bisect: introduce support for --no-checkout option.

If --no-checkout is specified, then the bisection process uses:

	git update-ref --no-deref HEAD <trial>

at each trial instead of:

	git checkout <trial>

Improved-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Jon Seymour <jon.seymour@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/bisect.c b/bisect.c
index dd7e8ed69bc0c1268dc3b0a6590501ba9c10d7db..c7b7d7913dc444926b0260211e8bc3aa75eeffdb 100644 (file)
--- a/bisect.c
+++ b/bisect.c
@@ -24,6 +24,7 @@ struct argv_array {
 
 static const char *argv_checkout[] = {"checkout", "-q", NULL, "--", NULL};
 static const char *argv_show_branch[] = {"show-branch", NULL, NULL};
+static const char *argv_update_ref[] = {"update-ref", "--no-deref", "BISECT_HEAD", NULL, NULL};
 
 /* bits #0-15 in revision.h */
 
@@ -707,16 +708,23 @@ static void mark_expected_rev(char *bisect_rev_hex)
                die("closing file %s: %s", filename, strerror(errno));
 }
 
-static int bisect_checkout(char *bisect_rev_hex)
+static int bisect_checkout(char *bisect_rev_hex, int no_checkout)
 {
        int res;
 
        mark_expected_rev(bisect_rev_hex);
 
        argv_checkout[2] = bisect_rev_hex;
-       res = run_command_v_opt(argv_checkout, RUN_GIT_CMD);
-       if (res)
-               exit(res);
+       if (no_checkout) {
+               argv_update_ref[3] = bisect_rev_hex;
+               if (run_command_v_opt(argv_update_ref, RUN_GIT_CMD))
+                       die("update-ref --no-deref HEAD failed on %s",
+                           bisect_rev_hex);
+       } else {
+               res = run_command_v_opt(argv_checkout, RUN_GIT_CMD);
+               if (res)
+                       exit(res);
+       }
 
        argv_show_branch[1] = bisect_rev_hex;
        return run_command_v_opt(argv_show_branch, RUN_GIT_CMD);
@@ -788,7 +796,7 @@ static void handle_skipped_merge_base(const unsigned char *mb)
  * - If one is "skipped", we can't know but we should warn.
  * - If we don't know, we should check it out and ask the user to test.
  */
-static void check_merge_bases(void)
+static void check_merge_bases(int no_checkout)
 {
        struct commit_list *result;
        int rev_nr;
@@ -806,7 +814,7 @@ static void check_merge_bases(void)
                        handle_skipped_merge_base(mb);
                } else {
                        printf("Bisecting: a merge base must be tested\n");
-                       exit(bisect_checkout(sha1_to_hex(mb)));
+                       exit(bisect_checkout(sha1_to_hex(mb), no_checkout));
                }
        }
 
@@ -849,7 +857,7 @@ static int check_ancestors(const char *prefix)
  * If a merge base must be tested by the user, its source code will be
  * checked out to be tested by the user and we will exit.
  */
-static void check_good_are_ancestors_of_bad(const char *prefix)
+static void check_good_are_ancestors_of_bad(const char *prefix, int no_checkout)
 {
        const char *filename = git_path("BISECT_ANCESTORS_OK");
        struct stat st;
@@ -868,7 +876,7 @@ static void check_good_are_ancestors_of_bad(const char *prefix)
 
        /* Check if all good revs are ancestor of the bad rev. */
        if (check_ancestors(prefix))
-               check_merge_bases();
+               check_merge_bases(no_checkout);
 
        /* Create file BISECT_ANCESTORS_OK. */
        fd = open(filename, O_CREAT | O_TRUNC | O_WRONLY, 0600);
@@ -908,8 +916,11 @@ static void show_diff_tree(const char *prefix, struct commit *commit)
  * We use the convention that exiting with an exit code 10 means that
  * the bisection process finished successfully.
  * In this case the calling shell script should exit 0.
+ *
+ * If no_checkout is non-zero, the bisection process does not
+ * checkout the trial commit but instead simply updates BISECT_HEAD.
  */
-int bisect_next_all(const char *prefix)
+int bisect_next_all(const char *prefix, int no_checkout)
 {
        struct rev_info revs;
        struct commit_list *tried;
@@ -920,7 +931,7 @@ int bisect_next_all(const char *prefix)
        if (read_bisect_refs())
                die("reading bisect refs failed");
 
-       check_good_are_ancestors_of_bad(prefix);
+       check_good_are_ancestors_of_bad(prefix, no_checkout);
 
        bisect_rev_setup(&revs, prefix, "%s", "^%s", 1);
        revs.limited = 1;
@@ -966,6 +977,6 @@ int bisect_next_all(const char *prefix)
               "(roughly %d step%s)\n", nr, (nr == 1 ? "" : "s"),
               steps, (steps == 1 ? "" : "s"));
 
-       return bisect_checkout(bisect_rev_hex);
+       return bisect_checkout(bisect_rev_hex, no_checkout);
 }
 

diff --git a/bisect.h b/bisect.h
index 0862ce56d76e9b08ab913e6a472fac590974340e..22f2e4db2d1d05184dc2eeec2ff87021a67e01f2 100644 (file)
--- a/bisect.h
+++ b/bisect.h
@@ -27,7 +27,7 @@ struct rev_list_info {
        const char *header_prefix;
 };
 
-extern int bisect_next_all(const char *prefix);
+extern int bisect_next_all(const char *prefix, int no_checkout);
 
 extern int estimate_bisect_steps(int all);
 

diff --git a/builtin/bisect--helper.c b/builtin/bisect--helper.c
index 5b226399e1c30b23a7b5d226a3f45efe9dbedf45..8d325a5179f68d2810b5b2082fe66dc6d00da455 100644 (file)
--- a/builtin/bisect--helper.c
+++ b/builtin/bisect--helper.c
@@ -4,16 +4,19 @@
 #include "bisect.h"
 
 static const char * const git_bisect_helper_usage[] = {
-       "git bisect--helper --next-all",
+       "git bisect--helper --next-all [--no-checkout]",
        NULL
 };
 
 int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 {
        int next_all = 0;
+       int no_checkout = 0;
        struct option options[] = {
                OPT_BOOLEAN(0, "next-all", &next_all,
                            "perform 'git bisect next'"),
+               OPT_BOOLEAN(0, "no-checkout", &no_checkout,
+                           "update BISECT_HEAD instead of checking out the current commit"),
                OPT_END()
        };
 
@@ -24,5 +27,5 @@ int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
                usage_with_options(git_bisect_helper_usage, options);
 
        /* next-all */
-       return bisect_next_all(prefix);
+       return bisect_next_all(prefix, no_checkout);
 }