---
 easybuild/framework/easyblock.py | 28 +++++++++++++++-------------
 test/framework/easyblock.py      |  5 ++++-
 2 files changed, 19 insertions(+), 14 deletions(-)

diff --git a/easybuild/framework/easyblock.py b/easybuild/framework/easyblock.py
index 5a27fae724..245f45e0e1 100644
--- a/easybuild/framework/easyblock.py
+++ b/easybuild/framework/easyblock.py
@@ -1618,17 +1618,18 @@ def make_module_req(self, fake=False):
 
         return "".join(mod_lines)
 
-    def _expand_module_search_path(self, search_path, recursive, fake=False):
+    def _expand_module_search_path(self, search_path, top_level, fake=False):
         """
         Expand given path glob and return list of suitable paths to be used as search paths:
-            - Files must exist and directories be non-empty
+            - Paths are relative to installation prefix root
+            - Paths to files must exist and directories be non-empty
             - Fake modules can set search paths to empty directories
-            - Search paths to 'lib64' symlinked to 'lib' are discarded
+            - Search paths to a 'lib64' symlinked to 'lib' are discarded to avoid duplicates
         """
         # Expand globs but only if the string is non-empty
         # empty string is a valid value here (i.e. to prepend the installation prefix root directory)
-        abs_search_path = os.path.join(self.installdir, search_path)
-        exp_search_paths = [abs_search_path] if search_path == "" else glob.glob(abs_search_path)
+        abs_glob = os.path.join(self.installdir, search_path)
+        exp_search_paths = [abs_glob] if search_path == "" else glob.glob(abs_glob)
 
         retained_search_paths = []
         for abs_path in exp_search_paths:
@@ -1636,16 +1637,17 @@ def _expand_module_search_path(self, search_path, recursive, fake=False):
             tentative_path = os.path.relpath(abs_path, start=self.installdir)
             tentative_path = "" if tentative_path == "." else tentative_path  # use empty string instead of dot
 
-            # avoid duplicate entries if lib64 is just a symlink to lib
-            if (tentative_path + os.path.sep).startswith("lib64" + os.path.sep):
-                abs_lib_path = os.path.join(self.installdir, "lib")
-                abs_lib64_path = os.path.join(self.installdir, "lib64")
-                if os.path.islink(abs_lib64_path) and os.path.samefile(abs_lib_path, abs_lib64_path):
-                    self.log.debug("Discarded search path to symlink lib64: %s", tentative_path)
-                    break
+            # avoid duplicate entries between symlinked library dirs
+            tentative_sep = tentative_path + os.path.sep
+            if self.install_lib_symlink == LibSymlink.LIB64 and tentative_sep.startswith("lib64" + os.path.sep):
+                self.log.debug("Discarded search path to symlinked lib64 directory: %s", tentative_path)
+                break
+            if self.install_lib_symlink == LibSymlink.LIB and tentative_sep.startswith("lib" + os.path.sep):
+                self.log.debug("Discarded search path to symlinked lib directory: %s", tentative_path)
+                break
 
             # only retain paths to directories that contain at least one file
-            if os.path.isdir(abs_path) and not dir_contains_files(abs_path, recursive=recursive) and not fake:
+            if os.path.isdir(abs_path) and not dir_contains_files(abs_path, recursive=not top_level) and not fake:
                 self.log.debug("Discarded search path to empty directory: %s", tentative_path)
                 break
 
diff --git a/test/framework/easyblock.py b/test/framework/easyblock.py
index bdf15504f4..5c8091be01 100644
--- a/test/framework/easyblock.py
+++ b/test/framework/easyblock.py
@@ -40,7 +40,7 @@
 
 import easybuild.tools.systemtools as st
 from easybuild.base import fancylogger
-from easybuild.framework.easyblock import EasyBlock, get_easyblock_instance
+from easybuild.framework.easyblock import LibSymlink, EasyBlock, get_easyblock_instance
 from easybuild.framework.easyconfig import CUSTOM
 from easybuild.framework.easyconfig.easyconfig import EasyConfig
 from easybuild.framework.easyconfig.tools import avail_easyblocks, process_easyconfig
@@ -437,6 +437,8 @@ def test_make_module_req(self):
             if isinstance(path, str):
                 path = (path, )
             os.mkdir(os.path.join(eb.installdir, *path))
+        eb.install_lib_symlink = LibSymlink.NEITHER
+
         write_file(os.path.join(eb.installdir, 'foo.jar'), 'foo.jar')
         write_file(os.path.join(eb.installdir, 'bla.jar'), 'bla.jar')
         write_file(os.path.join(eb.installdir, 'share', 'man', 'pi'), 'Man page')
@@ -501,6 +503,7 @@ def test_make_module_req(self):
         write_file(os.path.join(eb.installdir, 'lib', 'libfoo.so'), 'test')
         shutil.rmtree(os.path.join(eb.installdir, 'lib64'))
         os.symlink('lib', os.path.join(eb.installdir, 'lib64'))
+        eb.install_lib_symlink = LibSymlink.LIB64
         with eb.module_generator.start_module_creation():
             guess = eb.make_module_req()
         if get_module_syntax() == 'Tcl':

From 562c98d08918bff0722c938b0127224a2f1e924a Mon Sep 17 00:00:00 2001
From: Alex Domingo <alex.domingo.toro@vub.be>
Date: Tue, 1 Oct 2024 00:17:23 +0200
Subject: [PATCH 12/21] fix code style around ModuleEnvironmentVariable

---
 easybuild/tools/modules.py | 1 +
 1 file changed, 1 insertion(+)

diff --git a/easybuild/tools/modules.py b/easybuild/tools/modules.py
index 5bef0e82bb..4efc78f696 100644
--- a/easybuild/tools/modules.py
+++ b/easybuild/tools/modules.py
@@ -132,6 +132,7 @@
 
 _log = fancylogger.getLogger('modules', fname=False)
 
+
 class ModuleEnvironmentVariable:
     """Environment variable data structure for modules"""
     def __init__(self, paths, empty=False, top_level_file=False):

From 17cc73f81772fe7b589615f72c25654260acfce8 Mon Sep 17 00:00:00 2001
From: Alex Domingo <alex.domingo.toro@vub.be>
Date: Tue, 1 Oct 2024 01:04:10 +0200
Subject: [PATCH 13/21] add check_install_lib_symlink method to EasyBlock to be
 able to trigger explicit checks in the module step

---
 easybuild/framework/easyblock.py | 24 +++++++++++++++++-------
 1 file changed, 17 insertions(+), 7 deletions(-)

diff --git a/easybuild/framework/easyblock.py b/easybuild/framework/easyblock.py
index 245f45e0e1..fcae1fc3bd 100644
--- a/easybuild/framework/easyblock.py
+++ b/easybuild/framework/easyblock.py
@@ -1631,6 +1631,10 @@ def _expand_module_search_path(self, search_path, top_level, fake=False):
         abs_glob = os.path.join(self.installdir, search_path)
         exp_search_paths = [abs_glob] if search_path == "" else glob.glob(abs_glob)
 
+        # Explicitly check symlink state between lib dirs if it is still undefined (e.g. --module-only)
+        if self.install_lib_symlink == LibSymlink.NONE:
+            self.check_install_lib_symlink()
+
         retained_search_paths = []
         for abs_path in exp_search_paths:
             # return relative paths
@@ -1655,6 +1659,17 @@ def _expand_module_search_path(self, search_path, top_level, fake=False):
 
         return retained_search_paths
 
+    def check_install_lib_symlink(self):
+        """Check symlink state between library directories in installation prefix"""
+        lib_dir = os.path.join(self.installdir, 'lib')
+        lib64_dir = os.path.join(self.installdir, 'lib64')
+        if os.path.exists(lib_dir) and os.path.exists(lib64_dir):
+            self.install_lib_symlink = LibSymlink.NEITHER
+            if os.path.islink(lib_dir) and os.path.samefile(lib_dir, lib64_dir):
+                self.install_lib_symlink = LibSymlink.LIB
+            elif os.path.islink(lib64_dir) and os.path.samefile(lib_dir, lib64_dir):
+                self.install_lib_symlink = LibSymlink.LIB64
+
     def make_module_req_guess(self):
         """
         A dictionary of common search path variables to be loaded by environment modules
@@ -3074,13 +3089,8 @@ def post_install_step(self):
             # create *relative* 'lib' symlink to 'lib64';
             symlink('lib64', lib_dir, use_abspath_source=False)
 
-        # check symlink state
-        if os.path.exists(lib_dir) and os.path.exists(lib64_dir):
-            self.install_lib_symlink = LibSymlink.NEITHER
-            if os.path.islink(lib_dir) and os.path.samefile(lib_dir, lib64_dir):
-                self.install_lib_symlink = LibSymlink.LIB
-            elif os.path.islink(lib64_dir) and os.path.samefile(lib_dir, lib64_dir):
-                self.install_lib_symlink = LibSymlink.LIB64
+        # refresh symlink state
+        self.check_install_lib_symlink()
 
         self.run_post_install_commands()
         self.apply_post_install_patches()

From 16e47436d11af407d503a50a3b122e829bbb0211 Mon Sep 17 00:00:00 2001
From: Alex Domingo <alex.domingo.toro@vub.be>
Date: Tue, 1 Oct 2024 01:59:49 +0200
Subject: [PATCH 14/21] remove unused empty attribute from
 ModuleEnvironmentVariable

---
 easybuild/tools/modules.py | 3 +--
 test/framework/modules.py  | 1 -
 2 files changed, 1 insertion(+), 3 deletions(-)

diff --git a/easybuild/tools/modules.py b/easybuild/tools/modules.py
index 4efc78f696..582137f85c 100644
--- a/easybuild/tools/modules.py
+++ b/easybuild/tools/modules.py
@@ -135,9 +135,8 @@
 
 class ModuleEnvironmentVariable:
     """Environment variable data structure for modules"""
-    def __init__(self, paths, empty=False, top_level_file=False):
+    def __init__(self, paths, top_level_file=False):
         self.paths = paths
-        self.empty = bool(empty)
         self.top_level_file = bool(top_level_file)
 
     def __str__(self):
diff --git a/test/framework/modules.py b/test/framework/modules.py
index 4437360359..8e7b1962e9 100644
--- a/test/framework/modules.py
+++ b/test/framework/modules.py
@@ -1593,7 +1593,6 @@ def test_module_environment_variable(self):
         test_paths = ['lib', 'lib64']
         mod_envar = mod.ModuleEnvironmentVariable(test_paths)
         self.assertTrue(hasattr(mod_envar, "paths"))
-        self.assertTrue(hasattr(mod_envar, "empty"))
         self.assertTrue(hasattr(mod_envar, "top_level_file"))
         self.assertEqual(mod_envar.paths, test_paths)
         self.assertEqual(str(mod_envar), "lib:lib64")

From f68f383cdea1726f55f98585e1b2da987e36f992 Mon Sep 17 00:00:00 2001
From: Alex Domingo <alex.domingo.toro@vub.be>
Date: Tue, 1 Oct 2024 02:00:44 +0200
Subject: [PATCH 15/21] attributes in ModuleLoadEnvironment can only be
 instances of ModuleEnvironmentVariable

---
 easybuild/tools/modules.py | 70 +++++++++++++++++---------------------
 test/framework/modules.py  | 23 ++++++++-----
 2 files changed, 47 insertions(+), 46 deletions(-)

diff --git a/easybuild/tools/modules.py b/easybuild/tools/modules.py
index 582137f85c..a0bc842d41 100644
--- a/easybuild/tools/modules.py
+++ b/easybuild/tools/modules.py
@@ -182,49 +182,45 @@ def __init__(self):
         Paths are relative to root of installation directory
         """
 
-        self.PATH = ModuleEnvironmentVariable(
+        self.PATH = (
             SEARCH_PATH_BIN_DIRS + ['sbin'],
-            top_level_file=True,
+            {"top_level_file": True},
         )
-        self.LD_LIBRARY_PATH = ModuleEnvironmentVariable(
+        self.LD_LIBRARY_PATH = (
             SEARCH_PATH_LIB_DIRS,
-            top_level_file=True,
-        )
-        self.LIBRARY_PATH = ModuleEnvironmentVariable(
-            SEARCH_PATH_LIB_DIRS,
-        )
-        self.CPATH = ModuleEnvironmentVariable(
-            SEARCH_PATH_HEADER_DIRS,
-        )
-        self.MANPATH = ModuleEnvironmentVariable(
-            ['man', os.path.join('share', 'man')],
-        )
-        self.PKG_CONFIG_PATH = ModuleEnvironmentVariable(
-            [os.path.join(x, 'pkgconfig') for x in SEARCH_PATH_LIB_DIRS + ['share']],
-        )
-        self.ACLOCAL_PATH = ModuleEnvironmentVariable(
-            [os.path.join('share', 'aclocal')],
-        )
-        self.CLASSPATH = ModuleEnvironmentVariable(
-            ['*.jar'],
-        )
-        self.XDG_DATA_DIRS = ModuleEnvironmentVariable(
-            ['share'],
-        )
-        self.GI_TYPELIB_PATH = ModuleEnvironmentVariable(
-            [os.path.join(x, 'girepository-*') for x in SEARCH_PATH_LIB_DIRS]
-        )
-        self.CMAKE_PREFIX_PATH = ModuleEnvironmentVariable(
-            [''],
+            {"top_level_file": True},
         )
+        self.LIBRARY_PATH = SEARCH_PATH_LIB_DIRS
+        self.CPATH = SEARCH_PATH_HEADER_DIRS
+        self.MANPATH = ['man', os.path.join('share', 'man')]
+        self.PKG_CONFIG_PATH = [os.path.join(x, 'pkgconfig') for x in SEARCH_PATH_LIB_DIRS + ['share']]
+        self.ACLOCAL_PATH = [os.path.join('share', 'aclocal')]
+        self.CLASSPATH = ['*.jar']
+        self.XDG_DATA_DIRS = ['share']
+        self.GI_TYPELIB_PATH = [os.path.join(x, 'girepository-*') for x in SEARCH_PATH_LIB_DIRS]
+        self.CMAKE_PREFIX_PATH = ['']
         # only needed for installations whith standalone lib64
-        self.CMAKE_LIBRARY_PATH = ModuleEnvironmentVariable(
-            ['lib64'],
-        )
+        self.CMAKE_LIBRARY_PATH = ['lib64']
+
+    def __setattr__(self, name, value):
+        """
+        Specific restrictions for ModuleLoadEnvironment attributes:
+        - attribute names are uppercase
+        - attributes are instances of ModuleEnvironmentVariable
+        """
+        try:
+            (paths, kwargs) = value
+        except ValueError:
+            paths, kwargs = value, {}
+        else:
+            if not isinstance(kwargs, dict):
+                paths, kwargs = value, {}
+
+        return super().__setattr__(name.upper(), ModuleEnvironmentVariable(paths, **kwargs))
 
     def __iter__(self):
         """Make the class iterable"""
-        yield from (envar for envar in self.__dict__ if isinstance(getattr(self, envar), ModuleEnvironmentVariable))
+        yield from self.__dict__
 
     def items(self):
         """
@@ -233,9 +229,7 @@ def items(self):
         - value = its "paths" attribute
         """
         for attr in self.__dict__:
-            envar = getattr(self, attr)
-            if isinstance(envar, ModuleEnvironmentVariable):
-                yield attr, envar.paths
+            yield attr, getattr(self, attr).paths
 
     @property
     def environ(self):
diff --git a/test/framework/modules.py b/test/framework/modules.py
index 8e7b1962e9..bfbb6666a2 100644
--- a/test/framework/modules.py
+++ b/test/framework/modules.py
@@ -1616,24 +1616,31 @@ def test_module_environment_variable(self):
 
     def test_module_load_environment(self):
         """Test for ModuleLoadEnvironment object"""
+        test_paths = ['lib', 'lib64']
         mod_load_env = mod.ModuleLoadEnvironment()
-        mod_load_env.TEST_VAR = mod.ModuleEnvironmentVariable(["lib", "lib64"])
+        mod_load_env.TEST_VAR = test_paths
         self.assertTrue(hasattr(mod_load_env, "TEST_VAR"))
-        self.assertEqual(mod_load_env.TEST_VAR.paths, ["lib", "lib64"])
+        self.assertEqual(mod_load_env.TEST_VAR.paths, test_paths)
 
-        # copy current state as reference
         ref_load_env = mod_load_env.__dict__.copy()
-        # and add some garbage
-        mod_load_env.garbage = "not_an_env_var"
-        self.assertTrue(hasattr(mod_load_env, "garbage"))
-        self.assertEqual(mod_load_env.garbage, "not_an_env_var")
-
         self.assertCountEqual(list(mod_load_env), ref_load_env.keys())
         ref_load_env_item_list = [(key, value.paths) for key, value in ref_load_env.items()]
         self.assertCountEqual(list(mod_load_env.items()), ref_load_env_item_list)
         ref_load_env_environ = {key: value.paths for key, value in ref_load_env.items()}
         self.assertDictEqual(mod_load_env.environ, ref_load_env_environ)
 
+        mod_load_env.test_lower = test_paths
+        self.assertTrue(hasattr(mod_load_env, "TEST_LOWER"))
+        self.assertEqual(mod_load_env.TEST_LOWER.paths, test_paths)
+        mod_load_env.TEST_STR = "some/path"
+        self.assertTrue(hasattr(mod_load_env, "TEST_STR"))
+        self.assertEqual(mod_load_env.TEST_STR.paths, ["some/path"])
+        mod_load_env.TEST_EXTRA = (test_paths, {"top_level_file": True})
+        self.assertTrue(hasattr(mod_load_env, "TEST_EXTRA"))
+        self.assertEqual(mod_load_env.TEST_EXTRA.paths, test_paths)
+        self.assertEqual(mod_load_env.TEST_EXTRA.top_level_file, True)
+        self.assertRaises(TypeError, setattr, mod_load_env, "TEST_UNKNONW", (test_paths, {"unkown_param": True}))
+
 
 def suite():
     """ returns all the testcases in this module """

From 36d4f9274ffd429dfd935be3d1b35a3767ec4ff2 Mon Sep 17 00:00:00 2001
From: Kenneth Hoste <kenneth.hoste@ugent.be>
Date: Mon, 7 Oct 2024 10:18:54 +0200
Subject: [PATCH 16/21] add test to verify that environment variables don't
 leak into module file of subsequent installations

---
 .../sandbox/easybuild/easyblocks/t/toy.py     |  7 ++++
 test/framework/toy_build.py                   | 36 +++++++++++++++++++
 2 files changed, 43 insertions(+)

diff --git a/test/framework/sandbox/easybuild/easyblocks/t/toy.py b/test/framework/sandbox/easybuild/easyblocks/t/toy.py
index 5727dcd0e0..552b5d8a37 100644
--- a/test/framework/sandbox/easybuild/easyblocks/t/toy.py
+++ b/test/framework/sandbox/easybuild/easyblocks/t/toy.py
@@ -192,3 +192,10 @@ def make_module_extra(self):
         txt = super(EB_toy, self).make_module_extra()
         txt += self.module_generator.set_environment('TOY', os.getenv('TOY', '<TOY_env_var_not_defined>'))
         return txt
+
+    def make_module_req_guess(self):
+        """Extra paths for environment variables to consider"""
+        guesses = super(EB_toy, self).make_module_req_guess()
+        if self.name == 'toy':
+            guesses['CPATH'].append('toy-headers')
+        return guesses
diff --git a/test/framework/toy_build.py b/test/framework/toy_build.py
index edd9e94fcc..6edef42c5d 100644
--- a/test/framework/toy_build.py
+++ b/test/framework/toy_build.py
@@ -4302,6 +4302,42 @@ def test_toy_python(self):
         self.assertTrue(ebpythonprefixes_regex.search(toy_mod_txt),
                         f"Pattern '{ebpythonprefixes_regex.pattern}' found in: {toy_mod_txt}")
 
+    def test_toy_multiple_ecs_module(self):
+        """
+        Verify whether module file is correct when multiple easyconfigs are being installed.
+        """
+        test_ecs = os.path.join(os.path.dirname(os.path.abspath(__file__)), 'easyconfigs', 'test_ecs')
+        toy_ec = os.path.join(test_ecs, 't', 'toy', 'toy-0.0.eb')
+
+        # modify 'toy' easyconfig so toy-headers subdirectory is created,
+        # which is taken into account by EB_toy easyblock for $CPATH
+        test_toy_ec = os.path.join(self.test_prefix, 'test-toy.eb')
+        toy_ec_txt = read_file(toy_ec)
+        toy_ec_txt += "\npostinstallcmds += ['mkdir %(installdir)s/toy-headers']"
+        toy_ec_txt += "\npostinstallcmds += ['touch %(installdir)s/toy-headers/toy.h']"
+        write_file(test_toy_ec, toy_ec_txt)
+
+        # modify 'toy-app' easyconfig so toy-headers subdirectory is created,
+        # which is consider by EB_toy easyblock for $CPATH,
+        # but should *not* be actually used because software name is not 'toy'
+        toy_app_ec = os.path.join(test_ecs, 't', 'toy-app', 'toy-app-0.0.eb')
+        test_toy_app_ec = os.path.join(self.test_prefix, 'test-toy-app.eb')
+        toy_ec_txt = read_file(toy_app_ec)
+        toy_ec_txt += "\npostinstallcmds += ['mkdir %(installdir)s/toy-headers']"
+        toy_ec_txt += "\npostinstallcmds += ['touch %(installdir)s/toy-headers/toy.h']"
+        write_file(test_toy_app_ec, toy_ec_txt)
+
+        self.run_test_toy_build_with_output(ec_file=test_toy_ec, extra_args=[test_toy_app_ec])
+
+        toy_modtxt = read_file(os.path.join(self.test_installpath, 'modules', 'all', 'toy', '0.0.lua'))
+        regex = re.compile('prepend[-_]path.*CPATH.*toy-headers', re.M)
+        self.assertTrue(regex.search(toy_modtxt),
+                        f"Pattern '{regex.pattern}' should be found in: {toy_modtxt}")
+
+        toy_app_modtxt = read_file(os.path.join(self.test_installpath, 'modules', 'all', 'toy-app', '0.0.lua'))
+        self.assertFalse(regex.search(toy_app_modtxt),
+                         f"Pattern '{regex.pattern}' should *not* be found in: {toy_app_modtxt}")
+
 
 def suite():
     """ return all the tests in this file """

From d560ce20e22c7750934127d9ad5ed35c6a2e643d Mon Sep 17 00:00:00 2001
From: Alex Domingo <alex.domingo.toro@vub.be>
Date: Wed, 6 Nov 2024 09:36:53 +0100
Subject: [PATCH 17/21] convert ModuleLoadEnvironment to regular class instead
 of singleton

---
 easybuild/tools/modules.py | 9 ++-------
 1 file changed, 2 insertions(+), 7 deletions(-)

diff --git a/easybuild/tools/modules.py b/easybuild/tools/modules.py
index 16212f9fd5..e3868807af 100644
--- a/easybuild/tools/modules.py
+++ b/easybuild/tools/modules.py
@@ -43,12 +43,11 @@
 import shlex
 
 from easybuild.base import fancylogger
-from easybuild.base.wrapper import create_base_metaclass
 from easybuild.tools import LooseVersion
 from easybuild.tools.build_log import EasyBuildError, EasyBuildExit, print_warning
 from easybuild.tools.config import ERROR, IGNORE, PURGE, UNLOAD, UNSET
 from easybuild.tools.config import EBROOT_ENV_VAR_ACTIONS, LOADED_MODULES_ACTIONS
-from easybuild.tools.config import Singleton, build_option, get_modules_tool, install_path
+from easybuild.tools.config import build_option, get_modules_tool, install_path
 from easybuild.tools.config import SEARCH_PATH_BIN_DIRS, SEARCH_PATH_HEADER_DIRS, SEARCH_PATH_LIB_DIRS
 from easybuild.tools.environment import ORIG_OS_ENVIRON, restore_env, setvar, unset_env_vars
 from easybuild.tools.filetools import convert_name, mkdir, normalize_path, path_matches, read_file, which, write_file
@@ -169,11 +168,7 @@ def prepend(self, item):
         self.paths.insert(0, item)
 
 
-# singleton metaclass: only one instance is created
-BaseModuleEnvironment = create_base_metaclass('BaseModuleEnvironment', Singleton, object)
-
-
-class ModuleLoadEnvironment(BaseModuleEnvironment):
+class ModuleLoadEnvironment:
     """Environment set by modules on load"""
 
     def __init__(self):

From 9a230cf27967228091dbac34a60c8ced732200ff Mon Sep 17 00:00:00 2001
From: Kenneth Hoste <kenneth.hoste@ugent.be>
Date: Wed, 6 Nov 2024 13:52:06 +0100
Subject: [PATCH 18/21] enable raising of errors when running toy build in
 test_toy_multiple_ecs_module

---
 test/framework/toy_build.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/test/framework/toy_build.py b/test/framework/toy_build.py
index 6385880fef..c5df316bab 100644
--- a/test/framework/toy_build.py
+++ b/test/framework/toy_build.py
@@ -4345,7 +4345,7 @@ def test_toy_multiple_ecs_module(self):
         toy_ec_txt += "\npostinstallcmds += ['touch %(installdir)s/toy-headers/toy.h']"
         write_file(test_toy_app_ec, toy_ec_txt)
 
-        self.run_test_toy_build_with_output(ec_file=test_toy_ec, extra_args=[test_toy_app_ec])
+        self.run_test_toy_build_with_output(ec_file=test_toy_ec, extra_args=[test_toy_app_ec], raise_error=True)
 
         toy_modtxt = read_file(os.path.join(self.test_installpath, 'modules', 'all', 'toy', '0.0.lua'))
         regex = re.compile('prepend[-_]path.*CPATH.*toy-headers', re.M)

From f43ae679517e3b8f342c056406c4f2f493617321 Mon Sep 17 00:00:00 2001
From: Kenneth Hoste <kenneth.hoste@ugent.be>
Date: Thu, 7 Nov 2024 08:14:20 +0100
Subject: [PATCH 19/21] fix test_toy_multiple_ecs_module when using Tcl as
 module syntax

---
 test/framework/toy_build.py | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/test/framework/toy_build.py b/test/framework/toy_build.py
index c5df316bab..821999b30d 100644
--- a/test/framework/toy_build.py
+++ b/test/framework/toy_build.py
@@ -4347,12 +4347,18 @@ def test_toy_multiple_ecs_module(self):
 
         self.run_test_toy_build_with_output(ec_file=test_toy_ec, extra_args=[test_toy_app_ec], raise_error=True)
 
-        toy_modtxt = read_file(os.path.join(self.test_installpath, 'modules', 'all', 'toy', '0.0.lua'))
+        toy_mod = os.path.join(self.test_installpath, 'modules', 'all', 'toy', '0.0')
+        if get_module_syntax() == 'Lua':
+            toy_mod += '.lua'
+        toy_modtxt = read_file(toy_mod)
         regex = re.compile('prepend[-_]path.*CPATH.*toy-headers', re.M)
         self.assertTrue(regex.search(toy_modtxt),
                         f"Pattern '{regex.pattern}' should be found in: {toy_modtxt}")
 
-        toy_app_modtxt = read_file(os.path.join(self.test_installpath, 'modules', 'all', 'toy-app', '0.0.lua'))
+        toy_app_mod = os.path.join(self.test_installpath, 'modules', 'all', 'toy-app', '0.0')
+        if get_module_syntax() == 'Lua':
+            toy_app_mod += '.lua'
+        toy_app_modtxt = read_file(toy_app_mod)
         self.assertFalse(regex.search(toy_app_modtxt),
                          f"Pattern '{regex.pattern}' should *not* be found in: {toy_app_modtxt}")
 

From fad0926164bdb03284be440e3df69c1928711576 Mon Sep 17 00:00:00 2001
From: Alex Domingo <alex.domingo.toro@vub.be>
Date: Wed, 13 Nov 2024 11:44:11 +0100
Subject: [PATCH 20/21] fix deprecation warning about make_module_req_guess

---
 easybuild/framework/easyblock.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/easybuild/framework/easyblock.py b/easybuild/framework/easyblock.py
index 9a8652c740..0b78bb81b8 100644
--- a/easybuild/framework/easyblock.py
+++ b/easybuild/framework/easyblock.py
@@ -1638,8 +1638,8 @@ def make_module_req(self, fake=False):
             env_var_requirements = self.module_load_environment.environ
         else:
             # Custom deprecated method used by child EasyBlock
-            self.log.devel(
-                "make_module_req_guess() is deprecated, use module_load_environment object instead.",
+            self.log.deprecated(
+                "make_module_req_guess() is deprecated, use EasyBlock.module_load_environment instead.",
                 "6.0",
             )
             env_var_requirements = self.make_module_req_guess()

From 5f04fc34b7c049f165bacd55b9cd71d36c4941ea Mon Sep 17 00:00:00 2001
From: Alex Domingo <alex.domingo.toro@vub.be>
Date: Wed, 13 Nov 2024 13:39:47 +0100
Subject: [PATCH 21/21] make ModuleEnvironmentVariable iterable

---
 easybuild/tools/modules.py | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/easybuild/tools/modules.py b/easybuild/tools/modules.py
index e3868807af..65273db7d1 100644
--- a/easybuild/tools/modules.py
+++ b/easybuild/tools/modules.py
@@ -141,6 +141,9 @@ def __init__(self, paths, top_level_file=False):
     def __str__(self):
         return ":".join(self.paths)
 
+    def __iter__(self):
+        return iter(self.paths)
+
     @property
     def paths(self):
         return self._paths
@@ -207,9 +210,9 @@ def __setattr__(self, name, value):
             (paths, kwargs) = value
         except ValueError:
             paths, kwargs = value, {}
-        else:
-            if not isinstance(kwargs, dict):
-                paths, kwargs = value, {}
+
+        if not isinstance(kwargs, dict):
+            paths, kwargs = value, {}
 
         return super().__setattr__(name.upper(), ModuleEnvironmentVariable(paths, **kwargs))