[Diff] Support multiline email headers

Git Formats/Git Diff.sublime-syntax

@@ -75,6 +75,8 @@ contexts:
   email-header-person-body:
     - meta_scope: meta.mapping.diff
     - include: scope:text.git.mailmap
+    # The mailmap include has bad interactions with
+    # pop-before-next-email-header
     - include: pop-before-eol
 
   email-header-commit:
@@ -88,7 +90,7 @@ contexts:
     - meta_scope: meta.mapping.diff
     - match: '{{git_hash}}'
       scope: constant.other.hash.git
-    - include: pop-before-eol
+    - include: pop-before-next-email-header
 
   email-header-subject-line:
     - match: ^(Subject)(:)
@@ -101,7 +103,7 @@ contexts:
     - meta_scope: meta.mapping.diff
     - meta_content_scope: markup.heading.diff
     - include: patch-annotation
-    - include: pop-before-eol
+    - include: pop-before-next-email-header
 
   patch-annotation:
     - match: (\[)(?:(RFC) )?PATCH
@@ -149,7 +151,7 @@ contexts:
         2: punctuation.separator.date.diff
         3: punctuation.separator.date.diff
         4: storage.modifier.diff
-    - include: pop-before-eol
+    - include: pop-before-next-email-header
 
   email-header-generic:
     - match: ^\b([\w-]+)\b(:)
@@ -160,7 +162,7 @@ contexts:
 
   email-header-generic-body:
     - meta_scope: meta.mapping.diff
-    - include: pop-before-eol
+    - include: pop-before-next-email-header
 
   email-body:
     - meta_content_scope: meta.block.git-body.diff
@@ -542,6 +544,11 @@ contexts:
     - match: ^{{next_diff_header}}
       pop: 1
 
+  pop-before-next-email-header:
+    # Hack in `\` to support unit tests
+    - match: ^(?! \S|\\)
+      pop: 1
+
 ###############################################################################
 
 variables:

Git Formats/tests/syntax_test_git_diff.patch

@@ -23,7 +23,7 @@ Date: Tue, 13 Jul 2010 11:42:54 -0700
 \                        ^ punctuation.separator.date.diff
 \                           ^ punctuation.separator.date.diff
 \                               ^^^^^ storage.modifier.diff
-Subject: [PATCH v2 1/2] [IA64] Put ia64 config files on the Uwe Kleine-Koenig diet
+Subject: [PATCH v2 1/2] [IA64] Put ia64 config files on the Uwe Kleine-Koenig
 \^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ meta.block.git-header.diff meta.mapping.diff
 \               ^^ meta.annotation.patch-version.diff storage.modifier.diff
 \                  ^^^ meta.annotation.patch-sequence.diff
@@ -36,6 +36,8 @@ Subject: [PATCH v2 1/2] [IA64] Put ia64 config files on the Uwe Kleine-Koenig di
 \                   ^ punctuation.separator.sequence.diff
 \                    ^ meta.number.integer.decimal.diff constant.numeric.value.diff
 \                     ^ punctuation.definition.annotation.end.diff
+ diet
+\^^^^^ meta.block.git-header.diff meta.mapping.diff markup.heading.diff
 MIME-Version: 1.0
 Content-Type: text/plain; charset=UTF-8
 \^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ meta.block.git-header.diff meta.mapping.diff