fix: block Podman on macOS and remove ghcr.io default

- Add platform check in PodmanCLI.__init__() that raises FuzzForgeError
  on macOS with instructions to use Docker instead
- Change RegistrySettings.url default from "ghcr.io/fuzzinglabs" to ""
  (empty string) for local-only mode since no images are published yet
- Update _ensure_module_image() to show helpful error when image not
  found locally and no registry configured
- Update tests to mock Linux platform for Podman tests
- Add root ruff.toml to fix broken configuration in fuzzforge-runner

fuzzforge-common/src/fuzzforge_common/sandboxes/engines/docker/cli.py

@@ -96,7 +96,7 @@ class DockerCLI(AbstractFuzzForgeSandboxEngine):
                 
             reference = f"{repo}:{tag}"
 
-            if filter_prefix and not reference.startswith(filter_prefix):
+            if filter_prefix and filter_prefix not in reference:
                 continue
 
             images.append(

fuzzforge-common/src/fuzzforge_common/sandboxes/engines/podman/cli.py

@@ -39,6 +39,7 @@ def _is_running_under_snap() -> bool:
     Note: Snap only exists on Linux, so this also handles macOS implicitly.
     """
     import os  # noqa: PLC0415
+
     return os.getenv("SNAP") is not None
 
 
@@ -69,15 +70,23 @@ class PodmanCLI(AbstractFuzzForgeSandboxEngine):
         :param runroot: Path to container runtime state.
 
         Custom storage is used when running under Snap AND paths are provided.
+
+        :raises FuzzForgeError: If running on macOS (Podman not supported).
         """
+        import sys  # noqa: PLC0415
+
+        if sys.platform == "darwin":
+            msg = (
+                "Podman is not supported on macOS. Please use Docker instead:\n"
+                "  brew install --cask docker\n"
+                "  # Or download from https://docker.com/products/docker-desktop"
+            )
+            raise FuzzForgeError(msg)
+
         AbstractFuzzForgeSandboxEngine.__init__(self)
 
         # Use custom storage only under Snap (to fix XDG_DATA_HOME issues)
-        self.__use_custom_storage = (
-            _is_running_under_snap() 
-            and graphroot is not None 
-            and runroot is not None
-        )
+        self.__use_custom_storage = _is_running_under_snap() and graphroot is not None and runroot is not None
 
         if self.__use_custom_storage:
             self.__graphroot = graphroot
@@ -98,8 +107,10 @@ class PodmanCLI(AbstractFuzzForgeSandboxEngine):
         if self.__use_custom_storage and self.__graphroot and self.__runroot:
             return [
                 "podman",
-                "--root", str(self.__graphroot),
-                "--runroot", str(self.__runroot),
+                "--root",
+                str(self.__graphroot),
+                "--runroot",
+                str(self.__runroot),
             ]
         return ["podman"]
 

fuzzforge-common/tests/unit/engines/test_podman.py

@@ -2,28 +2,37 @@
 
 import os
 import shutil
+import sys
 import uuid
 from pathlib import Path
 from unittest import mock
 
 import pytest
 
+from fuzzforge_common.exceptions import FuzzForgeError
 from fuzzforge_common.sandboxes.engines.podman.cli import PodmanCLI, _is_running_under_snap
 
 
+# Helper to mock Linux platform for testing (since Podman is Linux-only)
+def _mock_linux_platform() -> mock._patch[str]:
+    """Context manager to mock sys.platform as 'linux'."""
+    return mock.patch.object(sys, "platform", "linux")
+
+
 @pytest.fixture
 def podman_cli_engine() -> PodmanCLI:
     """Create a PodmanCLI engine with temporary storage.
 
     Uses short paths in /tmp to avoid podman's 50-char runroot limit.
     Simulates Snap environment to test custom storage paths.
+    Mocks Linux platform since Podman is Linux-only.
     """
     short_id = str(uuid.uuid4())[:8]
     graphroot = Path(f"/tmp/ff-{short_id}/storage")
     runroot = Path(f"/tmp/ff-{short_id}/run")
 
-    # Simulate Snap environment for testing
-    with mock.patch.dict(os.environ, {"SNAP": "/snap/code/123"}):
+    # Simulate Snap environment for testing on Linux
+    with _mock_linux_platform(), mock.patch.dict(os.environ, {"SNAP": "/snap/code/123"}):
         engine = PodmanCLI(graphroot=graphroot, runroot=runroot)
 
     yield engine
@@ -48,6 +57,15 @@ def test_snap_detection_when_snap_not_set() -> None:
         assert _is_running_under_snap() is False
 
 
+def test_podman_cli_blocks_macos() -> None:
+    """Test that PodmanCLI raises error on macOS."""
+    with mock.patch.object(sys, "platform", "darwin"):
+        with pytest.raises(FuzzForgeError) as exc_info:
+            PodmanCLI()
+        assert "Podman is not supported on macOS" in str(exc_info.value)
+        assert "Docker" in str(exc_info.value)
+
+
 def test_podman_cli_creates_storage_directories_under_snap() -> None:
     """Test that PodmanCLI creates storage directories when under Snap."""
     short_id = str(uuid.uuid4())[:8]
@@ -57,8 +75,8 @@ def test_podman_cli_creates_storage_directories_under_snap() -> None:
     assert not graphroot.exists()
     assert not runroot.exists()
 
-    with mock.patch.dict(os.environ, {"SNAP": "/snap/code/123"}):
-        engine = PodmanCLI(graphroot=graphroot, runroot=runroot)
+    with _mock_linux_platform(), mock.patch.dict(os.environ, {"SNAP": "/snap/code/123"}):
+        PodmanCLI(graphroot=graphroot, runroot=runroot)
 
     assert graphroot.exists()
     assert runroot.exists()
@@ -73,7 +91,7 @@ def test_podman_cli_base_cmd_under_snap() -> None:
     graphroot = Path(f"/tmp/ff-{short_id}/storage")
     runroot = Path(f"/tmp/ff-{short_id}/run")
 
-    with mock.patch.dict(os.environ, {"SNAP": "/snap/code/123"}):
+    with _mock_linux_platform(), mock.patch.dict(os.environ, {"SNAP": "/snap/code/123"}):
         engine = PodmanCLI(graphroot=graphroot, runroot=runroot)
         base_cmd = engine._base_cmd()
 
@@ -93,7 +111,7 @@ def test_podman_cli_base_cmd_without_snap() -> None:
 
     env = os.environ.copy()
     env.pop("SNAP", None)
-    with mock.patch.dict(os.environ, env, clear=True):
+    with _mock_linux_platform(), mock.patch.dict(os.environ, env, clear=True):
         engine = PodmanCLI(graphroot=graphroot, runroot=runroot)
         base_cmd = engine._base_cmd()
 
@@ -106,8 +124,9 @@ def test_podman_cli_base_cmd_without_snap() -> None:
 
 def test_podman_cli_default_mode() -> None:
     """Test PodmanCLI without custom storage paths."""
-    engine = PodmanCLI()  # No paths provided
-    base_cmd = engine._base_cmd()
+    with _mock_linux_platform():
+        engine = PodmanCLI()  # No paths provided
+        base_cmd = engine._base_cmd()
 
     assert base_cmd == ["podman"]
     assert "--root" not in base_cmd

fuzzforge-runner/src/fuzzforge_runner/executor.py

@@ -198,7 +198,7 @@ class ModuleExecutor:
         # Default fallback
         return f"localhost/{module_identifier}:latest"
 
-    def _pull_module_image(self, module_identifier: str, registry_url: str = "ghcr.io/fuzzinglabs", tag: str = "latest") -> None:
+    def _pull_module_image(self, module_identifier: str, registry_url: str, tag: str = "latest") -> None:
         """Pull a module image from the container registry.
 
         :param module_identifier: Name/identifier of the module to pull.
@@ -238,13 +238,13 @@ class ModuleExecutor:
             )
             raise SandboxError(message) from exc
 
-    def _ensure_module_image(self, module_identifier: str, registry_url: str = "ghcr.io/fuzzinglabs", tag: str = "latest") -> None:
+    def _ensure_module_image(self, module_identifier: str, registry_url: str = "", tag: str = "latest") -> None:
         """Ensure module image exists, pulling it if necessary.
 
         :param module_identifier: Name/identifier of the module image.
-        :param registry_url: Container registry URL to pull from.
+        :param registry_url: Container registry URL to pull from (empty = local-only mode).
         :param tag: Image tag to pull.
-        :raises SandboxError: If image check or pull fails.
+        :raises SandboxError: If image not found locally and no registry configured.
 
         """
         logger = get_logger()
@@ -253,6 +253,15 @@ class ModuleExecutor:
             logger.debug("module image exists locally", module=module_identifier)
             return
 
+        # If no registry configured, we're in local-only mode
+        if not registry_url:
+            raise SandboxError(
+                f"Module image '{module_identifier}' not found locally.\n"
+                "Build it with: make build-modules\n"
+                "\n"
+                "Or configure a registry URL via FUZZFORGE_REGISTRY__URL environment variable."
+            )
+
         logger.info(
             "module image not found locally, pulling from registry",
             module=module_identifier,
@@ -332,6 +341,7 @@ class ModuleExecutor:
         try:
             # Create temporary directory - caller must clean it up after container finishes
             from tempfile import mkdtemp
+
             temp_path = Path(mkdtemp(prefix="fuzzforge-input-"))
 
             # Copy assets to temp directory
@@ -341,16 +351,19 @@ class ModuleExecutor:
                     if assets_path.suffix == ".gz" or assets_path.name.endswith(".tar.gz"):
                         # Extract archive contents
                         import tarfile
+
                         with tarfile.open(assets_path, "r:gz") as tar:
                             tar.extractall(path=temp_path)
                         logger.debug("extracted tar.gz archive", archive=str(assets_path))
                     else:
                         # Single file - copy it
                         import shutil
+
                         shutil.copy2(assets_path, temp_path / assets_path.name)
                 else:
                     # Directory - copy all files (including subdirectories)
                     import shutil
+
                     for item in assets_path.iterdir():
                         if item.is_file():
                             shutil.copy2(item, temp_path / item.name)
@@ -363,19 +376,23 @@ class ModuleExecutor:
                 if item.name == "input.json":
                     continue
                 if item.is_file():
-                    resources.append({
-                        "name": item.stem,
-                        "description": f"Input file: {item.name}",
-                        "kind": "unknown",
-                        "path": f"/data/input/{item.name}",
-                    })
+                    resources.append(
+                        {
+                            "name": item.stem,
+                            "description": f"Input file: {item.name}",
+                            "kind": "unknown",
+                            "path": f"/data/input/{item.name}",
+                        }
+                    )
                 elif item.is_dir():
-                    resources.append({
-                        "name": item.name,
-                        "description": f"Input directory: {item.name}",
-                        "kind": "unknown",
-                        "path": f"/data/input/{item.name}",
-                    })
+                    resources.append(
+                        {
+                            "name": item.name,
+                            "description": f"Input directory: {item.name}",
+                            "kind": "unknown",
+                            "path": f"/data/input/{item.name}",
+                        }
+                    )
 
             # Create input.json with settings and resources
             input_data = {
@@ -461,6 +478,7 @@ class ModuleExecutor:
         try:
             # Create temporary directory for results
             from tempfile import mkdtemp
+
             temp_dir = Path(mkdtemp(prefix="fuzzforge-results-"))
 
             # Copy entire output directory from container
@@ -489,6 +507,7 @@ class ModuleExecutor:
 
             # Clean up temp directory
             import shutil
+
             shutil.rmtree(temp_dir, ignore_errors=True)
 
             logger.info("results pulled successfully", sandbox=sandbox, archive=str(archive_path))
@@ -571,6 +590,7 @@ class ModuleExecutor:
                 self.terminate_sandbox(sandbox)
             if input_dir and input_dir.exists():
                 import shutil
+
                 shutil.rmtree(input_dir, ignore_errors=True)
 
     # -------------------------------------------------------------------------
@@ -669,4 +689,5 @@ class ModuleExecutor:
             self.terminate_sandbox(container_id)
             if input_dir:
                 import shutil
+
                 shutil.rmtree(input_dir, ignore_errors=True)

fuzzforge-runner/src/fuzzforge_runner/settings.py

@@ -60,10 +60,15 @@ class ProjectSettings(BaseModel):
 
 
 class RegistrySettings(BaseModel):
-    """Container registry configuration for module images."""
+    """Container registry configuration for module images.
 
-    #: Registry URL for pulling module images.
-    url: str = Field(default="ghcr.io/fuzzinglabs")
+    By default, registry URL is empty (local-only mode). When empty,
+    modules must be built locally with `make build-modules`.
+    Set via FUZZFORGE_REGISTRY__URL environment variable if needed.
+    """
+
+    #: Registry URL for pulling module images (empty = local-only mode).
+    url: str = Field(default="")
 
     #: Default tag to use when pulling images.
     default_tag: str = Field(default="latest")

ruff.toml

@@ -0,0 +1,20 @@
+line-length = 120
+
+[lint]
+select = [ "ALL" ]
+ignore = [
+    "COM812",   # conflicts with the formatter
+    "D100",     # ignoring missing docstrings in public modules
+    "D104",     # ignoring missing docstrings in public packages
+    "D203",     # conflicts with 'D211'
+    "D213",     # conflicts with 'D212'
+    "TD002",    # ignoring missing author in 'TODO' statements
+    "TD003",    # ignoring missing issue link in 'TODO' statements
+]
+
+[lint.per-file-ignores]
+"tests/*" = [
+    "ANN401",   # allowing 'typing.Any' to be used to type function parameters in tests
+    "PLR2004",  # allowing comparisons using unamed numerical constants in tests
+    "S101",     # allowing 'assert' statements in tests
+]