bisect: rework some rev related functions to make them more reusable
[gitweb.git] / bisect.c
index d2a34d1e5175a19babe5c0194308254279951b04..dc4e1bb3c430328c27ed1a5580c3d3cd8be6d294 100644 (file)
--- a/bisect.c
+++ b/bisect.c
@@ -507,6 +507,20 @@ static int lookup_sha1_array(struct sha1_array *array,
        return sha1_pos(sha1, array->sha1, array->sha1_nr, sha1_access);
 }
 
+static char *join_sha1_array_hex(struct sha1_array *array, char delim)
+{
+       struct strbuf joined_hexs = STRBUF_INIT;
+       int i;
+
+       for (i = 0; i < array->sha1_nr; i++) {
+               strbuf_addstr(&joined_hexs, sha1_to_hex(array->sha1[i]));
+               if (i + 1 < array->sha1_nr)
+                       strbuf_addch(&joined_hexs, delim);
+       }
+
+       return strbuf_detach(&joined_hexs, NULL);
+}
+
 struct commit_list *filter_skipped(struct commit_list *list,
                                   struct commit_list **tried,
                                   int show_all)
@@ -539,7 +553,9 @@ struct commit_list *filter_skipped(struct commit_list *list,
        return filtered;
 }
 
-static void bisect_rev_setup(struct rev_info *revs, const char *prefix)
+static void bisect_rev_setup(struct rev_info *revs, const char *prefix,
+                            const char *bad_format, const char *good_format,
+                            int read_paths)
 {
        struct argv_array rev_argv = { NULL, 0, 0 };
        int i;
@@ -550,26 +566,24 @@ static void bisect_rev_setup(struct rev_info *revs, const char *prefix)
 
        /* rev_argv.argv[0] will be ignored by setup_revisions */
        argv_array_push(&rev_argv, xstrdup("bisect_rev_setup"));
-       argv_array_push_sha1(&rev_argv, current_bad_sha1, "%s");
+       argv_array_push_sha1(&rev_argv, current_bad_sha1, bad_format);
        for (i = 0; i < good_revs.sha1_nr; i++)
-               argv_array_push_sha1(&rev_argv, good_revs.sha1[i], "^%s");
+               argv_array_push_sha1(&rev_argv, good_revs.sha1[i],
+                                    good_format);
        argv_array_push(&rev_argv, xstrdup("--"));
-       read_bisect_paths(&rev_argv);
+       if (read_paths)
+               read_bisect_paths(&rev_argv);
        argv_array_push(&rev_argv, NULL);
 
        setup_revisions(rev_argv.argv_nr, rev_argv.argv, revs, NULL);
-       revs->limited = 1;
 }
 
-static void bisect_common(struct rev_info *revs, int *reaches, int *all)
+static void bisect_common(struct rev_info *revs)
 {
        if (prepare_revision_walk(revs))
                die("revision walk setup failed");
        if (revs->tree_objects)
                mark_edges_uninteresting(revs->commits, revs, NULL);
-
-       revs->commits = find_bisection(revs->commits, reaches, all,
-                                      !!skipped_revs.sha1_nr);
 }
 
 static void exit_if_skipped_commits(struct commit_list *tried,
@@ -587,6 +601,30 @@ static void exit_if_skipped_commits(struct commit_list *tried,
        exit(2);
 }
 
+static int is_expected_rev(const unsigned char *sha1)
+{
+       const char *filename = git_path("BISECT_EXPECTED_REV");
+       struct stat st;
+       struct strbuf str = STRBUF_INIT;
+       FILE *fp;
+       int res = 0;
+
+       if (stat(filename, &st) || !S_ISREG(st.st_mode))
+               return 0;
+
+       fp = fopen(filename, "r");
+       if (!fp)
+               return 0;
+
+       if (strbuf_getline(&str, fp, '\n') != EOF)
+               res = !strcmp(str.buf, sha1_to_hex(sha1));
+
+       strbuf_release(&str);
+       fclose(fp);
+
+       return res;
+}
+
 static void mark_expected_rev(char *bisect_rev_hex)
 {
        int len = strlen(bisect_rev_hex);
@@ -620,12 +658,179 @@ static int bisect_checkout(char *bisect_rev_hex)
        return run_command_v_opt(argv_show_branch, RUN_GIT_CMD);
 }
 
+static struct commit *get_commit_reference(const unsigned char *sha1)
+{
+       struct commit *r = lookup_commit_reference(sha1);
+       if (!r)
+               die("Not a valid commit name %s", sha1_to_hex(sha1));
+       return r;
+}
+
+static struct commit **get_bad_and_good_commits(int *rev_nr)
+{
+       int len = 1 + good_revs.sha1_nr;
+       struct commit **rev = xmalloc(len * sizeof(*rev));
+       int i, n = 0;
+
+       rev[n++] = get_commit_reference(current_bad_sha1);
+       for (i = 0; i < good_revs.sha1_nr; i++)
+               rev[n++] = get_commit_reference(good_revs.sha1[i]);
+       *rev_nr = n;
+
+       return rev;
+}
+
+static void handle_bad_merge_base(void)
+{
+       if (is_expected_rev(current_bad_sha1)) {
+               char *bad_hex = sha1_to_hex(current_bad_sha1);
+               char *good_hex = join_sha1_array_hex(&good_revs, ' ');
+
+               fprintf(stderr, "The merge base %s is bad.\n"
+                       "This means the bug has been fixed "
+                       "between %s and [%s].\n",
+                       bad_hex, bad_hex, good_hex);
+
+               exit(3);
+       }
+
+       fprintf(stderr, "Some good revs are not ancestor of the bad rev.\n"
+               "git bisect cannot work properly in this case.\n"
+               "Maybe you mistake good and bad revs?\n");
+       exit(1);
+}
+
+void handle_skipped_merge_base(const unsigned char *mb)
+{
+       char *mb_hex = sha1_to_hex(mb);
+       char *bad_hex = sha1_to_hex(current_bad_sha1);
+       char *good_hex = join_sha1_array_hex(&good_revs, ' ');
+
+       fprintf(stderr, "Warning: the merge base between %s and [%s] "
+               "must be skipped.\n"
+               "So we cannot be sure the first bad commit is "
+               "between %s and %s.\n"
+               "We continue anyway.\n",
+               bad_hex, good_hex, mb_hex, bad_hex);
+       free(good_hex);
+}
+
+/*
+ * "check_merge_bases" checks that merge bases are not "bad".
+ *
+ * - If one is "bad", it means the user assumed something wrong
+ * and we must exit with a non 0 error code.
+ * - If one is "good", that's good, we have nothing to do.
+ * - 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)
+{
+       struct commit_list *result;
+       int rev_nr;
+       struct commit **rev = get_bad_and_good_commits(&rev_nr);
+
+       result = get_merge_bases_many(rev[0], rev_nr - 1, rev + 1, 0);
+
+       for (; result; result = result->next) {
+               const unsigned char *mb = result->item->object.sha1;
+               if (!hashcmp(mb, current_bad_sha1)) {
+                       handle_bad_merge_base();
+               } else if (0 <= lookup_sha1_array(&good_revs, mb)) {
+                       continue;
+               } else if (0 <= lookup_sha1_array(&skipped_revs, mb)) {
+                       handle_skipped_merge_base(mb);
+               } else {
+                       printf("Bisecting: a merge base must be tested\n");
+                       exit(bisect_checkout(sha1_to_hex(mb)));
+               }
+       }
+
+       free(rev);
+       free_commit_list(result);
+}
+
+/*
+ * This function runs the command "git rev-list $_good ^$_bad"
+ * and returns 1 if it produces some output, 0 otherwise.
+ */
+static int check_ancestors(void)
+{
+       struct argv_array rev_argv = { NULL, 0, 0 };
+       struct strbuf str = STRBUF_INIT;
+       int i, result = 0;
+       struct child_process rls;
+       FILE *rls_fout;
+
+       argv_array_push(&rev_argv, xstrdup("rev-list"));
+       argv_array_push_sha1(&rev_argv, current_bad_sha1, "^%s");
+       for (i = 0; i < good_revs.sha1_nr; i++)
+               argv_array_push_sha1(&rev_argv, good_revs.sha1[i], "%s");
+       argv_array_push(&rev_argv, NULL);
+
+       memset(&rls, 0, sizeof(rls));
+       rls.argv = rev_argv.argv;
+       rls.out = -1;
+       rls.git_cmd = 1;
+       if (start_command(&rls))
+               die("Could not launch 'git rev-list' command.");
+       rls_fout = fdopen(rls.out, "r");
+       while (strbuf_getline(&str, rls_fout, '\n') != EOF) {
+               strbuf_trim(&str);
+               if (*str.buf) {
+                       result = 1;
+                       break;
+               }
+       }
+       fclose(rls_fout);
+       finish_command(&rls);
+
+       return result;
+}
+
+/*
+ * "check_good_are_ancestors_of_bad" checks that all "good" revs are
+ * ancestor of the "bad" rev.
+ *
+ * If that's not the case, we need to check the merge bases.
+ * 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)
+{
+       const char *filename = git_path("BISECT_ANCESTORS_OK");
+       struct stat st;
+       int fd;
+
+       if (!current_bad_sha1)
+               die("a bad revision is needed");
+
+       /* Check if file BISECT_ANCESTORS_OK exists. */
+       if (!stat(filename, &st) && S_ISREG(st.st_mode))
+               return;
+
+       /* Bisecting with no good rev is ok. */
+       if (good_revs.sha1_nr == 0)
+               return;
+
+       if (check_ancestors())
+               check_merge_bases();
+
+       /* Create file BISECT_ANCESTORS_OK. */
+       fd = open(filename, O_CREAT | O_TRUNC | O_WRONLY, 0600);
+       if (fd < 0)
+               warning("could not create file '%s': %s",
+                       filename, strerror(errno));
+       else
+               close(fd);
+}
+
 /*
  * 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.
  */
-int bisect_next_exit(const char *prefix)
+int bisect_next_all(const char *prefix)
 {
        struct rev_info revs;
        struct commit_list *tried;
@@ -636,10 +841,15 @@ int bisect_next_exit(const char *prefix)
        if (read_bisect_refs())
                die("reading bisect refs failed");
 
-       bisect_rev_setup(&revs, prefix);
+       check_good_are_ancestors_of_bad(prefix);
 
-       bisect_common(&revs, &reaches, &all);
+       bisect_rev_setup(&revs, prefix, "%s", "^%s", 1);
+       revs.limited = 1;
 
+       bisect_common(&revs);
+
+       revs.commits = find_bisection(revs.commits, &reaches, &all,
+                                      !!skipped_revs.sha1_nr);
        revs.commits = filter_skipped(revs.commits, &tried, 0);
 
        if (!revs.commits) {