git-commit: Refactor creation of log message.

This patch moves the code of run_commit, up to writing the trees, editing
the message and running the commit-msg hook to prepare_log_message.  It also
renames the latter to prepare_to_commit.

This simplifies a little the code for the next patch.

Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin-commit.c

@@ -377,9 +377,17 @@ static int run_hook(const char *index_file, const char *name, ...)
 	return run_command(&hook);
 }
 
+static int is_a_merge(const unsigned char *sha1)
+{
+	struct commit *commit = lookup_commit(sha1);
+	if (!commit || parse_commit(commit))
+		die("could not parse HEAD commit");
+	return !!(commit->parents && commit->parents->next);
+}
+
 static const char sign_off_header[] = "Signed-off-by: ";
 
-static int prepare_log_message(const char *index_file, const char *prefix)
+static int prepare_to_commit(const char *index_file, const char *prefix)
 {
 	struct stat statbuf;
 	int commitable, saved_color_setting;
@@ -387,6 +395,9 @@ static int prepare_log_message(const char *index_file, const char *prefix)
 	char *buffer;
 	FILE *fp;
 
+	if (!no_verify && run_hook(index_file, "pre-commit", NULL))
+		return 0;
+
 	strbuf_init(&sb, 0);
 	if (message.len) {
 		strbuf_addbuf(&sb, &message);
@@ -447,32 +458,7 @@ static int prepare_log_message(const char *index_file, const char *prefix)
 
 	strbuf_release(&sb);
 
-	if (!use_editor) {
-		struct rev_info rev;
-		unsigned char sha1[20];
-		const char *parent = "HEAD";
-
-		fclose(fp);
-
-		if (!active_nr && read_cache() < 0)
-			die("Cannot read index");
-
-		if (amend)
-			parent = "HEAD^1";
-
-		if (get_sha1(parent, sha1))
-			return !!active_nr;
-
-		init_revisions(&rev, "");
-		rev.abbrev = 0;
-		setup_revisions(0, NULL, &rev, parent);
-		DIFF_OPT_SET(&rev.diffopt, QUIET);
-		DIFF_OPT_SET(&rev.diffopt, EXIT_WITH_STATUS);
-		run_diff_index(&rev, 1 /* cached */);
-
-		return !!DIFF_OPT_TST(&rev.diffopt, HAS_CHANGES);
-	}
-
+	if (use_editor) {
 		if (in_merge)
 			fprintf(fp,
 				"#\n"
@@ -499,10 +485,68 @@ static int prepare_log_message(const char *index_file, const char *prefix)
 		wt_status_use_color = 0;
 		commitable = run_status(fp, index_file, prefix, 1);
 		wt_status_use_color = saved_color_setting;
+	} else {
+		struct rev_info rev;
+		unsigned char sha1[20];
+		const char *parent = "HEAD";
+
+		if (!active_nr && read_cache() < 0)
+			die("Cannot read index");
+
+		if (amend)
+			parent = "HEAD^1";
+
+		if (get_sha1(parent, sha1))
+			commitable = !!active_nr;
+		else {
+			init_revisions(&rev, "");
+			rev.abbrev = 0;
+			setup_revisions(0, NULL, &rev, parent);
+			DIFF_OPT_SET(&rev.diffopt, QUIET);
+			DIFF_OPT_SET(&rev.diffopt, EXIT_WITH_STATUS);
+			run_diff_index(&rev, 1 /* cached */);
+
+			commitable = !!DIFF_OPT_TST(&rev.diffopt, HAS_CHANGES);
+		}
+	}
 
 	fclose(fp);
 
-	return commitable;
+	if (!commitable && !in_merge && !allow_empty &&
+	    !(amend && is_a_merge(head_sha1))) {
+		run_status(stdout, index_file, prefix, 0);
+		unlink(commit_editmsg);
+		return 0;
+	}
+
+	/*
+	 * Re-read the index as pre-commit hook could have updated it,
+	 * and write it out as a tree.  We must do this before we invoke
+	 * the editor and after we invoke run_status above.
+	 */
+	discard_cache();
+	read_cache_from(index_file);
+	if (!active_cache_tree)
+		active_cache_tree = cache_tree();
+	if (cache_tree_update(active_cache_tree,
+			      active_cache, active_nr, 0, 0) < 0) {
+		error("Error building trees");
+		return 0;
+	}
+
+	if (use_editor) {
+		char index[PATH_MAX];
+		const char *env[2] = { index, NULL };
+		snprintf(index, sizeof(index), "GIT_INDEX_FILE=%s", index_file);
+		launch_editor(git_path(commit_editmsg), NULL, env);
+	}
+
+	if (!no_verify &&
+	    run_hook(index_file, "commit-msg", git_path(commit_editmsg), NULL)) {
+		return 0;
+	}
+
+	return 1;
 }
 
 /*
@@ -761,14 +805,6 @@ int git_commit_config(const char *k, const char *v)
 	return git_status_config(k, v);
 }
 
-static int is_a_merge(const unsigned char *sha1)
-{
-	struct commit *commit = lookup_commit(sha1);
-	if (!commit || parse_commit(commit))
-		die("could not parse HEAD commit");
-	return !!(commit->parents && commit->parents->next);
-}
-
 static const char commit_utf8_warn[] =
 "Warning: commit message does not conform to UTF-8.\n"
 "You may want to amend it after fixing the message, or set the config\n"
@@ -800,33 +836,13 @@ int cmd_commit(int argc, const char **argv, const char *prefix)
 
 	index_file = prepare_index(argc, argv, prefix);
 
-	if (!no_verify && run_hook(index_file, "pre-commit", NULL)) {
-		rollback_index_files();
-		return 1;
-	}
-
-	if (!prepare_log_message(index_file, prefix) && !in_merge &&
-	    !allow_empty && !(amend && is_a_merge(head_sha1))) {
-		run_status(stdout, index_file, prefix, 0);
+	/* Set up everything for writing the commit object.  This includes
+	   running hooks, writing the trees, and interacting with the user.  */
+	if (!prepare_to_commit(index_file, prefix)) {
 		rollback_index_files();
-		unlink(commit_editmsg);
 		return 1;
 	}
 
-	/*
-	 * Re-read the index as pre-commit hook could have updated it,
-	 * and write it out as a tree.
-	 */
-	discard_cache();
-	read_cache_from(index_file);
-	if (!active_cache_tree)
-		active_cache_tree = cache_tree();
-	if (cache_tree_update(active_cache_tree,
-			      active_cache, active_nr, 0, 0) < 0) {
-		rollback_index_files();
-		die("Error building trees");
-	}
-
 	/*
 	 * The commit object
 	 */
@@ -878,19 +894,8 @@ int cmd_commit(int argc, const char **argv, const char *prefix)
 		strbuf_addf(&sb, "encoding %s\n", git_commit_encoding);
 	strbuf_addch(&sb, '\n');
 
-	/* Get the commit message and validate it */
+	/* Finally, get the commit message */
 	header_len = sb.len;
-	if (use_editor) {
-		char index[PATH_MAX];
-		const char *env[2] = { index, NULL };
-		snprintf(index, sizeof(index), "GIT_INDEX_FILE=%s", index_file);
-		launch_editor(git_path(commit_editmsg), NULL, env);
-	}
-	if (!no_verify &&
-	    run_hook(index_file, "commit-msg", git_path(commit_editmsg), NULL)) {
-		rollback_index_files();
-		exit(1);
-	}
 	if (strbuf_read_file(&sb, git_path(commit_editmsg), 0) < 0) {
 		rollback_index_files();
 		die("could not read commit message");

t/t7502-commit.sh

@@ -154,4 +154,33 @@ test_expect_success 'cleanup commit messages (strip,-F,-e)' '
 
 '
 
+pwd=`pwd`
+cat >> .git/FAKE_EDITOR << EOF
+#! /bin/sh
+echo editor started > "$pwd/.git/result"
+exit 0
+EOF
+chmod +x .git/FAKE_EDITOR
+
+test_expect_success 'do not fire editor in the presence of conflicts' '
+
+	git clean
+	echo f>g
+	git add g
+	git commit -myes
+	git branch second
+	echo master>g
+	echo g>h
+	git add g h
+	git commit -mmaster
+	git checkout second
+	echo second>g
+	git add g
+	git commit -msecond
+	git cherry-pick -n master
+	echo "editor not started" > .git/result
+	GIT_EDITOR=`pwd`/.git/FAKE_EDITOR git commit && exit 1  # should fail
+	test "`cat .git/result`" = "editor not started"
+'
+
 test_done