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>

3 files changed, 11 insertions, 7 deletions

diff --git a/builtin/checkout.c b/builtin/checkout.c
index 28cdc51..a5717f1 100644
--- a/builtin/checkout.c
+++ b/builtin/checkout.c
@@ -201,7 +201,7 @@ static int checkout_merged(int pos, struct checkout *state)
 }
 
 static int checkout_paths(struct tree *source_tree, const char **pathspec,
-			  struct checkout_opts *opts)
+			  const char *prefix, struct checkout_opts *opts)
 {
 	int pos;
 	struct checkout state;
@@ -231,7 +231,7 @@ static int checkout_paths(struct tree *source_tree, const char **pathspec,
 		match_pathspec(pathspec, ce->name, ce_namelen(ce), 0, ps_matched);
 	}
 
-	if (report_path_error(ps_matched, pathspec, 0))
+	if (report_path_error(ps_matched, pathspec, prefix))
 		return 1;
 
 	/* "checkout -m path" to recreate conflicted state */
@@ -1060,7 +1060,7 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
 		if (1 < !!opts.writeout_stage + !!opts.force + !!opts.merge)
 			die(_("git checkout: --ours/--theirs, --force and --merge are incompatible when\nchecking out of the index."));
 
-		return checkout_paths(source_tree, pathspec, &opts);
+		return checkout_paths(source_tree, pathspec, prefix, &opts);
 	}
 
 	if (patch_mode)
diff --git a/builtin/commit.c b/builtin/commit.c
index e1af9b1..9679a99 100644
--- a/builtin/commit.c
+++ b/builtin/commit.c
@@ -272,7 +272,7 @@ static int list_paths(struct string_list *list, const char *with_tree,
 			item->util = item; /* better a valid pointer than a fake one */
 	}
 
-	return report_path_error(m, pattern, prefix ? strlen(prefix) : 0);
+	return report_path_error(m, pattern, prefix);
 }
 
 static void add_remove_files(struct string_list *list)
diff --git a/builtin/ls-files.c b/builtin/ls-files.c
index 1570123..468bb13 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");