Stabilize the real-Windows (MSYS2) CI job: green build + gating

.github/workflows/build-and-test.yml

@@ -125,6 +125,21 @@ jobs:
     # one alongside ours) would be a malformed resource directory; zero means
     # the *A APIs never switch to UTF-8. wrestool (icoutils) lists and extracts
     # the resource; --raw dumps the manifest bytes verbatim for the content grep.
+    # The MinGW build embeds a PREBUILT src/mcp-w32s.res (so the MSYS2 native
+    # runner needs no windres preprocessor, which is broken there on binutils
+    # 2.46). Guard the committed artifact against drift: regenerate the .res from
+    # the .rc + .manifest here - where the cross windres preprocessor works - and
+    # byte-diff. A stale .res fails the build and prints the regen command.
+    - name: Verify the prebuilt manifest .res matches its source
+      run: |
+        i686-w64-mingw32-windres -I src src/mcp-w32s.rc -O res -o /tmp/regen.res
+        if ! cmp -s /tmp/regen.res src/mcp-w32s.res; then
+          echo "ERROR: src/mcp-w32s.res is stale - regenerate it:"
+          echo "  i686-w64-mingw32-windres -I src src/mcp-w32s.rc -O res -o src/mcp-w32s.res"
+          exit 1
+        fi
+        echo "OK: prebuilt manifest .res matches mcp-w32s.rc + mcp-w32s.manifest."
+
     - name: Verify exactly one UTF-8 activeCodePage manifest at RT_MANIFEST ID 1
       run: |
         N=$(wrestool -l build/mingw/mcp-w32s.exe | grep -c -- '--type=24 --name=1' || true)
@@ -444,10 +459,13 @@ jobs:
   windows-native:
     name: real-Windows (exec / Winsock / ConPTY, no Wine)
     runs-on: windows-latest
-    # Newly introduced job, still being stabilised on the MSYS2 toolchain - keep
-    # it informational so it cannot gate merges until it is reliably green; flip
-    # to a required check once the real-Windows run is consistently passing.
-    continue-on-error: true
+    # Gating (no longer continue-on-error): the manifest is embedded from a
+    # prebuilt .res (no windres preprocessor), the import check uses the
+    # MSYS2-unprefixed objdump, and the shell-builtin tests use a host-robust
+    # subject - so this job builds and runs the full exec/Winsock/ConPTY suite
+    # green on real Windows. It was informational while the MSYS2 toolchain was
+    # being stabilised. (Add it to the branch-protection required checks to make
+    # it a hard merge gate.)
     defaults:
       run:
         shell: msys2 {0}
@@ -469,7 +487,9 @@ jobs:
         cmake --build --preset mingw
     - name: Verify the device still imports ONLY kernel32 + user32
       run: |
-        IMPORTS=$(i686-w64-mingw32-objdump -p build/mingw/mcp-w32s.exe \
+        # MSYS2 MINGW32 ships UNPREFIXED binutils (objdump, not
+        # i686-w64-mingw32-objdump - the cross-prefixed name does not exist here).
+        IMPORTS=$(objdump -p build/mingw/mcp-w32s.exe \
           | sed -n 's/.*DLL Name: //p' | tr 'A-Z' 'a-z' | sort -u)
         echo "imports: $IMPORTS"
         echo "$IMPORTS" | grep -vqE '^(kernel32|user32)\.dll$' && {

CMakeLists.txt

@@ -15,10 +15,37 @@
 cmake_minimum_required(VERSION 3.21)
 project(mcp-w32s C)
 
-# RC compiles the application manifest (src/mcp-w32s.rc) into mcp-w32s.exe only.
-# windres on MinGW (CMAKE_RC_COMPILER, set by the toolchain) and rc.exe on MSVC
-# both drive a .rc through this language - no per-toolchain special-casing.
-enable_language(RC)
+# RT_MANIFEST (the UTF-8 activeCodePage manifest), embedded in mcp-w32s.exe only.
+# On MSVC, rc.exe compiles src/mcp-w32s.rc directly. On MinGW the manifest is
+# shipped as a PREBUILT, byte-deterministic resource (src/mcp-w32s.res, generated
+# from mcp-w32s.rc + mcp-w32s.manifest): compiling the committed .res to a coff
+# object needs NO preprocessor, so it builds on every runner - including the
+# MSYS2 native-Windows CI runner whose windres (binutils 2.46) cannot spawn a
+# preprocessor to compile the .rc directly ("CreateProcess failed: The system
+# cannot find the file specified", even with a full-path .exe). The SAME manifest
+# lands in every binary; the Ubuntu CI job regenerates the .res from source and
+# byte-diffs it, so the committed artifact can never drift from the .rc/.manifest.
+enable_language(RC)   # MSVC: rc.exe compiles the .rc. (MinGW uses the .res below.)
+if(MSVC)
+  set(MCP_MANIFEST src/mcp-w32s.rc)
+else()
+  # Resolve windres to a FULL PATH. The custom command below runs via cmd.exe on
+  # the MSYS2 native runner, where a bare `i686-w64-mingw32-windres` is "not
+  # recognized" - CMake's own RC rule resolves it internally, but the
+  # ${CMAKE_RC_COMPILER} variable stays the bare toolchain name. find_program runs
+  # at configure time in the MSYS2 PATH and yields the full path cmd.exe can spawn.
+  find_program(MCP_WINDRES NAMES "${CMAKE_RC_COMPILER}" windres REQUIRED)
+  set(MCP_MANIFEST ${CMAKE_BINARY_DIR}/mcp-w32s_manifest.obj)
+  add_custom_command(
+    OUTPUT ${MCP_MANIFEST}
+    COMMAND ${MCP_WINDRES} --input-format=res -O coff
+            ${CMAKE_CURRENT_SOURCE_DIR}/src/mcp-w32s.res ${MCP_MANIFEST}
+    DEPENDS ${CMAKE_CURRENT_SOURCE_DIR}/src/mcp-w32s.res
+    COMMENT "Embedding the prebuilt RT_MANIFEST (res -> coff, no preprocessor)"
+    VERBATIM)
+  set_source_files_properties(${MCP_MANIFEST} PROPERTIES
+    EXTERNAL_OBJECT TRUE GENERATED TRUE)
+endif()
 
 # C89 strict, no GNU extensions (matches the historic -std=c89 -pedantic).
 set(CMAKE_C_STANDARD 90)
@@ -95,11 +122,11 @@ set(CORE_SOURCES
 # never on Win32s. The VC6 toolchain path is unchanged.
 # (Phase 6 Finding #1 remediation; see plan/PHASE6.md in the host repo.)
 if(CMAKE_C_COMPILER_ID STREQUAL "GNU")
-    add_executable(mcp-w32s src/mcp-w32s.c ${CORE_SOURCES} src/mini_crt.c src/mcp-w32s.rc)
+    add_executable(mcp-w32s src/mcp-w32s.c ${CORE_SOURCES} src/mini_crt.c ${MCP_MANIFEST})
     target_link_options(mcp-w32s PRIVATE -nostdlib -mconsole)
     target_link_libraries(mcp-w32s PRIVATE kernel32 user32 gcc)
 else()
-    add_executable(mcp-w32s src/mcp-w32s.c ${CORE_SOURCES} src/mcp-w32s.rc)
+    add_executable(mcp-w32s src/mcp-w32s.c ${CORE_SOURCES} ${MCP_MANIFEST})
     target_link_libraries(mcp-w32s PRIVATE kernel32 user32)
 endif()
 

tests/test_binfmt.c

@@ -209,16 +209,19 @@ TEST_CASE(missing_file_errors) {
     TEST_ASSERT(err[0] != '\0', "error message populated");
 }
 
-/* 6. Shell built-in name ("dir") -> BIN_SHELL without file read */
+/* 6. Shell built-in name -> BIN_SHELL without file read. Use "ver" (a cmd
+ * built-in with no .exe equivalent on ANY host), not "dir": some runners ship a
+ * coreutils dir.exe on PATH (e.g. MSYS2 /usr/bin on the native-Windows CI), so
+ * "dir" correctly resolves to a real PE there - a host-tolerance trap. */
 TEST_CASE(shell_builtin_is_shell) {
     char err[128];
     BinaryType type;
     int ok;
 
     type = BIN_UNKNOWN;
-    ok = BinFmtClassify("dir", &type, err, sizeof(err));
-    TEST_ASSERT_INT_EQUAL(1, ok, "classify 'dir' succeeds");
-    TEST_ASSERT_INT_EQUAL(BIN_SHELL, type, "'dir' is shell built-in");
+    ok = BinFmtClassify("ver", &type, err, sizeof(err));
+    TEST_ASSERT_INT_EQUAL(1, ok, "classify 'ver' succeeds");
+    TEST_ASSERT_INT_EQUAL(BIN_SHELL, type, "'ver' is shell built-in");
 }
 
 /* 7. Uplift: after FeatInit, if pGetBinaryTypeA present, self still PE32. */

tests/test_exec_ops.c

@@ -335,29 +335,32 @@ TEST_CASE(invalid_base64_is_dispatcher)
 }
 
 /* ================================================================
- * #15 - shell=true vs shell=false: dir works only via shell. exec_ops
- *       receives a fully-built command line; the shell decision is the
- *       dispatcher's (decision 3, catalog auto-route). At the exec_ops
- *       layer we verify that "cmd /c dir" works and a bare "dir" (no
- *       shell wrap) spawn-fails - dir is not an .exe.
+ * #15 - shell=true vs shell=false: a cmd built-in works only via shell.
+ *       exec_ops receives a fully-built command line; the shell decision is
+ *       the dispatcher's (decision 3, catalog auto-route). At the exec_ops
+ *       layer we verify that "cmd /c <builtin>" works and a bare "<builtin>"
+ *       (no shell wrap) spawn-fails - the built-in is not an .exe. Use "ver",
+ *       not "dir": some runners ship a coreutils dir.exe on PATH (e.g. MSYS2
+ *       /usr/bin on the native-Windows CI), so a bare "dir" correctly spawns
+ *       that real PE there. "ver" has no .exe equivalent on any host.
  * ================================================================ */
 TEST_CASE(shell_dir_routing)
 {
     ExecResult r;
     char msg[128];
     int ok_shell, ok_bare;
     clear_bufs();
-    ok_shell = ExecOpRun("cmd /c dir", "C:\\", T_TIMEOUT, 1,
+    ok_shell = ExecOpRun("cmd /c ver", "C:\\", T_TIMEOUT, 1,
                          NULL, 0, g_out, sizeof(g_out), g_err, sizeof(g_err),
                          0, 0, BIN_PE32, &r, msg, sizeof(msg));
-    TEST_ASSERT(ok_shell, "dir via shell works");
-    TEST_ASSERT_INT_EQUAL(0, r.exit_code, "shelled dir exit 0");
+    TEST_ASSERT(ok_shell, "ver via shell works");
+    TEST_ASSERT_INT_EQUAL(0, r.exit_code, "shelled ver exit 0");
 
     clear_bufs();
-    ok_bare = ExecOpRun("dir", "C:\\", T_TIMEOUT, 1,
+    ok_bare = ExecOpRun("ver", "C:\\", T_TIMEOUT, 1,
                         NULL, 0, g_out, sizeof(g_out), g_err, sizeof(g_err),
                         0, 0, BIN_PE32, &r, msg, sizeof(msg));
-    TEST_ASSERT(!ok_bare, "bare dir (no .exe) spawn-fails");
+    TEST_ASSERT(!ok_bare, "bare ver (no .exe) spawn-fails");
 }
 
 /* ================================================================

toolchains/mingw-w64-i386.cmake

@@ -17,19 +17,13 @@ set(CMAKE_RC_COMPILER ${TOOLCHAIN_PREFIX}-windres)
 # the PEs run against real cmd.exe/Winsock/ConPTY instead of Wine), the
 # compiler's own sysroot is already correct and the Linux path below does not
 # exist, so leave CMake's default search alone there.
+# (The windres preprocessor is configured universally in CMakeLists.txt - with
+# the resolved full-path compiler - so it bakes the manifest in on both hosts.)
 if(NOT CMAKE_HOST_WIN32)
   set(CMAKE_FIND_ROOT_PATH /usr/${TOOLCHAIN_PREFIX})
   set(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
   set(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
   set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)
-else()
-  # MSYS2's i686 windres fails to spawn its default preprocessor ("CreateProcess
-  # failed: The system cannot find the file specified") when CMake drives it.
-  # Point it at the mingw32 gcc explicitly and use a temp file rather than the
-  # pipe spawn that misbehaves on Windows. (binutils 2.36+ --preprocessor-arg
-  # syntax.) Linux cross-windres needs none of this and is left untouched.
-  set(CMAKE_RC_FLAGS
-      "--use-temp-file --preprocessor=i686-w64-mingw32-gcc --preprocessor-arg=-E --preprocessor-arg=-xc-header --preprocessor-arg=-DRC_INVOKED")
 endif()
 
 # i386-only codegen + the strict warning gate the project has always used.