fix: syntax mismatch in git diff

Author: rockyzhang24

syntax/gitmessengerpopup.vim

@@ -2,10 +2,18 @@ if exists('b:current_syntax')
     finish
 endif
 
-syn match gitmessengerHeader '^ \=\%(History\|Commit\|\%(Author \|Committer \)\=Date\|Author\|Committer\):' display
-syn match gitmessengerHash '\%(^ \=Commit: \+\)\@<=[[:xdigit:]]\+' display
-syn match gitmessengerHistory '\%(^ \=History: \+\)\@<=#\d\+' display
-syn match gitmessengerEmail '\%(^ \=\%(Author\|Committer\): \+.*\)\@<=<.\+>' display
+if get(g:, 'git_messenger_popup_content_margins', v:true)
+    let margin_pat = '^ '
+else
+    let margin_pat = '^'
+endif
+
+syn sync fromstart
+
+exe 'syn match gitmessengerHeader "' . margin_pat . '\%(History\|Commit\|\%(Author \|Committer \)\=Date\|Author\|Committer\):" display'
+exe 'syn match gitmessengerHash "\%(' . margin_pat . 'Commit: \+\)\@<=[[:xdigit:]]\+" display'
+exe 'syn match gitmessengerHistory "\%(' . margin_pat . 'History: \+\)\@<=#\d\+" display'
+exe 'syn match gitmessengerEmail "\%(' . margin_pat . '\%(Author\|Committer\): \+.*\)\@<=<.\+>" display'
 
 " Diff included in popup
 " There are two types of diff format; 'none' 'current', 'all', 'current.word', 'all.word'.
@@ -14,22 +22,24 @@ syn match gitmessengerEmail '\%(^ \=\%(Author\|Committer\): \+.*\)\@<=<.\+>' dis
 " b:__gitmessenger_diff is set by Blame.render() in blame.vim.
 if get(b:, '__gitmessenger_diff', '') =~# '\.word$'
     if has('conceal') && get(g:, 'git_messenger_conceal_word_diff_marker', v:true)
-        syn region diffWordsRemoved matchgroup=Conceal start=/\[-/ end=/-]/ concealends oneline
-        syn region diffWordsAdded matchgroup=Conceal start=/{+/ end=/+}/ concealends oneline
+        syn region diffWordsRemoved matchgroup=Conceal start=/\[-/ end=/-]/ concealends oneline contained containedin=gitDiff
+        syn region diffWordsAdded matchgroup=Conceal start=/{+/ end=/+}/ concealends oneline contained containedin=gitDiff
     else
-        syn region diffWordsRemoved start=/\[-/ end=/-]/ oneline
-        syn region diffWordsAdded start=/{+/ end=/+}/ oneline
+        syn region diffWordsRemoved start=/\[-/ end=/-]/ oneline contained containedin=gitDiff
+        syn region diffWordsAdded start=/{+/ end=/+}/ oneline contained containedin=gitDiff
     endif
 else
-    syn match diffRemoved "^ \=-.*" display
-    syn match diffAdded "^ \=+.*" display
+    exe 'syn match diffRemoved "' . margin_pat . '-.*" contained containedin=gitDiff display'
+    exe 'syn match diffAdded "' . margin_pat . '+.*" contained containedin=gitDiff display'
 endif
 
-syn match diffFile "^ \=diff --git .*" display
-syn match diffOldFile "^ \=--- a\>.*" display
-syn match diffNewFile "^ \=+++ b\>.*" display
-syn match diffIndexLine "^ \=index \x\{7,}\.\.\x\{7,}.*" display
-syn match diffLine "^ \=@@ .*" display
+exe 'syn match diffFile "' . margin_pat . 'diff --git .*" display'
+exe 'syn match diffOldFile "' . margin_pat . '--- \(a\>.*\|/dev/null\)" display'
+exe 'syn match diffNewFile "' . margin_pat . '+++ \(b\>.*\|/dev/null\)" display'
+exe 'syn match diffIndexLine "' . margin_pat . 'index \x\{7,}\.\.\x\{7,}.*" display'
+exe 'syn match diffLine "' . margin_pat . '@@ .*" contained containedin=gitDiff display'
+
+exec 'syn region gitDiff start=/' . margin_pat . '\%(@@ -\)\@=/ end=/' . margin_pat . '\%(diff --git\)\@=/ contains=diffRemoved,diffAdded,diffLine,diffWordsRemoved,diffWordsAdded'
 
 hi def link gitmessengerHeader      Identifier
 hi def link gitmessengerHash        Comment