rebase --exec: make it work with --rebase-merges

The idea of `--exec` is to append an `exec` call after each `pick`.

Since the introduction of fixup!/squash! commits, this idea was extended
to apply to "pick, possibly followed by a fixup/squash chain", i.e. an
exec would not be inserted between a `pick` and any of its corresponding
`fixup` or `squash` lines.

The current implementation uses a dirty trick to achieve that: it
assumes that there are only pick/fixup/squash commands, and then
*inserts* the `exec` lines before any `pick` but the first, and appends
a final one.

With the todo lists generated by `git rebase --rebase-merges`, this
simple implementation shows its problems: it produces the exact wrong
thing when there are `label`, `reset` and `merge` commands.

Let's change the implementation to do exactly what we want: look for
`pick` lines, skip any fixup/squash chains, and then insert the `exec`
line. Lather, rinse, repeat.

Note: we take pains to insert *before* comment lines whenever possible,
as empty commits are represented by commented-out pick lines (and we
want to insert a preceding pick's exec line *before* such a line, not
afterward).

While at it, also add `exec` lines after `merge` commands, because they
are similar in spirit to `pick` commands: they add new commits.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/sequencer.c b/sequencer.c
index 31038472fdc0f13e820c43b32cf2e1448b54a543..278d34ce9d6006bee42dfb115dd2b2fbf13b2897 100644 (file)
--- a/sequencer.c
+++ b/sequencer.c
@@ -4244,10 +4244,9 @@ int sequencer_add_exec_commands(const char *commands)
 {
        const char *todo_file = rebase_path_todo();
        struct todo_list todo_list = TODO_LIST_INIT;
-       struct todo_item *item;
        struct strbuf *buf = &todo_list.buf;
        size_t offset = 0, commands_len = strlen(commands);
-       int i, first;
+       int i, insert;
 
        if (strbuf_read_file(&todo_list.buf, todo_file, 0) < 0)
                return error(_("could not read '%s'."), todo_file);
@@ -4257,19 +4256,40 @@ int sequencer_add_exec_commands(const char *commands)
                return error(_("unusable todo list: '%s'"), todo_file);
        }
 
-       first = 1;
-       /* insert <commands> before every pick except the first one */
-       for (item = todo_list.items, i = 0; i < todo_list.nr; i++, item++) {
-               if (item->command == TODO_PICK && !first) {
-                       strbuf_insert(buf, item->offset_in_buf + offset,
-                                     commands, commands_len);
+       /*
+        * Insert <commands> after every pick. Here, fixup/squash chains
+        * are considered part of the pick, so we insert the commands *after*
+        * those chains if there are any.
+        */
+       insert = -1;
+       for (i = 0; i < todo_list.nr; i++) {
+               enum todo_command command = todo_list.items[i].command;
+
+               if (insert >= 0) {
+                       /* skip fixup/squash chains */
+                       if (command == TODO_COMMENT)
+                               continue;
+                       else if (is_fixup(command)) {
+                               insert = i + 1;
+                               continue;
+                       }
+                       strbuf_insert(buf,
+                                     todo_list.items[insert].offset_in_buf +
+                                     offset, commands, commands_len);
                        offset += commands_len;
+                       insert = -1;
                }
-               first = 0;
+
+               if (command == TODO_PICK || command == TODO_MERGE)
+                       insert = i + 1;
        }
 
-       /* append final <commands> */
-       strbuf_add(buf, commands, commands_len);
+       /* insert or append final <commands> */
+       if (insert >= 0 && insert < todo_list.nr)
+               strbuf_insert(buf, todo_list.items[insert].offset_in_buf +
+                             offset, commands, commands_len);
+       else if (insert >= 0 || !offset)
+               strbuf_add(buf, commands, commands_len);
 
        i = write_message(buf->buf, buf->len, todo_file, 0);
        todo_list_release(&todo_list);

diff --git a/t/t3430-rebase-merges.sh b/t/t3430-rebase-merges.sh
index 0bf5eaa376be2749297c56c31c9aa744ea46b90b..90ae613e23fb5bbbde638c25dd052d398169fba6 100755 (executable)
--- a/t/t3430-rebase-merges.sh
+++ b/t/t3430-rebase-merges.sh
@@ -363,7 +363,7 @@ test_expect_success 'octopus merges' '
        EOF
 '
 
-test_expect_failure 'with --autosquash and --exec' '
+test_expect_success 'with --autosquash and --exec' '
        git checkout -b with-exec H &&
        echo Booh >B.t &&
        test_tick &&