Merge branch 'rr/maint-t3510-cascade-fix'
[gitweb.git] / sequencer.c
index cd11e340dda2d3905df84d9187f70226affef08f..bf078f274bfe23997fcd1bc8c2a1c958f39ac9fe 100644 (file)
@@ -13,6 +13,7 @@
 #include "rerere.h"
 #include "merge-recursive.h"
 #include "refs.h"
+#include "argv-array.h"
 
 #define GIT_REFLOG_ACTION "GIT_REFLOG_ACTION"
 
@@ -251,6 +252,38 @@ static int do_recursive_merge(struct commit *base, struct commit *next,
        return !clean;
 }
 
+static int is_index_unchanged(void)
+{
+       unsigned char head_sha1[20];
+       struct commit *head_commit;
+
+       if (!resolve_ref_unsafe("HEAD", head_sha1, 1, NULL))
+               return error(_("Could not resolve HEAD commit\n"));
+
+       head_commit = lookup_commit(head_sha1);
+
+       /*
+        * If head_commit is NULL, check_commit, called from
+        * lookup_commit, would have indicated that head_commit is not
+        * a commit object already.  parse_commit() will return failure
+        * without further complaints in such a case.  Otherwise, if
+        * the commit is invalid, parse_commit() will complain.  So
+        * there is nothing for us to say here.  Just return failure.
+        */
+       if (parse_commit(head_commit))
+               return -1;
+
+       if (!active_cache_tree)
+               active_cache_tree = cache_tree();
+
+       if (!cache_tree_fully_valid(active_cache_tree))
+               if (cache_tree_update(active_cache_tree, active_cache,
+                                 active_nr, 0))
+                       return error(_("Unable to update cache tree\n"));
+
+       return !hashcmp(active_cache_tree->sha1, head_commit->tree->object.sha1);
+}
+
 /*
  * If we are cherry-pick, and if the merge did not result in
  * hand-editing, we will hit this commit and inherit the original
@@ -258,23 +291,87 @@ static int do_recursive_merge(struct commit *base, struct commit *next,
  * If we are revert, or if our cherry-pick results in a hand merge,
  * we had better say that the current user is responsible for that.
  */
-static int run_git_commit(const char *defmsg, struct replay_opts *opts)
+static int run_git_commit(const char *defmsg, struct replay_opts *opts,
+                         int allow_empty)
 {
-       /* 6 is max possible length of our args array including NULL */
-       const char *args[6];
-       int i = 0;
+       struct argv_array array;
+       int rc;
+
+       argv_array_init(&array);
+       argv_array_push(&array, "commit");
+       argv_array_push(&array, "-n");
 
-       args[i++] = "commit";
-       args[i++] = "-n";
        if (opts->signoff)
-               args[i++] = "-s";
+               argv_array_push(&array, "-s");
        if (!opts->edit) {
-               args[i++] = "-F";
-               args[i++] = defmsg;
+               argv_array_push(&array, "-F");
+               argv_array_push(&array, defmsg);
+       }
+
+       if (allow_empty)
+               argv_array_push(&array, "--allow-empty");
+
+       rc = run_command_v_opt(array.argv, RUN_GIT_CMD);
+       argv_array_clear(&array);
+       return rc;
+}
+
+static int is_original_commit_empty(struct commit *commit)
+{
+       const unsigned char *ptree_sha1;
+
+       if (parse_commit(commit))
+               return error(_("Could not parse commit %s\n"),
+                            sha1_to_hex(commit->object.sha1));
+       if (commit->parents) {
+               struct commit *parent = commit->parents->item;
+               if (parse_commit(parent))
+                       return error(_("Could not parse parent commit %s\n"),
+                               sha1_to_hex(parent->object.sha1));
+               ptree_sha1 = parent->tree->object.sha1;
+       } else {
+               ptree_sha1 = EMPTY_TREE_SHA1_BIN; /* commit is root */
        }
-       args[i] = NULL;
 
-       return run_command_v_opt(args, RUN_GIT_CMD);
+       return !hashcmp(ptree_sha1, commit->tree->object.sha1);
+}
+
+/*
+ * Do we run "git commit" with "--allow-empty"?
+ */
+static int allow_empty(struct replay_opts *opts, struct commit *commit)
+{
+       int index_unchanged, empty_commit;
+
+       /*
+        * Three cases:
+        *
+        * (1) we do not allow empty at all and error out.
+        *
+        * (2) we allow ones that were initially empty, but
+        * forbid the ones that become empty;
+        *
+        * (3) we allow both.
+        */
+       if (!opts->allow_empty)
+               return 0; /* let "git commit" barf as necessary */
+
+       index_unchanged = is_index_unchanged();
+       if (index_unchanged < 0)
+               return index_unchanged;
+       if (!index_unchanged)
+               return 0; /* we do not have to say --allow-empty */
+
+       if (opts->keep_redundant_commits)
+               return 1;
+
+       empty_commit = is_original_commit_empty(commit);
+       if (empty_commit < 0)
+               return empty_commit;
+       if (!empty_commit)
+               return 0;
+       else
+               return 1;
 }
 
 static int do_pick_commit(struct commit *commit, struct replay_opts *opts)
@@ -431,8 +528,11 @@ static int do_pick_commit(struct commit *commit, struct replay_opts *opts)
                print_advice(res == 1, opts);
                rerere(opts->allow_rerere_auto);
        } else {
+               int allow = allow_empty(opts, commit);
+               if (allow < 0)
+                       return allow;
                if (!opts->no_commit)
-                       res = run_git_commit(defmsg, opts);
+                       res = run_git_commit(defmsg, opts, allow);
        }
 
        free_message(&msg);
@@ -468,33 +568,6 @@ static void read_and_refresh_cache(struct replay_opts *opts)
        rollback_lock_file(&index_lock);
 }
 
-/*
- * Append a commit to the end of the commit_list.
- *
- * next starts by pointing to the variable that holds the head of an
- * empty commit_list, and is updated to point to the "next" field of
- * the last item on the list as new commits are appended.
- *
- * Usage example:
- *
- *     struct commit_list *list;
- *     struct commit_list **next = &list;
- *
- *     next = commit_list_append(c1, next);
- *     next = commit_list_append(c2, next);
- *     assert(commit_list_count(list) == 2);
- *     return list;
- */
-static struct commit_list **commit_list_append(struct commit *commit,
-                                              struct commit_list **next)
-{
-       struct commit_list *new = xmalloc(sizeof(struct commit_list));
-       new->item = commit;
-       *next = new;
-       new->next = NULL;
-       return &new->next;
-}
-
 static int format_todo(struct strbuf *buf, struct commit_list *todo_list,
                struct replay_opts *opts)
 {