[PATCH 2/4] attr: notice and report read failure of .gitattributes files

From: Junio C Hamano <gitster@pobox.com>
Date: Jun 18, 2024, 23:44 UTC
Message-ID: <20240618234436.4107855-3-gitster@pobox.com>
In-Reply-To: <20240618234436.4107855-1-gitster@pobox.com>

The code that reads .gitattributes files was careless in dealing in unusual circumstances.

 - It let read errors silently ignored.

 - It tried to read ".gitattributes" that is a directory on
   platforms that allowed open(2) to open directories.

To make the latter consistent with what we do for fopen() on directories ("git grep" for FREAD_READS_DIRECTORIES for details), check if we opened a directory, silently close it and return success. Catch all read errors before we close and report as needed.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 attr.c                | 10 +++++++++-
 t/t0003-attributes.sh |  9 +++++++++
 2 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/attr.c b/attr.c
index 300f994ba6..9ab9cf1551 100644
--- a/attr.c
+++ b/attr.c
@@ -747,6 +747,11 @@ static struct attr_stack *read_attr_from_file(const char *path, unsigned flags)
 		fclose(fp);
 		return NULL;
 	}
+	if (S_ISDIR(st.st_mode)) {
+		/* On FREAD_READS_DIRECTORIES platforms */
+		fclose(fp);
+		return NULL;
+	}
 	if (st.st_size >= ATTR_MAX_FILE_SIZE) {
 		warning(_("ignoring overly large gitattributes file '%s'"), path);
 		fclose(fp);
@@ -760,7 +765,10 @@ static struct attr_stack *read_attr_from_file(const char *path, unsigned flags)
 		handle_attr_line(res, buf.buf, path, ++lineno, flags);
 	}
 
-	fclose(fp);
+	if (ferror(fp))
+		warning_errno(_("failed while reading gitattributes file '%s'"), path);
+	if (fclose(fp))
+		warning_errno(_("cannot fclose gitattributes file '%s'"), path);
 	strbuf_release(&buf);
 	return res;
 }
diff --git a/t/t0003-attributes.sh b/t/t0003-attributes.sh
index 66ccb5889d..783c20146d 100755
--- a/t/t0003-attributes.sh
+++ b/t/t0003-attributes.sh
@@ -603,6 +603,15 @@ test_expect_success EXPENSIVE 'large attributes blob ignored' '
 	test_cmp expect err
 '
 
+test_expect_success '.gitattribute directory behaves as if it does not exist' '
+	test_when_finished "rm -fr dir" &&
+	mkdir -p dir/.gitattributes &&
+	>dir/ectory &&
+	git -C dir check-attr --all ectory >out 2>err &&
+	test_grep ! "failed while reading" err &&
+	test_grep ! "cannot fclose" err
+'
+
 test_expect_success 'builtin object mode attributes work (dir and regular paths)' '
 	>normal &&
 	attr_check_object_mode normal 100644 &&

-- 
2.45.2-711-gd2c001ca14