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

[PATCH] blame.c: fix garbled error message

From
LFLukas Fleischer <git@cryptocrack.de>
Date
Jan 10, 2015, 21:33 UTC
Message-ID
<1420925601-21615-1-git-send-email-git@cryptocrack.de>

The helper functions prepare_final() and prepare_initial() return a pointer to a string that is a member of an object in the revs->pending array. This array is later rebuilt when running prepare_revision_walk() which potentially transforms the pointer target into a bogus string. Fix this by maintaining a copy of the original string.

Signed-off-by: Lukas Fleischer <git@cryptocrack.de>
---
The bug manifests when running `git blame HEAD^ -- nonexistent.file`.

Note that I could have reduced code churn a little by moving the xstrdup() invocations to the call sites. However, I think that the return value of these functions should not depend on the consistency of a volatile data structure. On the other hand, you might also argue that there currently are only two call sites and that the functions are marked static, so if you prefer the less intrusive version, please let me know.

 builtin/blame.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)
diff --git a/builtin/blame.c b/builtin/blame.c
index 303e217..34d6f4f 100644
--- a/builtin/blame.c
+++ b/builtin/blame.c
@@ -2390,7 +2390,7 @@ static struct commit *fake_working_tree_commit(struct diff_options *opt,
 	return commit;
 }
 
-static const char *prepare_final(struct scoreboard *sb)
+static char *prepare_final(struct scoreboard *sb)
 {
 	int i;
 	const char *final_commit_name = NULL;
@@ -2415,10 +2415,10 @@ static const char *prepare_final(struct scoreboard *sb)
 		sb->final = (struct commit *) obj;
 		final_commit_name = revs->pending.objects[i].name;
 	}
-	return final_commit_name;
+	return xstrdup(final_commit_name);
 }
 
-static const char *prepare_initial(struct scoreboard *sb)
+static char *prepare_initial(struct scoreboard *sb)
 {
 	int i;
 	const char *final_commit_name = NULL;
@@ -2445,7 +2445,7 @@ static const char *prepare_initial(struct scoreboard *sb)
 	}
 	if (!final_commit_name)
 		die("No commit to dig down to?");
-	return final_commit_name;
+	return xstrdup(final_commit_name);
 }
 
 static int blame_copy_callback(const struct option *option, const char *arg, int unset)
@@ -2489,7 +2489,7 @@ int cmd_blame(int argc, const char **argv, const char *prefix)
 	struct origin *o;
 	struct blame_entry *ent = NULL;
 	long dashdash_pos, lno;
-	const char *final_commit_name = NULL;
+	char *final_commit_name = NULL;
 	enum object_type type;
 
 	static struct string_list range_list;
@@ -2786,6 +2786,8 @@ parse_done:
 
 	assign_blame(&sb, opt);
 
+	free(final_commit_name);
+
 	if (incremental)
 		return 0;
 
-- 
2.2.1
Next: Junio C Hamano
Message 1 of 19 in “blame.c: fix garbled error message”
  1. blame.c: fix garbled error messageLukas Fleischer, Jan 10, 2015
  2. Junio C HamanoJan 12, 2015
  3. Jeff KingJan 12, 2015
  4. Junio C HamanoJan 12, 2015
  5. Jeff KingJan 12, 2015
  6. Junio C HamanoJan 13, 2015
  7. Jeff KingJan 13, 2015
  8. 1/5 git-compat-util: add xstrdup_or_null helperJeff King, Jan 13, 2015
  9. Jonathan NiederJan 13, 2015
  10. Jeff KingJan 13, 2015
  11. 2/5 builtin/apply.c: use xstrdup_or_null instead of null_strdupJeff King, Jan 13, 2015
  12. 3/5 builtin/commit.c: use xstrdup_or_null instead of envdupJeff King, Jan 13, 2015
  13. 4/5 use xstrdup_or_null to replace ternary conditionalsJeff King, Jan 13, 2015
  14. 5/5 blame.c: fix garbled error messageJeff King, Jan 13, 2015
  15. Lukas FleischerJan 14, 2015
  16. Junio C HamanoJan 14, 2015
  17. Jeff KingJan 14, 2015
  18. Junio C HamanoJan 14, 2015
  19. Lukas FleischerJan 12, 2015

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.