From 8d662734b6a34709d9475b120e7ce3de872339e2 Mon Sep 17 00:00:00 2001
From: Matthew Fernandez <matthew.fernandez@gmail.com>
Date: Sun, 4 Sep 2022 11:44:01 -0700
Subject: [PATCH] Revert "gvc auto_output_filename: avoid 'strdup' when
 constructing file name"

This reverts commit 4291cc769a3eeef8b1c171e5479194733a4da6cd. This commit that
was intended to be a functional no-op actually altered the generated output
filename to remove `.` characters.

Github: xflr6/graphviz #178, NixOS/nixpkgs #188175
Gitlab: fixes #2270
Reported-by: Sebastian Bank <sebastian.bank@uni-leipzig.de>
---
 CHANGELOG.md             |  2 ++
 lib/gvc/gvdevice.c       | 26 ++++++++------------------
 tests/test_regression.py |  1 -
 3 files changed, 10 insertions(+), 19 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5ab3b3dfd..218a2f913 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -17,6 +17,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Fixed
 
 - Id attribute is not used in linearGradient. #2258
+- Graphviz 5.0.1 undocumented change of automatically generated output filename
+  with -O flag (missing dot separator). This was a regression in 5.0.1. #2270
 
 ### Removed
 
diff --git a/lib/gvc/gvdevice.c b/lib/gvc/gvdevice.c
index aca908f11..dfe68871d 100644
--- a/lib/gvc/gvdevice.c
+++ b/lib/gvc/gvdevice.c
@@ -17,7 +17,6 @@
 #include <ctype.h>
 #include <stdarg.h>
 #include <stdbool.h>
-#include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <inttypes.h>
@@ -87,7 +86,7 @@ static void auto_output_filename(GVJ_t *job)
     static char *buf;
     static size_t bufsz;
     char gidx[100];  /* large enough for '.' plus any integer */
-    char *fn;
+    char *fn, *p, *q;
     size_t len;
 
     if (job->graph_index)
@@ -108,23 +107,14 @@ static void auto_output_filename(GVJ_t *job)
     strcpy(buf, fn);
     strcat(buf, gidx);
     strcat(buf, ".");
-
-    {
-        char *dst = buf + strlen(buf);
-        const char *src = job->output_langname;
-        const char *src_end = src + strlen(src);
-        for (const char *q = src_end; ; --q) {
-            if (*q == ':') {
-                sprintf(dst, "%.*s.", (int)(src_end - q - 1), q + 1);
-                dst += (size_t)(src_end - q - 1);
-                src_end = q;
-            }
-            if (q == src) {
-                sprintf(dst, "%.*s", (int)(src_end - src), src);
-                break;
-            }
-        }
+    p = strdup(job->output_langname);
+    while ((q = strrchr(p, ':'))) {
+        strcat(buf, q+1);
+        strcat(buf, ".");
+	*q = '\0';
     }
+    strcat(buf, p);
+    free(p);
 
     job->output_filename = buf;
 }
diff --git a/tests/test_regression.py b/tests/test_regression.py
index e3fcf5944..6316adf24 100644
--- a/tests/test_regression.py
+++ b/tests/test_regression.py
@@ -1952,7 +1952,6 @@ def test_2258():
   for gradient in gradients:
     assert "G2" in gradient.get("id"), "ID was not applied to linear gradients"
 
-@pytest.mark.xfail(strict=True)
 def test_2270(tmp_path: Path):
   """
   `-O` should result in the expected output filename
-- 
2.40.0