From f84598f66a080200f95498e48bd9b36d388f5ee8 Mon Sep 17 00:00:00 2001
From: "Sergio R. Caprile" <scaprile@cesanta.com>
Date: Thu, 9 Jul 2026 10:58:04 -0300
Subject: [PATCH] mdash/mingw does not support %zu

---
 .github/workflows/nightly.yml | 6 +++---
 test/unit_test.c              | 4 ++--
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/.github/workflows/nightly.yml b/.github/workflows/nightly.yml
index a204ed9a..a6110961 100644
--- a/.github/workflows/nightly.yml
+++ b/.github/workflows/nightly.yml
@@ -340,7 +340,7 @@ jobs:
       fail-fast: false
       max-parallel: 1   # no parallel runs, to minimize MQTT errors
       matrix:
-        target: [vc98, vc17, vc22, mingw, mingw++]
+        target: [vc98, vc17, vc22, mingw, mingw++] # current mdash/mingw image compiler does not have support for %zu; test disabled below
         ssl: ["", BUILTIN]
         select: [-DMG_ENABLE_POLL=0, -DMG_ENABLE_POLL=1]
         exclude:
@@ -349,14 +349,14 @@ jobs:
     name: windows ${{ matrix.target }} SSL=${{ matrix.ssl }} TFLAGS=${{ matrix.select }}
     env:
       SSL: ${{ matrix.ssl }}
-      TFLAGS: ${{ matrix.select }} -DMQTT_LOCALHOST -DNO_ABORT
+      TFLAGS: ${{ matrix.select }} -DMQTT_LOCALHOST -DNO_ABORT 
     steps:
     - uses: actions/checkout@v5
       with: { fetch-depth: 2 }
     - uses: webfactory/ssh-agent@v0.10.0
       with:
             ssh-private-key: ${{ secrets.HEALTH_TESTS_SSH_KEY }}
-    - run: ./test/setup_mqtt_server.sh && make -C test ${{ matrix.target }} > log
+    - run: if [ "${{ matrix.target }}" == "mingw" ]; then export TFLAGS="$TFLAGS -DNO_ZU_TEST"; fi && ./test/setup_mqtt_server.sh && make -C test ${{ matrix.target }} > log
     - if: success() || failure()
       run: |
         cat log
diff --git a/test/unit_test.c b/test/unit_test.c
index 9f3c9aff..b632ec83 100644
--- a/test/unit_test.c
+++ b/test/unit_test.c
@@ -2321,8 +2321,8 @@ static void test_str(void) {
     ASSERT(chkdbl(mg_str("123e-3"), 0.123));
   }
 
-#if defined(_MSC_VER) && _MSC_VER < 1700
-  // VC98 does not have '%zu'
+#if defined(NO_ZU_TEST) || (defined(_MSC_VER) && _MSC_VER < 1700)
+  // VC98 does not have '%zu', some old compilers may also not support it
 #else
   ASSERT(sn("%zu", 0));
   ASSERT(sn("%zu", -1));