Fix various sparse warnings in the git source code
[gitweb.git] / bisect.c
index d2a34d1e5175a19babe5c0194308254279951b04..dbeb28752adce639d8729fa7cbb003fc31bd240f 100644 (file)
--- a/bisect.c
+++ b/bisect.c
@@ -7,6 +7,7 @@
 #include "quote.h"
 #include "sha1-lookup.h"
 #include "run-command.h"
+#include "log-tree.h"
 #include "bisect.h"
 
 struct sha1_array {
@@ -27,7 +28,6 @@ struct argv_array {
        int argv_alloc;
 };
 
-static const char *argv_diff_tree[] = {"diff-tree", "--pretty", NULL, NULL};
 static const char *argv_checkout[] = {"checkout", "-q", NULL, "--", NULL};
 static const char *argv_show_branch[] = {"show-branch", NULL, NULL};
 
@@ -454,7 +454,7 @@ static int read_bisect_refs(void)
        return for_each_ref_in("refs/bisect/", register_ref, NULL);
 }
 
-void read_bisect_paths(struct argv_array *array)
+static void read_bisect_paths(struct argv_array *array)
 {
        struct strbuf str = STRBUF_INIT;
        const char *filename = git_path("BISECT_NAMES");
@@ -507,14 +507,48 @@ 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);
+}
+
+/*
+ * In this function, passing a not NULL skipped_first is very special.
+ * It means that we want to know if the first commit in the list is
+ * skipped because we will want to test a commit away from it if it is
+ * indeed skipped.
+ * So if the first commit is skipped, we cannot take the shortcut to
+ * just "return list" when we find the first non skipped commit, we
+ * have to return a fully filtered list.
+ *
+ * We use (*skipped_first == -1) to mean "it has been found that the
+ * first commit is not skipped". In this case *skipped_first is set back
+ * to 0 just before the function returns.
+ */
 struct commit_list *filter_skipped(struct commit_list *list,
                                   struct commit_list **tried,
-                                  int show_all)
+                                  int show_all,
+                                  int *count,
+                                  int *skipped_first)
 {
        struct commit_list *filtered = NULL, **f = &filtered;
 
        *tried = NULL;
 
+       if (skipped_first)
+               *skipped_first = 0;
+       if (count)
+               *count = 0;
+
        if (!skipped_revs.sha1_nr)
                return list;
 
@@ -523,23 +557,85 @@ struct commit_list *filter_skipped(struct commit_list *list,
                list->next = NULL;
                if (0 <= lookup_sha1_array(&skipped_revs,
                                           list->item->object.sha1)) {
+                       if (skipped_first && !*skipped_first)
+                               *skipped_first = 1;
                        /* Move current to tried list */
                        *tried = list;
                        tried = &list->next;
                } else {
-                       if (!show_all)
-                               return list;
+                       if (!show_all) {
+                               if (!skipped_first || !*skipped_first)
+                                       return list;
+                       } else if (skipped_first && !*skipped_first) {
+                               /* This means we know it's not skipped */
+                               *skipped_first = -1;
+                       }
                        /* Move current to filtered list */
                        *f = list;
                        f = &list->next;
+                       if (count)
+                               (*count)++;
                }
                list = next;
        }
 
+       if (skipped_first && *skipped_first == -1)
+               *skipped_first = 0;
+
        return filtered;
 }
 
-static void bisect_rev_setup(struct rev_info *revs, const char *prefix)
+static struct commit_list *apply_skip_ratio(struct commit_list *list,
+                                           int count,
+                                           int skip_num, int skip_denom)
+{
+       int index, i;
+       struct commit_list *cur, *previous;
+
+       cur = list;
+       previous = NULL;
+       index = count * skip_num / skip_denom;
+
+       for (i = 0; cur; cur = cur->next, i++) {
+               if (i == index) {
+                       if (hashcmp(cur->item->object.sha1, current_bad_sha1))
+                               return cur;
+                       if (previous)
+                               return previous;
+                       return list;
+               }
+               previous = cur;
+       }
+
+       return list;
+}
+
+static struct commit_list *managed_skipped(struct commit_list *list,
+                                          struct commit_list **tried)
+{
+       int count, skipped_first;
+       int skip_num, skip_denom;
+
+       *tried = NULL;
+
+       if (!skipped_revs.sha1_nr)
+               return list;
+
+       list = filter_skipped(list, tried, 0, &count, &skipped_first);
+
+       if (!skipped_first)
+               return list;
+
+       /* Use alternatively 1/5, 2/5 and 3/5 as skip ratio. */
+       skip_num = count % 3 + 1;
+       skip_denom = 5;
+
+       return apply_skip_ratio(list, count, skip_num, skip_denom);
+}
+
+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 +646,24 @@ 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 +681,30 @@ 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 +738,194 @@ 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);
+}
+
+static 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);
+}
+
+static int check_ancestors(const char *prefix)
+{
+       struct rev_info revs;
+       struct object_array pending_copy;
+       int i, res;
+
+       bisect_rev_setup(&revs, prefix, "^%s", "%s", 0);
+
+       /* Save pending objects, so they can be cleaned up later. */
+       memset(&pending_copy, 0, sizeof(pending_copy));
+       for (i = 0; i < revs.pending.nr; i++)
+               add_object_array(revs.pending.objects[i].item,
+                                revs.pending.objects[i].name,
+                                &pending_copy);
+
+       bisect_common(&revs);
+       res = (revs.commits != NULL);
+
+       /* Clean up objects used, as they will be reused. */
+       for (i = 0; i < pending_copy.nr; i++) {
+               struct object *o = pending_copy.objects[i].item;
+               clear_commit_marks((struct commit *)o, ALL_REV_FLAGS);
+       }
+
+       return res;
+}
+
+/*
+ * "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;
+
+       /* Check if all good revs are ancestor of the bad rev. */
+       if (check_ancestors(prefix))
+               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);
+}
+
+/*
+ * This does "git diff-tree --pretty COMMIT" without one fork+exec.
+ */
+static void show_diff_tree(const char *prefix, struct commit *commit)
+{
+       struct rev_info opt;
+
+       /* diff-tree init */
+       init_revisions(&opt, prefix);
+       git_config(git_diff_basic_config, NULL); /* no "diff" UI options */
+       opt.abbrev = 0;
+       opt.diff = 1;
+
+       /* This is what "--pretty" does */
+       opt.verbose_header = 1;
+       opt.use_terminator = 0;
+       opt.commit_format = CMIT_FMT_DEFAULT;
+
+       /* diff-tree init */
+       if (!opt.diffopt.output_format)
+               opt.diffopt.output_format = DIFF_FORMAT_RAW;
+
+       log_tree_commit(&opt, 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.
  */
-int bisect_next_exit(const char *prefix)
+int bisect_next_all(const char *prefix)
 {
        struct rev_info revs;
        struct commit_list *tried;
@@ -636,11 +936,16 @@ 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_rev_setup(&revs, prefix, "%s", "^%s", 1);
+       revs.limited = 1;
 
-       bisect_common(&revs, &reaches, &all);
+       bisect_common(&revs);
 
-       revs.commits = filter_skipped(revs.commits, &tried, 0);
+       revs.commits = find_bisection(revs.commits, &reaches, &all,
+                                      !!skipped_revs.sha1_nr);
+       revs.commits = managed_skipped(revs.commits, &tried);
 
        if (!revs.commits) {
                /*
@@ -660,8 +965,7 @@ int bisect_next_exit(const char *prefix)
        if (!hashcmp(bisect_rev, current_bad_sha1)) {
                exit_if_skipped_commits(tried, current_bad_sha1);
                printf("%s is first bad commit\n", bisect_rev_hex);
-               argv_diff_tree[2] = bisect_rev_hex;
-               run_command_v_opt(argv_diff_tree, RUN_GIT_CMD);
+               show_diff_tree(prefix, revs.commits->item);
                /* This means the bisection process succeeded. */
                exit(10);
        }