[PATCH] completion: complete refs for "git commit -c"

The "-c" and "-C" options take an existing commit, so let's
complete refs, just as we would for --squash or --fixup.

Signed-off-by: Jeff King <redacted>
---
I notice that the existing code just handles the "--foo=bar" form of most
options. By checking $prev, we can also handle "--foo bar" form (which
we have to do for short options like "-c"). But it would mean
duplicating all of the existing logic. I don't know if it's worth it or
not, given that nobody has complained.

 contrib/completion/git-completion.bash | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/contrib/completion/git-completion.bash b/contrib/completion/git-completion.bash
index 0b77eb1..a4c48e1 100644
--- a/contrib/completion/git-completion.bash
+++ b/contrib/completion/git-completion.bash

@@ -971,6 +971,13 @@ _git_commit ()
 {
 	__git_has_doubledash && return
 
+	case "$prev" in
+	-c|-C)
+		__gitcomp_nl "$(__git_refs)" "" "${cur}"
+		return
+		;;
+	esac
+
 	case "$cur" in
 	--cleanup=*)
 		__gitcomp "default strip verbatim whitespace

-- 
1.8.0.2.4.g59402aa