[PATCH v3 1/1] builtin rebase: prepare for builtin rebase -i

["Johannes Schindelin via GitGitGadget" <gitgitgadget@gmail.com>]

From: Johannes Schindelin <johannes.schindelin@gmx.de>

The builtin rebase and the builtin interactive rebase have been
developed independently, on purpose: Google Summer of Code rules
specifically state that students have to work on independent projects,
they cannot collaborate on the same project.

One fallout is that the rebase-in-c and rebase-i-in-c patches cause no
merge conflicts but a royal number of tests in the test suite to fail.

It is easy to explain why: rebase-in-c was developed under the
assumption that all rebase backends are implemented in Unix shell script
and can be sourced via `. git-rebase--<backend>`, which is no longer
true with rebase-i-in-c, where git-rebase--interactive is a hard-linked
builtin.

This patch fixes that.

Please note that we also skip the finish_rebase() call for interactive
rebases because the built-in interactive rebase already takes care of
that. This is needed to support the upcoming `break` command that wants
to interrupt the rebase with exit code 0 (and naturally wants to keep
the state directory intact when doing so).

While at it, remove the `case` arm for the interactive rebase that is
now skipped in favor of the short-cut to the built-in rebase.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
---
 builtin/rebase.c | 87 +++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 83 insertions(+), 4 deletions(-)

diff --git a/builtin/rebase.c b/builtin/rebase.c
index 1a697d70c9..20f7159cf2 100644
--- a/builtin/rebase.c
+++ b/builtin/rebase.c
@@ -326,6 +326,13 @@ static void add_var(struct strbuf *buf, const char *name, const char *value)
 	}
 }
 
+static const char *resolvemsg =
+N_("Resolve all conflicts manually, mark them as resolved with\n"
+"\"git add/rm <conflicted_files>\", then run \"git rebase --continue\".\n"
+"You can instead skip this commit: run \"git rebase --skip\".\n"
+"To abort and get back to the state before \"git rebase\", run "
+"\"git rebase --abort\".");
+
 static int run_specific_rebase(struct rebase_options *opts)
 {
 	const char *argv[] = { NULL, NULL };
@@ -333,6 +340,79 @@ static int run_specific_rebase(struct rebase_options *opts)
 	int status;
 	const char *backend, *backend_func;
 
+	if (opts->type == REBASE_INTERACTIVE) {
+		/* Run builtin interactive rebase */
+		struct child_process child = CHILD_PROCESS_INIT;
+
+		argv_array_pushf(&child.env_array, "GIT_CHERRY_PICK_HELP=%s",
+				 resolvemsg);
+		if (!(opts->flags & REBASE_INTERACTIVE_EXPLICIT)) {
+			argv_array_push(&child.env_array, "GIT_EDITOR=:");
+			opts->autosquash = 0;
+		}
+
+		child.git_cmd = 1;
+		argv_array_push(&child.args, "rebase--interactive");
+
+		if (opts->action)
+			argv_array_pushf(&child.args, "--%s", opts->action);
+		if (opts->keep_empty)
+			argv_array_push(&child.args, "--keep-empty");
+		if (opts->rebase_merges)
+			argv_array_push(&child.args, "--rebase-merges");
+		if (opts->rebase_cousins)
+			argv_array_push(&child.args, "--rebase-cousins");
+		if (opts->autosquash)
+			argv_array_push(&child.args, "--autosquash");
+		if (opts->flags & REBASE_VERBOSE)
+			argv_array_push(&child.args, "--verbose");
+		if (opts->flags & REBASE_FORCE)
+			argv_array_push(&child.args, "--no-ff");
+		if (opts->restrict_revision)
+			argv_array_pushf(&child.args,
+					 "--restrict-revision=^%s",
+					 oid_to_hex(&opts->restrict_revision->object.oid));
+		if (opts->upstream)
+			argv_array_pushf(&child.args, "--upstream=%s",
+					 oid_to_hex(&opts->upstream->object.oid));
+		if (opts->onto)
+			argv_array_pushf(&child.args, "--onto=%s",
+					 oid_to_hex(&opts->onto->object.oid));
+		if (opts->squash_onto)
+			argv_array_pushf(&child.args, "--squash-onto=%s",
+					 oid_to_hex(opts->squash_onto));
+		if (opts->onto_name)
+			argv_array_pushf(&child.args, "--onto-name=%s",
+					 opts->onto_name);
+		argv_array_pushf(&child.args, "--head-name=%s",
+				 opts->head_name ?
+				 opts->head_name : "detached HEAD");
+		if (opts->strategy)
+			argv_array_pushf(&child.args, "--strategy=%s",
+					 opts->strategy);
+		if (opts->strategy_opts)
+			argv_array_pushf(&child.args, "--strategy-opts=%s",
+					 opts->strategy_opts);
+		if (opts->switch_to)
+			argv_array_pushf(&child.args, "--switch-to=%s",
+					 opts->switch_to);
+		if (opts->cmd)
+			argv_array_pushf(&child.args, "--cmd=%s", opts->cmd);
+		if (opts->allow_empty_message)
+			argv_array_push(&child.args, "--allow-empty-message");
+		if (opts->allow_rerere_autoupdate > 0)
+			argv_array_push(&child.args, "--rerere-autoupdate");
+		else if (opts->allow_rerere_autoupdate == 0)
+			argv_array_push(&child.args, "--no-rerere-autoupdate");
+		if (opts->gpg_sign_opt)
+			argv_array_push(&child.args, opts->gpg_sign_opt);
+		if (opts->signoff)
+			argv_array_push(&child.args, "--signoff");
+
+		status = run_command(&child);
+		goto finished_rebase;
+	}
+
 	add_var(&script_snippet, "GIT_DIR", absolute_path(get_git_dir()));
 	add_var(&script_snippet, "state_dir", opts->state_dir);
 
@@ -395,10 +475,6 @@ static int run_specific_rebase(struct rebase_options *opts)
 		backend = "git-rebase--am";
 		backend_func = "git_rebase__am";
 		break;
-	case REBASE_INTERACTIVE:
-		backend = "git-rebase--interactive";
-		backend_func = "git_rebase__interactive";
-		break;
 	case REBASE_MERGE:
 		backend = "git-rebase--merge";
 		backend_func = "git_rebase__merge";
@@ -418,8 +494,11 @@ static int run_specific_rebase(struct rebase_options *opts)
 	argv[0] = script_snippet.buf;
 
 	status = run_command_v_opt(argv, RUN_USING_SHELL);
+finished_rebase:
 	if (opts->dont_finish_rebase)
 		; /* do nothing */
+	else if (opts->type == REBASE_INTERACTIVE)
+		; /* interactive rebase cleans up after itself */
 	else if (status == 0) {
 		if (!file_exists(state_dir_path("stopped-sha", opts)))
 			finish_rebase(opts);
-- 
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