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[PATCH 11,13,14 v2] revert: clarify label on conflict hunks

From
Jonathan Nieder <jrnieder@gmail.com>
Date
Mar 18, 2010, 03:33 UTC
Message-ID
<20100318033316.GB18193@progeny.tock>
In-Reply-To
<20100318031638.GA18193@progeny.tock>

When reverting a commit, the commit being merged is not the commit to revert itself but its parent. Clarify the text in conflict hunks to explain this.

Example:
	<<<<<<< HEAD
	Something old.
	Something new.
	Something blue.
	=======
	Something old.
	Something rotten.
	Something blue.
	>>>>>>> parent of ac789a9... Remove rotten line

Also free a temporary buffer that was not freed before. This is not important because it is a small one-time allocation. It would become a memory leak if unnoticed when libifying cherry-pick.

Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
This rearranges the code a little to make it easier to read and
manipulate.
 builtin/revert.c                |  100 ++++++++++++++++++++++++---------------
 t/t3507-cherry-pick-conflict.sh |    4 +-
 2 files changed, 63 insertions(+), 41 deletions(-)
diff --git a/builtin/revert.c b/builtin/revert.c
index eff5268..b314629 100644
--- a/builtin/revert.c
+++ b/builtin/revert.c
@@ -45,6 +45,8 @@ static const char *me;
 
 #define GIT_REFLOG_ACTION "GIT_REFLOG_ACTION"
 
+static char *get_encoding(const char *message);
+
 static void parse_args(int argc, const char **argv)
 {
 	const char * const * usage_str =
@@ -73,33 +75,63 @@ static void parse_args(int argc, const char **argv)
 		exit(1);
 }
 
-static char *get_oneline(const char *message)
+struct commit_message {
+	char *parent_label;
+	const char *label;
+	const char *subject;
+	char *reencoded_message;
+	const char *message;
+};
+
+static int get_message(const char *raw_message, struct commit_message *out)
 {
-	char *result;
-	const char *p = message, *abbrev, *eol;
+	const char *encoding;
+	const char *p, *abbrev, *eol;
+	char *q;
 	int abbrev_len, oneline_len;
 
-	if (!p)
-		die ("Could not read commit message of %s",
-				sha1_to_hex(commit->object.sha1));
+	if (!raw_message)
+		return -1;
+	encoding = get_encoding(raw_message);
+	if (!encoding)
+		encoding = "UTF-8";
+	if (!git_commit_encoding)
+		git_commit_encoding = "UTF-8";
+	if ((out->reencoded_message = reencode_string(raw_message,
+					git_commit_encoding, encoding)))
+		out->message = out->reencoded_message;
+
+	abbrev = find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV);
+	abbrev_len = strlen(abbrev);
+
+	/* Find beginning and end of commit subject. */
+	p = out->message;
 	while (*p && (*p != '\n' || p[1] != '\n'))
 		p++;
-
 	if (*p) {
 		p += 2;
 		for (eol = p + 1; *eol && *eol != '\n'; eol++)
 			; /* do nothing */
 	} else
 		eol = p;
-	abbrev = find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV);
-	abbrev_len = strlen(abbrev);
 	oneline_len = eol - p;
-	result = xmalloc(abbrev_len + 5 + oneline_len);
-	memcpy(result, abbrev, abbrev_len);
-	memcpy(result + abbrev_len, "... ", 4);
-	memcpy(result + abbrev_len + 4, p, oneline_len);
-	result[abbrev_len + 4 + oneline_len] = '\0';
-	return result;
+
+	out->parent_label = xmalloc(strlen("parent of ") + abbrev_len +
+			      strlen("... ") + oneline_len + 1);
+	q = out->parent_label;
+	q = mempcpy(q, "parent of ", strlen("parent of "));
+	out->label = q;
+	q = mempcpy(q, abbrev, abbrev_len);
+	q = mempcpy(q, "... ", strlen("... "));
+	out->subject = q;
+	q = mempcpy(q, p, oneline_len);
+	*q = '\0';
+	return 0;
+}
+
+static void free_message(struct commit_message *msg) {
+	free(msg->parent_label);
+	free(msg->reencoded_message);
 }
 
 static char *get_encoding(const char *message)
@@ -248,9 +280,10 @@ static int revert_or_cherry_pick(int argc, const char **argv)
 {
 	unsigned char head[20];
 	struct commit *base, *next, *parent;
+	const char *next_label;
 	int i, index_fd, clean;
-	char *oneline, *reencoded_message = NULL;
-	const char *message, *encoding;
+	struct commit_message msg = { NULL, NULL, NULL, NULL, NULL };
+
 	char *defmsg = git_pathdup("MERGE_MSG");
 	struct merge_options o;
 	struct tree *result, *next_tree, *base_tree, *head_tree;
@@ -314,14 +347,14 @@ static int revert_or_cherry_pick(int argc, const char **argv)
 	else
 		parent = commit->parents->item;
 
-	if (!(message = commit->buffer))
-		die ("Cannot get commit message for %s",
-				sha1_to_hex(commit->object.sha1));
-
 	if (parent && parse_commit(parent) < 0)
 		die("%s: cannot parse parent commit %s",
 		    me, sha1_to_hex(parent->object.sha1));
 
+	if (get_message(commit->buffer, &msg) != 0)
+		die ("Cannot get commit message for %s",
+				sha1_to_hex(commit->object.sha1));
+
 	/*
 	 * "commit" is an existing commit.  We would want to apply
 	 * the difference it introduces since its first parent "prev"
@@ -332,24 +365,12 @@ static int revert_or_cherry_pick(int argc, const char **argv)
 	msg_fd = hold_lock_file_for_update(&msg_file, defmsg,
 					   LOCK_DIE_ON_ERROR);
 
-	encoding = get_encoding(message);
-	if (!encoding)
-		encoding = "UTF-8";
-	if (!git_commit_encoding)
-		git_commit_encoding = "UTF-8";
-	if ((reencoded_message = reencode_string(message,
-					git_commit_encoding, encoding)))
-		message = reencoded_message;
-
-	oneline = get_oneline(message);
-
 	if (action == REVERT) {
-		char *oneline_body = strchr(oneline, ' ');
-
 		base = commit;
 		next = parent;
+		next_label = msg.parent_label;
 		add_to_msg("Revert \"");
-		add_to_msg(oneline_body + 1);
+		add_to_msg(msg.subject);
 		add_to_msg("\"\n\nThis reverts commit ");
 		add_to_msg(sha1_to_hex(commit->object.sha1));
 
@@ -361,8 +382,9 @@ static int revert_or_cherry_pick(int argc, const char **argv)
 	} else {
 		base = parent;
 		next = commit;
-		set_author_ident_env(message);
-		add_message_to_msg(message);
+		next_label = msg.label;
+		set_author_ident_env(msg.message);
+		add_message_to_msg(msg.message);
 		if (no_replay) {
 			add_to_msg("(cherry picked from commit ");
 			add_to_msg(sha1_to_hex(commit->object.sha1));
@@ -373,7 +395,7 @@ static int revert_or_cherry_pick(int argc, const char **argv)
 	read_cache();
 	init_merge_options(&o);
 	o.branch1 = "HEAD";
-	o.branch2 = oneline;
+	o.branch2 = next ? next_label : "(empty tree)";
 
 	head_tree = parse_tree_indirect(head);
 	next_tree = next ? next->tree : empty_tree();
@@ -437,7 +459,7 @@ static int revert_or_cherry_pick(int argc, const char **argv)
 		args[i] = NULL;
 		return execv_git_cmd(args);
 	}
-	free(reencoded_message);
+	free_message(&msg);
 	free(defmsg);
 
 	return 0;
diff --git a/t/t3507-cherry-pick-conflict.sh b/t/t3507-cherry-pick-conflict.sh
index e856356..6a20817 100644
--- a/t/t3507-cherry-pick-conflict.sh
+++ b/t/t3507-cherry-pick-conflict.sh
@@ -138,7 +138,7 @@ test_expect_success 'revert also handles conflicts sanely' '
 	a
 	=======
 	b
-	>>>>>>> objid picked
+	>>>>>>> parent of objid picked
 	EOF
 	{
 		git checkout picked -- foo &&
@@ -183,7 +183,7 @@ test_expect_success 'revert conflict, diff3 -m style' '
 	c
 	=======
 	b
-	>>>>>>> objid picked
+	>>>>>>> parent of objid picked
 	EOF
 
 	git update-index --refresh &&

-- 
1.7.0
Previous: Jonathan NiederNext: Jonathan Nieder
Message 17 of 23 in “Add label for common ancestor to conflictstyle=diff3”
  1. 0/16 Add label for common ancestor to conflictstyle=diff3Jonathan Nieder, Mar 17, 2010
  2. 01/16 xdl_merge(): add optional ancestor label to diff3-style outputJonathan Nieder, Mar 17, 2010
  3. Bert WesargMar 17, 2010
  4. Jonathan NiederMar 20, 2010
  5. 02/16 xdl_merge(): move file1 and file2 labels to xmparam structureJonathan Nieder, Mar 17, 2010
  6. 03/16 merge-file --diff3: add a label for ancestorJonathan Nieder, Mar 17, 2010
  7. 04/16 ll_merge(): add ancestor label parameter for diff3-style outputJonathan Nieder, Mar 17, 2010
  8. 05/16 checkout --conflict=diff3: add a label for ancestorJonathan Nieder, Mar 17, 2010
  9. 06/16 merge_file(): add comment explaining behavior wrt conflict styleJonathan Nieder, Mar 17, 2010
  10. 07/16 merge_trees(): add ancestor label parameter for diff3-style outputJonathan Nieder, Mar 17, 2010
  11. 08/16 tests: document format of conflicts from checkout -mJonathan Nieder, Mar 17, 2010
  12. 09/16 checkout -m --conflict=diff3: add a label for ancestorJonathan Nieder, Mar 17, 2010
  13. 10/16 tests: document cherry-pick behavior in face of conflictsJonathan Nieder, Mar 17, 2010
  14. 11/16 revert_or_cherry_pick(): get oneline_body from get_oneline()Jonathan Nieder, Mar 17, 2010
  15. Stephen BoydMar 17, 2010
  16. Jonathan NiederMar 18, 2010
  17. revert: clarify label on conflict hunksJonathan Nieder, Mar 18, 2010
  18. 15/16 cherry-pick, revert: add a label for ancestorJonathan Nieder, Mar 18, 2010
  19. 12/16 compat: add mempcpy()Jonathan Nieder, Mar 17, 2010
  20. 13/16 revert: simplify get_oneline() using mempcpyJonathan Nieder, Mar 17, 2010
  21. 14/16 revert: clarify label on conflict hunksJonathan Nieder, Mar 17, 2010
  22. 15/16 cherry-pick: add a label for ancestorJonathan Nieder, Mar 17, 2010
  23. 16/16 merge-recursive: add a label for ancestorJonathan Nieder, Mar 17, 2010

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