[PATCH 2/2 v2] git-gui - provide commit base to the hooks/pre-commit script

If hooks/pre-commit acts based upon the changes to be checked in
rather than just the resulting content, the script needs to know which
commit to use. For a normal commit, this is HEAD, but when amending this
is HEAD~1. So, this modifies commit.tcl to pass $1 as HEAD|HEAD~1 depending
upon the commit type. Existing scripts are unaffected as they did not
expect any argument so will silently ignore this extra bit of info.

Signed-off-by: Mark Levedahl <redacted>
---
 git-gui/lib/commit.tcl |    8 +++++++-
 1 files changed, 7 insertions(+), 1 deletions(-)

diff --git a/git-gui/lib/commit.tcl b/git-gui/lib/commit.tcl
index 7f459cd..a62edc9 100644
--- a/git-gui/lib/commit.tcl
+++ b/git-gui/lib/commit.tcl

@@ -225,7 +225,13 @@ A good commit message has the following format:
 
 	# -- Run the pre-commit hook.
 	#
-	set fd_ph [githook_read pre-commit]
+	if {[string compare $commit_type "normal"] == 0} {
+		set against "HEAD"
+	} else {
+		set against "HEAD~1"
+	}
+
+	set fd_ph [githook_read pre-commit $against]
 	if {$fd_ph eq {}} {
 		commit_commitmsg $curHEAD $msg_p
 		return

-- 
1.7.1.269.g9fb6