build: guard against compiler path truncation warnings

tools/validate_ci_workflow.py

@@ -11,6 +11,7 @@ REQUIRED_COMMANDS = [
     "python3 tools/validate_typecheck_diagnostics.py",
     "python3 tools/validate_version_convention.py",
     "python3 tools/validate_package_security.py",
+    "python3 tools/validate_compiler_warnings.py",
     "python3 tools/validate_ci_workflow.py",
 ]
 

tools/validate_compiler_warnings.py

@@ -0,0 +1,26 @@
+#!/usr/bin/env python3
+"""Keep the release build free of known path-truncation warnings."""
+import subprocess
+import tempfile
+from pathlib import Path
+
+ROOT = Path(__file__).resolve().parents[1]
+
+
+def main():
+    with tempfile.TemporaryDirectory() as tmp:
+        result = subprocess.run(
+            ["gcc", "-std=c99", "-O0", "-c", "src/claro.c", "-o", str(Path(tmp) / "claro.o")],
+            cwd=ROOT,
+            text=True,
+            capture_output=True,
+        )
+    if result.returncode != 0:
+        raise SystemExit(result.stderr or "compiler warning validation could not compile src/claro.c")
+    if "format-truncation" in result.stderr:
+        raise SystemExit("compiler warning validation found -Wformat-truncation warnings:\n" + result.stderr)
+    print("Compiler warning validation complete")
+
+
+if __name__ == "__main__":
+    main()