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

[Wesley Schwengle <wesleys@opperschaap.net>]

Via 842587016d717394a001a6f8959475bf8df56124 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.

Signed-off-by: Wesley Schwengle <wesleys@opperschaap.net>
---
 Completion/Unix/Command/_git | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/Completion/Unix/Command/_git b/Completion/Unix/Command/_git
index 1d4fe20c9..dd2c1ec74 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 +7413,19 @@ __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 ("$gtrailers[@]")
+  do
+    trailers+=(${${(@s:.:)i}[2]})
+  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