ls-files: fix pathspec display on error

The following sequence of commands reveals an issue with error
reporting of relative paths:

 $ mkdir sub
 $ cd sub
 $ git ls-files --error-unmatch ../bbbbb
 error: pathspec 'b' did not match any file(s) known to git.
 $ git commit --error-unmatch ../bbbbb
 error: pathspec 'b' did not match any file(s) known to git.

This bug is visible only if the normalized path (i.e., the relative
path from the repository root) is longer than the prefix.
Otherwise, the code skips over the normalized path and reads from
an unused memory location which still contains a leftover of the
original command line argument.

So instead, use the existing facilities to deal with relative paths
correctly.

Also fix inconsistency between "checkout" and "commit", e.g.

    $ cd Documentation
    $ git checkout nosuch.txt
    error: pathspec 'Documentation/nosuch.txt' did not match...
    $ git commit nosuch.txt
    error: pathspec 'nosuch.txt' did not match...

by propagating the prefix down the codepath that reports the error.

Signed-off-by: Clemens Buchacher <drizzd@aon.at>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 7 insertions, 3 deletions

diff --git a/builtin/ls-files.c b/builtin/ls-files.c
index 15701233e..468bb13c8 100644
--- a/builtin/ls-files.c
+++ b/builtin/ls-files.c
@@ -388,11 +388,13 @@ void overlay_tree_on_cache(const char *tree_name, const char *prefix)
 	}
 }
 
-int report_path_error(const char *ps_matched, const char **pathspec, int prefix_len)
+int report_path_error(const char *ps_matched, const char **pathspec, const char *prefix)
 {
 	/*
 	 * Make sure all pathspec matched; otherwise it is an error.
 	 */
+	struct strbuf sb = STRBUF_INIT;
+	const char *name;
 	int num, errors = 0;
 	for (num = 0; pathspec[num]; num++) {
 		int other, found_dup;
@@ -417,10 +419,12 @@ int report_path_error(const char *ps_matched, const char **pathspec, int prefix_
 		if (found_dup)
 			continue;
 
+		name = quote_path_relative(pathspec[num], -1, &sb, prefix);
 		error("pathspec '%s' did not match any file(s) known to git.",
-		      pathspec[num] + prefix_len);
+		      name);
 		errors++;
 	}
+	strbuf_release(&sb);
 	return errors;
 }
 
@@ -611,7 +615,7 @@ int cmd_ls_files(int argc, const char **argv, const char *cmd_prefix)
 
 	if (ps_matched) {
 		int bad;
-		bad = report_path_error(ps_matched, pathspec, prefix_len);
+		bad = report_path_error(ps_matched, pathspec, prefix);
 		if (bad)
 			fprintf(stderr, "Did you forget to 'git add'?\n");