fix(workflows): guard non-mapping 'workflow:' block in WorkflowDefinition

A present-but-non-mapping top-level `workflow:` block (bare `workflow:` ->
YAML null, or `workflow: <str>` / `workflow: [..]`) crashed
WorkflowDefinition.__init__ with AttributeError: the `{}` default of
`data.get("workflow", {})` only applies when the key is ABSENT, so a non-dict
value reached `workflow.get("id", ...)`. This fires inside from_yaml/
from_string — before validate_workflow can report the malformed shape — and
in the CLI escapes as a raw traceback (load_workflow is wrapped to catch only
FileNotFoundError/ValueError).

Normalize the local `workflow` to {} when it is not a mapping (self.data keeps
the raw value so validate_workflow still reports it), mirroring the adjacent
default_options guard.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: jawwad-ali

src/specify_cli/workflows/engine.py

@@ -42,6 +42,14 @@ def __init__(self, data: dict[str, Any], source_path: Path | None = None) -> Non
         self.source_path = source_path
 
         workflow = data.get("workflow", {})
+        # A present-but-non-mapping ``workflow:`` block (bare ``workflow:`` ->
+        # None, or ``workflow: <str/list>``) would crash the following
+        # ``workflow.get(...)`` calls with AttributeError before validate can
+        # report the malformed shape. Normalize the local to {} (self.data
+        # keeps the raw value for validate_workflow), mirroring the
+        # default_options guard below.
+        if not isinstance(workflow, dict):
+            workflow = {}
         self.id: str = workflow.get("id", "")
         self.name: str = workflow.get("name", "")
         self.version: str = workflow.get("version", "0.0.0")

tests/test_workflows.py

@@ -3590,6 +3590,23 @@ def test_from_string(self, sample_workflow_yaml):
         assert definition.id == "test-workflow"
         assert len(definition.inputs) == 2
 
+    @pytest.mark.parametrize(
+        "block", ["workflow:\nsteps: []\n", "workflow: hi\nsteps: []\n", "workflow: [a]\nsteps: []\n"]
+    )
+    def test_non_mapping_workflow_block_parses_then_validates(self, block):
+        # A present-but-non-mapping `workflow:` block must not crash construction
+        # with AttributeError; it should parse (empty header) and let
+        # validate_workflow report the missing id/name, mirroring how the other
+        # raw fields are validated later.
+        from specify_cli.workflows.engine import WorkflowDefinition, validate_workflow
+
+        definition = WorkflowDefinition.from_string(block)  # must not raise
+        assert definition.id == ""
+        errors = validate_workflow(definition)
+        assert any("workflow.id" in e for e in errors)
+        # The raw value is preserved on .data for validation/inspection.
+        assert "workflow" in definition.data
+
     def test_from_string_invalid(self):
         from specify_cli.workflows.engine import WorkflowDefinition