rebase: add rebase.updateRefs config option

The previous change added the --update-refs command-line option.  For
users who always want this mode, create the rebase.updateRefs config
option which behaves the same way as rebase.autoSquash does with the
--autosquash option.

Signed-off-by: Derrick Stolee <derrickstolee@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/config/rebase.txt

@@ -21,6 +21,9 @@ rebase.autoStash::
 	`--autostash` options of linkgit:git-rebase[1].
 	Defaults to false.
 
+rebase.updateRefs::
+	If set to true enable `--update-refs` option by default.
+
 rebase.missingCommitsCheck::
 	If set to "warn", git rebase -i will print a warning if some
 	commits are removed (e.g. a line was deleted), however the

Documentation/git-rebase.txt

@@ -614,6 +614,9 @@ start would be overridden by the presence of
 	Automatically force-update any branches that point to commits that
 	are being rebased. Any branches that are checked out in a worktree
 	are not updated in this way.
++
+If the configuration variable `rebase.updateRefs` is set, then this option
+can be used to override and disable this setting.
 
 INCOMPATIBLE OPTIONS
 --------------------

builtin/rebase.c

@@ -802,6 +802,11 @@ static int rebase_config(const char *var, const char *value, void *data)
 		return 0;
 	}
 
+	if (!strcmp(var, "rebase.updaterefs")) {
+		opts->update_refs = git_config_bool(var, value);
+		return 0;
+	}
+
 	if (!strcmp(var, "rebase.reschedulefailedexec")) {
 		opts->reschedule_failed_exec = git_config_bool(var, value);
 		return 0;

t/t3404-rebase-interactive.sh

@@ -1772,6 +1772,12 @@ test_expect_success '--update-refs adds label and update-ref commands' '
 		EOF
 
 		test_must_fail git rebase -i --autosquash --update-refs primary >todo &&
+		test_cmp expect todo &&
+
+		test_must_fail git -c rebase.autosquash=true \
+				   -c rebase.updaterefs=true \
+				   rebase -i primary >todo &&
+
 		test_cmp expect todo
 	)
 '
@@ -1813,6 +1819,14 @@ test_expect_success '--update-refs adds commands with --rebase-merges' '
 				   --rebase-merges=rebase-cousins \
 				   --update-refs primary >todo &&
 
+		test_cmp expect todo &&
+
+		test_must_fail git -c rebase.autosquash=true \
+				   -c rebase.updaterefs=true \
+				   rebase -i \
+				   --rebase-merges=rebase-cousins \
+				   primary >todo &&
+
 		test_cmp expect todo
 	)
 '