[PATCH v3 04/13] fast-rebase: write conflict state to working tree, index, and HEAD

From: Elijah Newren via GitGitGadget <gitgitgadget@gmail.com>
Date: May 20, 2021, 06:09 UTC
Message-ID: <cfd8cbef17f03a97b20196bebf7abc04572a79b2.1621490982.git.gitgitgadget@gmail.com>
In-Reply-To: <pull.859.v3.git.1621490982.gitgitgadget@gmail.com>

From: Elijah Newren <newren@gmail.com>

Previously, when fast-rebase hit a conflict, it simply aborted and left HEAD, the index, and the working tree where they were before the operation started. While fast-rebase does not support restarting from a conflicted state, write the conflicted state out anyway as it gives us a way to see what the conflicts are and write tests that check for them.

This will be important in the upcoming commits, because sequencer.c is only superficially integrated with merge-ort.c; in particular, it calls merge_switch_to_result() after EACH merge instead of only calling it at the end of all the sequence of merges (or when a conflict is hit). This not only causes needless updates to the working copy and index, but also causes all intermediate data to be freed and tossed, preventing caching information from one merge to the next. However, integrating sequencer.c more deeply with merge-ort.c is a big task, and making this small extension to fast-rebase.c provides us with a simple way to test the edge and corner cases that we want to make sure continue working.

Signed-off-by: Elijah Newren <newren@gmail.com>
---
 t/helper/test-fast-rebase.c | 51 +++++++++++++++++++++++--------------
 1 file changed, 32 insertions(+), 19 deletions(-)

diff --git a/t/helper/test-fast-rebase.c b/t/helper/test-fast-rebase.c
index 39fb7f41e8c1..fc2d46090434 100644
--- a/t/helper/test-fast-rebase.c
+++ b/t/helper/test-fast-rebase.c
@@ -91,7 +91,6 @@ int cmd__fast_rebase(int argc, const char **argv)
 	struct commit *last_commit = NULL, *last_picked_commit = NULL;
 	struct object_id head;
 	struct lock_file lock = LOCK_INIT;
-	int clean = 1;
 	struct strvec rev_walk_args = STRVEC_INIT;
 	struct rev_info revs;
 	struct commit *commit;
@@ -176,11 +175,10 @@ int cmd__fast_rebase(int argc, const char **argv)
 		free((char*)merge_opt.ancestor);
 		merge_opt.ancestor = NULL;
 		if (!result.clean)
-			die("Aborting: Hit a conflict and restarting is not implemented.");
+			break;
 		last_picked_commit = commit;
 		last_commit = create_commit(result.tree, commit, last_commit);
 	}
-	fprintf(stderr, "\nDone.\n");
 	/* TODO: There should be some kind of rev_info_free(&revs) call... */
 	memset(&revs, 0, sizeof(revs));
 
@@ -189,24 +187,39 @@ int cmd__fast_rebase(int argc, const char **argv)
 	if (result.clean < 0)
 		exit(128);
 
-	strbuf_addf(&reflog_msg, "finish rebase %s onto %s",
-		    oid_to_hex(&last_picked_commit->object.oid),
-		    oid_to_hex(&last_commit->object.oid));
-	if (update_ref(reflog_msg.buf, branch_name.buf,
-		       &last_commit->object.oid,
-		       &last_picked_commit->object.oid,
-		       REF_NO_DEREF, UPDATE_REFS_MSG_ON_ERR)) {
-		error(_("could not update %s"), argv[4]);
-		die("Failed to update %s", argv[4]);
+	if (result.clean) {
+		fprintf(stderr, "\nDone.\n");
+		strbuf_addf(&reflog_msg, "finish rebase %s onto %s",
+			    oid_to_hex(&last_picked_commit->object.oid),
+			    oid_to_hex(&last_commit->object.oid));
+		if (update_ref(reflog_msg.buf, branch_name.buf,
+			       &last_commit->object.oid,
+			       &last_picked_commit->object.oid,
+			       REF_NO_DEREF, UPDATE_REFS_MSG_ON_ERR)) {
+			error(_("could not update %s"), argv[4]);
+			die("Failed to update %s", argv[4]);
+		}
+		if (create_symref("HEAD", branch_name.buf, reflog_msg.buf) < 0)
+			die(_("unable to update HEAD"));
+		strbuf_release(&reflog_msg);
+		strbuf_release(&branch_name);
+
+		prime_cache_tree(the_repository, the_repository->index,
+				 result.tree);
+	} else {
+		fprintf(stderr, "\nAborting: Hit a conflict.\n");
+		strbuf_addf(&reflog_msg, "rebase progress up to %s",
+			    oid_to_hex(&last_picked_commit->object.oid));
+		if (update_ref(reflog_msg.buf, "HEAD",
+			       &last_commit->object.oid,
+			       &head,
+			       REF_NO_DEREF, UPDATE_REFS_MSG_ON_ERR)) {
+			error(_("could not update %s"), argv[4]);
+			die("Failed to update %s", argv[4]);
+		}
 	}
-	if (create_symref("HEAD", branch_name.buf, reflog_msg.buf) < 0)
-		die(_("unable to update HEAD"));
-	strbuf_release(&reflog_msg);
-	strbuf_release(&branch_name);
-
-	prime_cache_tree(the_repository, the_repository->index, result.tree);
 	if (write_locked_index(&the_index, &lock,
 			       COMMIT_LOCK | SKIP_IF_UNCHANGED))
 		die(_("unable to write %s"), get_index_file());
-	return (clean == 0);
+	return (result.clean == 0);
 }

-- 
gitgitgadget