git-gui: Save the merge base during checkout_op processing

I've decided to teach checkout_op how to perform more than just a
fast-forward and reset type of merge.  This way we can also do a full
recursive merge even when we are recreating an existing branch from
a remote.  To help with that process I'm saving the merge-base we
computed during the ff/reset/fail decision process, in case we need
it later on when we actually start a true merge operation.

Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

diff --git a/lib/checkout_op.tcl b/lib/checkout_op.tcl
index 00a994be120edaa1024733cb94e3f1fe4e494039..262dc96895aa76a6930e98719533a61771775723 100644 (file)
--- a/lib/checkout_op.tcl
+++ b/lib/checkout_op.tcl
@@ -12,6 +12,7 @@ field new_ref    ; # ref we are updating/creating
 
 field parent_w      .; # window that started us
 field merge_type none; # type of merge to apply to existing branch
+field merge_base   {}; # merge base if we have another ref involved
 field fetch_spec   {}; # refetch tracking branch if used?
 field checkout      1; # actually checkout the branch?
 field create        0; # create the branch if it doesn't exist?
@@ -180,15 +181,14 @@ method _update_ref {} {
                # No merge would be required, don't compute anything.
                #
        } else {
-               set mrb {}
-               catch {set mrb [git merge-base $new $cur]}
+               catch {set merge_base [git merge-base $new $cur]}
                switch -- $merge_type {
                ff {
-                       if {$mrb eq $new} {
+                       if {$merge_base eq $new} {
                                # The current branch is actually newer.
                                #
                                set new $cur
-                       } elseif {$mrb eq $cur} {
+                       } elseif {$merge_base eq $cur} {
                                # The current branch is older.
                                #
                                set reflog_msg "merge $new_expr: Fast-forward"
@@ -198,7 +198,7 @@ method _update_ref {} {
                        }
                }
                reset {
-                       if {$mrb eq $cur} {
+                       if {$merge_base eq $cur} {
                                # The current branch is older.
                                #
                                set reflog_msg "merge $new_expr: Fast-forward"