]> git.ipfire.org Git - thirdparty/git.git/commitdiff
replay: add --advance or 'cherry-pick' mode
authorElijah Newren <newren@gmail.com>
Fri, 24 Nov 2023 11:10:41 +0000 (12:10 +0100)
committerJunio C Hamano <gitster@pobox.com>
Sun, 26 Nov 2023 01:10:49 +0000 (10:10 +0900)
There is already a 'rebase' mode with `--onto`. Let's add an 'advance' or
'cherry-pick' mode with `--advance`. This new mode will make the target
branch advance as we replay commits onto it.

The replayed commits should have a single tip, so that it's clear where
the target branch should be advanced. If they have more than one tip,
this new mode will error out.

Co-authored-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Documentation/git-replay.txt
builtin/replay.c
t/t3650-replay-basics.sh

index f7b232caa283482930225544d6b448d9dba61c8c..c4c64f955a0357e7a6f877696f8e574186526bad 100644 (file)
@@ -9,7 +9,7 @@ git-replay - EXPERIMENTAL: Replay commits on a new base, works with bare repos t
 SYNOPSIS
 --------
 [verse]
-(EXPERIMENTAL!) 'git replay' --onto <newbase> <revision-range>...
+(EXPERIMENTAL!) 'git replay' (--onto <newbase> | --advance <branch>) <revision-range>...
 
 DESCRIPTION
 -----------
@@ -29,14 +29,25 @@ OPTIONS
        Starting point at which to create the new commits.  May be any
        valid commit, and not just an existing branch name.
 +
-The update-ref command(s) in the output will update the branch(es) in
-the revision range to point at the new commits, similar to the way how
-`git rebase --update-refs` updates multiple branches in the affected
-range.
+When `--onto` is specified, the update-ref command(s) in the output will
+update the branch(es) in the revision range to point at the new
+commits, similar to the way how `git rebase --update-refs` updates
+multiple branches in the affected range.
+
+--advance <branch>::
+       Starting point at which to create the new commits; must be a
+       branch name.
++
+When `--advance` is specified, the update-ref command(s) in the output
+will update the branch passed as an argument to `--advance` to point at
+the new commits (in other words, this mimics a cherry-pick operation).
 
 <revision-range>::
-       Range of commits to replay; see "Specifying Ranges" in
-       linkgit:git-rev-parse and the "Commit Limiting" options below.
+       Range of commits to replay. More than one <revision-range> can
+       be passed, but in `--advance <branch>` mode, they should have
+       a single tip, so that it's clear where <branch> should point
+       to. See "Specifying Ranges" in linkgit:git-rev-parse and the
+       "Commit Limiting" options below.
 
 include::rev-list-options.txt[]
 
@@ -51,7 +62,9 @@ input to `git update-ref --stdin`.  It is of the form:
        update refs/heads/branch3 ${NEW_branch3_HASH} ${OLD_branch3_HASH}
 
 where the number of refs updated depends on the arguments passed and
-the shape of the history being replayed.
+the shape of the history being replayed.  When using `--advance`, the
+number of refs updated is always one, but for `--onto`, it can be one
+or more (rebasing multiple branches simultaneously is supported).
 
 EXIT STATUS
 -----------
@@ -71,6 +84,18 @@ $ git replay --onto target origin/main..mybranch
 update refs/heads/mybranch ${NEW_mybranch_HASH} ${OLD_mybranch_HASH}
 ------------
 
+To cherry-pick the commits from mybranch onto target:
+
+------------
+$ git replay --advance target origin/main..mybranch
+update refs/heads/target ${NEW_target_HASH} ${OLD_target_HASH}
+------------
+
+Note that the first two examples replay the exact same commits and on
+top of the exact same new base, they only differ in that the first
+provides instructions to make mybranch point at the new commits and
+the second provides instructions to make target point at them.
+
 When calling `git replay`, one does not need to specify a range of
 commits to replay using the syntax `A..B`; any range expression will
 do:
index 3d5e00147bfa834ae829e1fa522888b3252daf3c..f26806d7e2d1cf4df270809f48cf3cec2dc4a397 100644 (file)
@@ -14,6 +14,7 @@
 #include "parse-options.h"
 #include "refs.h"
 #include "revision.h"
+#include "strmap.h"
 #include <oidset.h>
 #include <tree.h>
 
@@ -82,6 +83,146 @@ static struct commit *create_commit(struct tree *tree,
        return (struct commit *)obj;
 }
 
+struct ref_info {
+       struct commit *onto;
+       struct strset positive_refs;
+       struct strset negative_refs;
+       int positive_refexprs;
+       int negative_refexprs;
+};
+
+static void get_ref_information(struct rev_cmdline_info *cmd_info,
+                               struct ref_info *ref_info)
+{
+       int i;
+
+       ref_info->onto = NULL;
+       strset_init(&ref_info->positive_refs);
+       strset_init(&ref_info->negative_refs);
+       ref_info->positive_refexprs = 0;
+       ref_info->negative_refexprs = 0;
+
+       /*
+        * When the user specifies e.g.
+        *   git replay origin/main..mybranch
+        *   git replay ^origin/next mybranch1 mybranch2
+        * we want to be able to determine where to replay the commits.  In
+        * these examples, the branches are probably based on an old version
+        * of either origin/main or origin/next, so we want to replay on the
+        * newest version of that branch.  In contrast we would want to error
+        * out if they ran
+        *   git replay ^origin/master ^origin/next mybranch
+        *   git replay mybranch~2..mybranch
+        * the first of those because there's no unique base to choose, and
+        * the second because they'd likely just be replaying commits on top
+        * of the same commit and not making any difference.
+        */
+       for (i = 0; i < cmd_info->nr; i++) {
+               struct rev_cmdline_entry *e = cmd_info->rev + i;
+               struct object_id oid;
+               const char *refexpr = e->name;
+               char *fullname = NULL;
+               int can_uniquely_dwim = 1;
+
+               if (*refexpr == '^')
+                       refexpr++;
+               if (repo_dwim_ref(the_repository, refexpr, strlen(refexpr), &oid, &fullname, 0) != 1)
+                       can_uniquely_dwim = 0;
+
+               if (e->flags & BOTTOM) {
+                       if (can_uniquely_dwim)
+                               strset_add(&ref_info->negative_refs, fullname);
+                       if (!ref_info->negative_refexprs)
+                               ref_info->onto = lookup_commit_reference_gently(the_repository,
+                                                                               &e->item->oid, 1);
+                       ref_info->negative_refexprs++;
+               } else {
+                       if (can_uniquely_dwim)
+                               strset_add(&ref_info->positive_refs, fullname);
+                       ref_info->positive_refexprs++;
+               }
+
+               free(fullname);
+       }
+}
+
+static void determine_replay_mode(struct rev_cmdline_info *cmd_info,
+                                 const char *onto_name,
+                                 const char **advance_name,
+                                 struct commit **onto,
+                                 struct strset **update_refs)
+{
+       struct ref_info rinfo;
+
+       get_ref_information(cmd_info, &rinfo);
+       if (!rinfo.positive_refexprs)
+               die(_("need some commits to replay"));
+       if (onto_name && *advance_name)
+               die(_("--onto and --advance are incompatible"));
+       else if (onto_name) {
+               *onto = peel_committish(onto_name);
+               if (rinfo.positive_refexprs <
+                   strset_get_size(&rinfo.positive_refs))
+                       die(_("all positive revisions given must be references"));
+       } else if (*advance_name) {
+               struct object_id oid;
+               char *fullname = NULL;
+
+               *onto = peel_committish(*advance_name);
+               if (repo_dwim_ref(the_repository, *advance_name, strlen(*advance_name),
+                            &oid, &fullname, 0) == 1) {
+                       *advance_name = fullname;
+               } else {
+                       die(_("argument to --advance must be a reference"));
+               }
+               if (rinfo.positive_refexprs > 1)
+                       die(_("cannot advance target with multiple sources because ordering would be ill-defined"));
+       } else {
+               int positive_refs_complete = (
+                       rinfo.positive_refexprs ==
+                       strset_get_size(&rinfo.positive_refs));
+               int negative_refs_complete = (
+                       rinfo.negative_refexprs ==
+                       strset_get_size(&rinfo.negative_refs));
+               /*
+                * We need either positive_refs_complete or
+                * negative_refs_complete, but not both.
+                */
+               if (rinfo.negative_refexprs > 0 &&
+                   positive_refs_complete == negative_refs_complete)
+                       die(_("cannot implicitly determine whether this is an --advance or --onto operation"));
+               if (negative_refs_complete) {
+                       struct hashmap_iter iter;
+                       struct strmap_entry *entry;
+
+                       if (rinfo.negative_refexprs == 0)
+                               die(_("all positive revisions given must be references"));
+                       else if (rinfo.negative_refexprs > 1)
+                               die(_("cannot implicitly determine whether this is an --advance or --onto operation"));
+                       else if (rinfo.positive_refexprs > 1)
+                               die(_("cannot advance target with multiple source branches because ordering would be ill-defined"));
+
+                       /* Only one entry, but we have to loop to get it */
+                       strset_for_each_entry(&rinfo.negative_refs,
+                                             &iter, entry) {
+                               *advance_name = entry->key;
+                       }
+               } else { /* positive_refs_complete */
+                       if (rinfo.negative_refexprs > 1)
+                               die(_("cannot implicitly determine correct base for --onto"));
+                       if (rinfo.negative_refexprs == 1)
+                               *onto = rinfo.onto;
+               }
+       }
+       if (!*advance_name) {
+               *update_refs = xcalloc(1, sizeof(**update_refs));
+               **update_refs = rinfo.positive_refs;
+               memset(&rinfo.positive_refs, 0, sizeof(**update_refs));
+       }
+       strset_clear(&rinfo.negative_refs);
+       strset_clear(&rinfo.positive_refs);
+}
+
 static struct commit *pick_regular_commit(struct commit *pickme,
                                          struct commit *last_commit,
                                          struct merge_options *merge_opt,
@@ -114,20 +255,26 @@ static struct commit *pick_regular_commit(struct commit *pickme,
 
 int cmd_replay(int argc, const char **argv, const char *prefix)
 {
-       struct commit *onto;
+       const char *advance_name = NULL;
+       struct commit *onto = NULL;
        const char *onto_name = NULL;
-       struct commit *last_commit = NULL;
+
        struct rev_info revs;
+       struct commit *last_commit = NULL;
        struct commit *commit;
        struct merge_options merge_opt;
        struct merge_result result;
+       struct strset *update_refs = NULL;
        int ret = 0;
 
        const char * const replay_usage[] = {
-               N_("(EXPERIMENTAL!) git replay --onto <newbase> <revision-range>..."),
+               N_("(EXPERIMENTAL!) git replay (--onto <newbase> | --advance <branch>) <revision-range>..."),
                NULL
        };
        struct option replay_options[] = {
+               OPT_STRING(0, "advance", &advance_name,
+                          N_("branch"),
+                          N_("make replay advance given branch")),
                OPT_STRING(0, "onto", &onto_name,
                           N_("revision"),
                           N_("replay onto given commit")),
@@ -137,13 +284,11 @@ int cmd_replay(int argc, const char **argv, const char *prefix)
        argc = parse_options(argc, argv, prefix, replay_options, replay_usage,
                             PARSE_OPT_KEEP_ARGV0 | PARSE_OPT_KEEP_UNKNOWN_OPT);
 
-       if (!onto_name) {
-               error(_("option --onto is mandatory"));
+       if (!onto_name && !advance_name) {
+               error(_("option --onto or --advance is mandatory"));
                usage_with_options(replay_usage, replay_options);
        }
 
-       onto = peel_committish(onto_name);
-
        repo_init_revisions(the_repository, &revs, prefix);
 
        /*
@@ -195,6 +340,12 @@ int cmd_replay(int argc, const char **argv, const char *prefix)
                revs.simplify_history = 0;
        }
 
+       determine_replay_mode(&revs.cmdline, onto_name, &advance_name,
+                             &onto, &update_refs);
+
+       if (!onto) /* FIXME: Should handle replaying down to root commit */
+               die("Replaying down to root commit is not supported yet!");
+
        if (prepare_revision_walk(&revs) < 0) {
                ret = error(_("error preparing revisions"));
                goto cleanup;
@@ -203,6 +354,7 @@ int cmd_replay(int argc, const char **argv, const char *prefix)
        init_merge_options(&merge_opt, the_repository);
        memset(&result, 0, sizeof(result));
        merge_opt.show_rename_progress = 0;
+
        result.tree = repo_get_commit_tree(the_repository, onto);
        last_commit = onto;
        while ((commit = get_revision(&revs))) {
@@ -217,12 +369,15 @@ int cmd_replay(int argc, const char **argv, const char *prefix)
                if (!last_commit)
                        break;
 
+               /* Update any necessary branches */
+               if (advance_name)
+                       continue;
                decoration = get_name_decoration(&commit->object);
                if (!decoration)
                        continue;
-
                while (decoration) {
-                       if (decoration->type == DECORATION_REF_LOCAL) {
+                       if (decoration->type == DECORATION_REF_LOCAL &&
+                           strset_contains(update_refs, decoration->name)) {
                                printf("update %s %s %s\n",
                                       decoration->name,
                                       oid_to_hex(&last_commit->object.oid),
@@ -232,10 +387,22 @@ int cmd_replay(int argc, const char **argv, const char *prefix)
                }
        }
 
+       /* In --advance mode, advance the target ref */
+       if (result.clean == 1 && advance_name) {
+               printf("update %s %s %s\n",
+                      advance_name,
+                      oid_to_hex(&last_commit->object.oid),
+                      oid_to_hex(&onto->object.oid));
+       }
+
        merge_finalize(&merge_opt, &result);
        ret = result.clean;
 
 cleanup:
+       if (update_refs) {
+               strset_clear(update_refs);
+               free(update_refs);
+       }
        release_revisions(&revs);
 
        /* Return */
index a1da4f9ef9afeb17dfef5a7bcc101aa7ac2e32ac..68a87e780375991025262b253014c7d9906175ab 100755 (executable)
@@ -80,4 +80,38 @@ test_expect_success 'using replay on bare repo to rebase with a conflict' '
        test_expect_code 1 git -C bare replay --onto topic1 B..conflict
 '
 
+test_expect_success 'using replay to perform basic cherry-pick' '
+       # The differences between this test and previous ones are:
+       #   --advance vs --onto
+       # 2nd field of result is refs/heads/main vs. refs/heads/topic2
+       # 4th field of result is hash for main instead of hash for topic2
+
+       git replay --advance main topic1..topic2 >result &&
+
+       test_line_count = 1 result &&
+
+       git log --format=%s $(cut -f 3 -d " " result) >actual &&
+       test_write_lines E D M L B A >expect &&
+       test_cmp expect actual &&
+
+       printf "update refs/heads/main " >expect &&
+       printf "%s " $(cut -f 3 -d " " result) >>expect &&
+       git rev-parse main >>expect &&
+
+       test_cmp expect result
+'
+
+test_expect_success 'using replay on bare repo to perform basic cherry-pick' '
+       git -C bare replay --advance main topic1..topic2 >result-bare &&
+       test_cmp expect result-bare
+'
+
+test_expect_success 'replay on bare repo fails with both --advance and --onto' '
+       test_must_fail git -C bare replay --advance main --onto main topic1..topic2 >result-bare
+'
+
+test_expect_success 'replay fails when both --advance and --onto are omitted' '
+       test_must_fail git replay topic1..topic2 >result
+'
+
 test_done