tools: fix luacheck invocation in different cases

Now `make luacheck` gracefully handles different cases: in-source and
out-of-source build (within the source tree or outside), current working
directory as a real path or with symlink components.

As result of looking into those problems I filed the issue [1] against
luacheck. It seems, there are problems around absolute paths with
symlinks components.

[1]: mpeterv/luacheck#208

CMakeLists.txt

@@ -25,7 +25,6 @@ find_program(BASH bash)
 find_program(GIT git)
 find_program(LD ld)
 find_program(CTAGS ctags)
-find_program(LUACHECK luacheck ENV PATH)
 
 # Define PACKAGE macro in tarantool/config.h
 set(PACKAGE "Tarantool" CACHE STRING "Package name.")
@@ -157,10 +156,10 @@ add_custom_target(ctags DEPENDS tags)
 #
 # Enable 'make luacheck' target.
 #
-
 add_custom_target(luacheck)
 add_custom_command(TARGET luacheck
-    COMMAND ${LUACHECK} --codes --config "${PROJECT_SOURCE_DIR}/.luacheckrc" "${PROJECT_SOURCE_DIR}"
+    COMMAND "${PROJECT_SOURCE_DIR}/tools/run-luacheck.sh"
+            "${PROJECT_SOURCE_DIR}" "${PROJECT_BINARY_DIR}"
     COMMENT "Perform static analysis of Lua code"
 )
 

tools/run-luacheck.sh

@@ -0,0 +1,71 @@
+#!/bin/sh
+
+set -eux
+
+SOURCE_DIR="${1:-}"
+BUILD_DIR="${2:-}"
+
+if [ -z "${SOURCE_DIR}" ] || [ -z "${BUILD_DIR}" ]; then
+    printf "Usage: ${0} /path/to/the/source/tree /path/to/the/build/directory\n"
+    exit 1
+fi
+
+if ! type luacheck; then
+    printf "Unable to find luacheck\n"
+    exit 1
+fi
+
+# Workaround luacheck behaviour around the `include_files`
+# configuration option, a current working directory and a
+# directory path passed as an argument.
+#
+# https://github.com/mpeterv/luacheck/issues/208
+#
+# If we'll just invoke the following command under the
+# `make luacheck` target:
+#
+#  | luacheck --codes                                 \
+#  |     --config "${PROJECT_SOURCE_DIR}/.luacheckrc" \
+#  |     "${PROJECT_SOURCE_DIR}"
+#
+# The linter will fail to find Lua sources in the following cases:
+#
+# 1. In-source build. The current working directory is not a
+#    real path (contains components, which are symlinks).
+# 2. Out-of-source build.
+#
+# It seems, the only reliable way to verify sources is to change
+# the current directory prior to the luacheck call.
+cd "${SOURCE_DIR}"
+
+# Exclude the build directory if it is under the source directory.
+#
+# Except the case, when the build directory is the same as the
+# source directory.
+#
+# We lean on the following assumptions:
+#
+# 1. "${SOURCE_DIR}" and "${BUILD_DIR}" have no the trailing slash.
+# 2. "${SOURCE_DIR}" and "${BUILD_DIR}" are either real paths
+#    (with resolved symlink components) or absolute paths with the
+#    same symlink components (where applicable).
+#
+# Those assumptions should be true when the variables are passed
+# from the CMake variables "${PROJECT_SOURCE_DIR}" and
+# "${PROJECT_BINARY_DIR}".
+#
+# When the prerequisites are hold true, the EXCLUDE_FILES pattern
+# will be relative to the "${SOURCE_DIR}" and luacheck will work
+# as expected.
+EXCLUDE_FILES=""
+case "${BUILD_DIR}" in
+"${SOURCE_DIR}/"*)
+    EXCLUDE_FILES="${BUILD_DIR#"${SOURCE_DIR}/"}/**/*.lua"
+    ;;
+esac
+
+if [ -z "${EXCLUDE_FILES}" ]; then
+    luacheck --codes --config .luacheckrc .
+else
+    luacheck --codes --config .luacheckrc . --exclude-files "${EXCLUDE_FILES}"
+fi