From 8c02407bef55baaee8d721a7e5f7f0ba8d91dd47 Mon Sep 17 00:00:00 2001
From: Viktor Szakats <commit@vsz.me>
Date: Wed, 31 Dec 2025 11:21:18 +0100
Subject: [PATCH] tool_doswin: add debug envs to test filename sanitization
 failure modes

- `CURL_FN_SANITIZE_BAD=<any-value>` to simulate
  `SANITIZE_ERR_INVALID_PATH`.

- `CURL_FN_SANITIZE_OOM=<any-value>` to simulate
  `SANITIZE_ERR_OUT_OF_MEMORY`.

Both are Windows/MS-DOS-specific and require debug-enabled curl build.

Cherry-picked from #20116
Closes #20125
---
 src/tool_doswin.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/src/tool_doswin.c b/src/tool_doswin.c
index 034462b384..a2d6bb81d7 100644
--- a/src/tool_doswin.c
+++ b/src/tool_doswin.c
@@ -206,6 +206,13 @@ SANITIZEcode sanitize_file_name(char ** const sanitized, const char *file_name,
     }
   }
 
+#ifdef DEBUGBUILD
+  if(getenv("CURL_FN_SANITIZE_BAD"))
+    return SANITIZE_ERR_INVALID_PATH;
+  if(getenv("CURL_FN_SANITIZE_OOM"))
+    return SANITIZE_ERR_OUT_OF_MEMORY;
+#endif
+
   *sanitized = target;
   return SANITIZE_ERR_OK;
 }