perf: add test for writing the index

diff --git a/vcs-svn/sliding_window.c b/vcs-svn/sliding_window.c
index f11d490995ee7e3367c1d18e1058f2e322cfa177..06d273c9e8ce2b6b8ddbf967693e5305355d5be6 100644 (file)
--- a/vcs-svn/sliding_window.c
+++ b/vcs-svn/sliding_window.c
@@ -12,7 +12,7 @@ static int input_error(struct line_buffer *file)
 {
        if (!buffer_ferror(file))
                return error("delta preimage ends early");
-       return error("cannot read delta preimage: %s", strerror(errno));
+       return error_errno("cannot read delta preimage");
 }
 
 static int skip_or_whine(struct line_buffer *file, off_t gap)