[PATCH v2]] completion: _git: Add trailer token completion for git commit --trailer

[Wesley Schwengle <wesleys@xxxxxxxxxxxxxxx>]

Via 842587016d in the git project there has been support for git commit
trailer tokens for the bash completion system. This commit adds similar
support to zsh. It includes additional hardening of the regexp and
allows for tokens which include a '.'. This can be found in git via
9a0ec17606.

Signed-off-by: Wesley Schwengle <wesleys@xxxxxxxxxxxxxxx>
---
 Completion/Unix/Command/_git | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/Completion/Unix/Command/_git b/Completion/Unix/Command/_git
index 1d4fe20c9..3b9041303 100644
--- a/Completion/Unix/Command/_git
+++ b/Completion/Unix/Command/_git
@@ -717,7 +717,7 @@ _git-commit () {
     {-p,--patch}'[use the interactive patch selection interface to chose which changes to commit]' \
     '(--reset-author)--author[override the author name used in the commit]:author name' \
     '--date=[override the author date used in the commit]:date' \
-    '*--trailer=[add custom trailer(s)]:trailer' \
+    '*--trailer=[add custom trailer(s)]:trailer :__git_trailers_tokens' \
     '(-s --signoff)'{-s,--signoff}'[add Signed-off-by trailer at the end of the commit message]' \
     '(-n --no-verify)'{-n,--no-verify}'[bypass pre-commit and commit-msg hooks]' \
     '--allow-empty[allow recording an empty commit]' \
@@ -7413,6 +7413,20 @@ __git_deleted_files () {
   __git_files --deleted deleted-files 'deleted file' $*
 }
 
+
+(( $+functions[__git_trailers_tokens] )) ||
+__git_trailers_tokens () {
+  declare -a trailers
+
+  local -a gtrailers=($(git config --name-only --get-regexp '^trailer\..*\.key$'))
+  for i ("$gtrailers[@]")
+  do
+    i=(${${(@s:.:)i}[2,-2]});
+    trailers+=(${(j|.|)i})
+  done
+  _wanted trailer expl "trailer" compadd -a trailers
+}
+
 (( $+functions[__git_modified_files] )) ||
 __git_modified_files () {
   __git_files --modified modified-files 'modified file' $*
-- 
2.42.0.465.g461bb28fbd