rebase: fix incompatiblity checks for --[no-]reapply-cherry-picks

--[no-]reapply-cherry-picks was traditionally only supported by the
sequencer.  Support was added for the apply backend, when --keep-base is
also specified, in commit ce5238a690 ("rebase --keep-base: imply
--reapply-cherry-picks", 2022-10-17).  Make the code error out when
--[no-]reapply-cherry-picks is specified AND the apply backend is used
AND --keep-base is not specified.  Also, clarify a number of comments
surrounding the interaction of these flags.

Helped-by: Phillip Wood <phillip.wood@dunelm.org.uk>
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/Documentation/git-rebase.txt b/Documentation/git-rebase.txt
index 846aeed1b69196f41356688cdf2319fd3c0f5eb4..8a09f12d897fac7069126cb444962dced92f81d4 100644 (file)
--- a/Documentation/git-rebase.txt
+++ b/Documentation/git-rebase.txt
@@ -650,7 +650,7 @@ are incompatible with the following options:
  * --exec
  * --no-keep-empty
  * --empty=
- * --reapply-cherry-picks
+ * --[no-]reapply-cherry-picks when used without --keep-base
  * --edit-todo
  * --update-refs
  * --root when used without --onto

diff --git a/builtin/rebase.c b/builtin/rebase.c
index b742cc8fb5c1d600e3ff33982dff577eedecd9c1..05b130bfae5a28b1d36982679f73a29767d0bf00 100644 (file)
--- a/builtin/rebase.c
+++ b/builtin/rebase.c
@@ -1224,13 +1224,6 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
                if (options.fork_point < 0)
                        options.fork_point = 0;
        }
-       /*
-        * --keep-base defaults to --reapply-cherry-picks to avoid losing
-        * commits when using this option.
-        */
-       if (options.reapply_cherry_picks < 0)
-               options.reapply_cherry_picks = keep_base;
-
        if (options.root && options.fork_point > 0)
                die(_("options '%s' and '%s' cannot be used together"), "--root", "--fork-point");
 
@@ -1406,12 +1399,27 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
        if (options.empty != EMPTY_UNSPECIFIED)
                imply_merge(&options, "--empty");
 
-       /*
-        * --keep-base implements --reapply-cherry-picks by altering upstream so
-        * it works with both backends.
-        */
-       if (options.reapply_cherry_picks && !keep_base)
-               imply_merge(&options, "--reapply-cherry-picks");
+       if (options.reapply_cherry_picks < 0)
+               /*
+                * We default to --no-reapply-cherry-picks unless
+                * --keep-base is given; when --keep-base is given, we want
+                * to default to --reapply-cherry-picks.
+                */
+               options.reapply_cherry_picks = keep_base;
+       else if (!keep_base)
+               /*
+                * The apply backend always searches for and drops cherry
+                * picks.  This is often not wanted with --keep-base, so
+                * --keep-base allows --reapply-cherry-picks to be
+                * simulated by altering the upstream such that
+                * cherry-picks cannot be detected and thus all commits are
+                * reapplied.  Thus, --[no-]reapply-cherry-picks is
+                * supported when --keep-base is specified, but not when
+                * --keep-base is left out.
+                */
+               imply_merge(&options, options.reapply_cherry_picks ?
+                                         "--reapply-cherry-picks" :
+                                         "--no-reapply-cherry-picks");
 
        if (gpg_sign)
                options.gpg_sign_opt = xstrfmt("-S%s", gpg_sign);

diff --git a/t/t3422-rebase-incompatible-options.sh b/t/t3422-rebase-incompatible-options.sh
index f86274990b0ad11062a1fc0eb3c865d8090f48fa..826f3b94ae63d0780712db4623fe428a617442b7 100755 (executable)
--- a/t/t3422-rebase-incompatible-options.sh
+++ b/t/t3422-rebase-incompatible-options.sh
@@ -60,6 +60,16 @@ test_rebase_am_only () {
                test_must_fail git rebase $opt --exec 'true' A
        "
 
+       test_expect_success "$opt incompatible with --no-reapply-cherry-picks" "
+               git checkout B^0 &&
+               test_must_fail git rebase $opt --no-reapply-cherry-picks A
+       "
+
+       test_expect_success "$opt incompatible with --reapply-cherry-picks" "
+               git checkout B^0 &&
+               test_must_fail git rebase $opt --reapply-cherry-picks A
+       "
+
        test_expect_success "$opt incompatible with --update-refs" "
                git checkout B^0 &&
                test_must_fail git rebase $opt --update-refs A