git/list[1] front-page[2] threads[3] people[4] search[5] about
 

[PATCH v2] Require 0 context lines in git-blame algorithm

From
David Kastrup <dak@gnu.org>
Date
May 28, 2016, 09:13 UTC
Message-ID
<1464426833-30406-1-git-send-email-dak@gnu.org>

Previously, the core part of git blame -M required 1 context line. There is no rationale to be found in the code (one guess would be that the old blame algorithm was unable to deal with immediately adjacent regions), and it causes artifacts like discussed in the thread <http://thread.gmane.org/gmane.comp.version-control.git/255289/>.

<http://permalink.gmane.org/gmane.comp.version-control.git/295795> sheds some more light on the history of the previous choice.

Signed-off-by: David Kastrup <dak@gnu.org>
---
 builtin/blame.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)
diff --git a/builtin/blame.c b/builtin/blame.c
index 21f42b0..a3f6874 100644
--- a/builtin/blame.c
+++ b/builtin/blame.c
@@ -134,7 +134,7 @@ struct progress_info {
 	int blamed_lines;
 };
 
-static int diff_hunks(mmfile_t *file_a, mmfile_t *file_b, long ctxlen,
+static int diff_hunks(mmfile_t *file_a, mmfile_t *file_b,
 		      xdl_emit_hunk_consume_func_t hunk_func, void *cb_data)
 {
 	xpparam_t xpp = {0};
@@ -142,7 +142,6 @@ static int diff_hunks(mmfile_t *file_a, mmfile_t *file_b, long ctxlen,
 	xdemitcb_t ecb = {NULL};
 
 	xpp.flags = xdl_opts;
-	xecfg.ctxlen = ctxlen;
 	xecfg.hunk_func = hunk_func;
 	ecb.priv = cb_data;
 	return xdi_diff(file_a, file_b, &xpp, &xecfg, &ecb);
@@ -980,7 +979,7 @@ static void pass_blame_to_parent(struct scoreboard *sb,
 	fill_origin_blob(&sb->revs->diffopt, target, &file_o);
 	num_get_patch++;
 
-	if (diff_hunks(&file_p, &file_o, 0, blame_chunk_cb, &d))
+	if (diff_hunks(&file_p, &file_o, blame_chunk_cb, &d))
 		die("unable to generate diff (%s -> %s)",
 		    oid_to_hex(&parent->commit->object.oid),
 		    oid_to_hex(&target->commit->object.oid));
@@ -1129,7 +1128,7 @@ static void find_copy_in_blob(struct scoreboard *sb,
 	 * file_p partially may match that image.
 	 */
 	memset(split, 0, sizeof(struct blame_entry [3]));
-	if (diff_hunks(file_p, &file_o, 1, handle_split_cb, &d))
+	if (diff_hunks(file_p, &file_o, handle_split_cb, &d))
 		die("unable to generate diff (%s)",
 		    oid_to_hex(&parent->commit->object.oid));
 	/* remainder, if any, all match the preimage */
-- 
2.7.4
Message 1 of 1 in “Require 0 context lines in git-blame algorithm”
  1. Require 0 context lines in git-blame algorithmDavid Kastrup, May 28, 2016

Read the whole thread, see it on lore, or plain text.

$ cat FOOTERMessages come from the public archive at lore.kernel.org/git, fetched every hour. The front page is chosen and written each morning by an AI editor and can be wrong; the threads themselves are the record. About and API. For agents: an MCP server at https://gitlist.dev/mcp, and any thread, story or person page as Markdown by adding .md to its URL (or sending Accept: text/markdown). Details in /llms.txt.