attune/work-summary/2026-02-05-rust-min-stack-and-workflow-file-separation.md

RUST_MIN_STACK Fix & Workflow File Metadata Separation

Date: 2026-02-05

Summary

Three related changes: (1) fixed rustc SIGSEGV crashes during Docker release builds by increasing the compiler stack size, (2) enforced the separation of concerns between action YAML and workflow YAML files across the parser, loaders, and registrars, and (3) updated the workflow builder UI and API save endpoints to produce the correct two-file layout.

Problem 1: rustc SIGSEGV in Docker Builds

Docker Compose builds were failing with rustc interrupted by SIGSEGV during release compilation. The error message suggested increasing RUST_MIN_STACK to 16 MiB.

Fix

Added ENV RUST_MIN_STACK=16777216 to the build stage of all 7 Rust Dockerfiles:

• docker/Dockerfile (both build stages)
• docker/Dockerfile.optimized
• docker/Dockerfile.worker
• docker/Dockerfile.worker.optimized
• docker/Dockerfile.sensor.optimized
• docker/Dockerfile.pack-binaries
• docker/Dockerfile.pack-builder

Also added export RUST_MIN_STACK := 16777216 to the Makefile for local builds.

Problem 2: Workflow File Metadata Duplication

The timeline_demo.yaml workflow file (in actions/workflows/) redundantly defined ref, label, description, parameters, output, and tags — all of which are action-level concerns that belong exclusively in the companion action YAML (actions/timeline_demo.yaml). This violated the design principle that action YAML owns the interface and workflow YAML owns the execution graph.

The root cause was that WorkflowDefinition required ref and label as mandatory fields, forcing even action-linked workflow files to include them.

Backend Parser & Loader Changes

crates/common/src/workflow/parser.rs:

• Made ref and label optional with #[serde(default)] and removed min = 1 validators
• Added two new tests: test_parse_action_linked_workflow_without_ref_and_label and test_parse_standalone_workflow_still_works_with_ref_and_label

crates/common/src/pack_registry/loader.rs:

• load_workflow_for_action() now fills in ref/label/description/tags from the action YAML when the workflow file omits them (action YAML is authoritative)

crates/common/src/workflow/registrar.rs and crates/executor/src/workflow/registrar.rs:

• Added effective_ref() and effective_label() helper methods that fall back to WorkflowFile.ref_name / WorkflowFile.name (derived from filename) when the workflow YAML omits them
• Threaded effective values through create_workflow, update_workflow, create_companion_action, and ensure_companion_action

scripts/load_core_pack.py:

• upsert_workflow_definition() now derives ref/label/description/tags from the action YAML when the workflow file omits them

packs.external/python_example/actions/workflows/timeline_demo.yaml:

• Stripped ref, label, description, parameters, output, and tags — file now contains only version, vars, tasks, and output_map

Problem 3: Workflow Builder Wrote Full Definition to Disk

The visual workflow builder's save endpoints (POST /api/v1/packs/{pack_ref}/workflow-files and PUT /api/v1/workflows/{ref}/file) were writing the full WorkflowYamlDefinition — including action-level metadata — to the .workflow.yaml file on disk. The YAML viewer also showed a single monolithic preview.

API Save Endpoint Changes

crates/api/src/routes/workflows.rs — write_workflow_yaml():

• Now writes two files per save:
  1. Workflow YAML (actions/workflows/{name}.workflow.yaml) — graph-only via strip_action_level_fields() which removes ref, label, description, parameters, output, tags
  2. Action YAML (actions/{name}.yaml) — action-level metadata via build_action_yaml() which produces ref, label, description, enabled, workflow_file, parameters, output, tags
• Added strip_action_level_fields() helper — extracts only version, vars, tasks, output_map from the definition JSON
• Added build_action_yaml() helper — constructs the companion action YAML with proper formatting and comments

Frontend Changes

web/src/types/workflow.ts:

• Added WorkflowGraphDefinition interface (graph-only: version, vars, tasks, output_map)
• Added ActionYamlDefinition interface (action metadata: ref, label, description, enabled, workflow_file, parameters, output, tags)
• Added builderStateToGraph() — extracts graph-only definition from builder state
• Added builderStateToActionYaml() — extracts action metadata from builder state
• Refactored builderStateToDefinition() to delegate to builderStateToGraph() internally

web/src/pages/actions/WorkflowBuilderPage.tsx:

• YAML viewer now shows two side-by-side panels instead of a single preview:
  • Left panel (blue, 2/5 width): Action YAML — shows actions/{name}.yaml content with ref, label, parameters, workflow_file reference
  • Right panel (green, 3/5 width): Workflow YAML — shows actions/workflows/{name}.workflow.yaml with graph-only content (version, vars, tasks)
• Each panel has its own copy button, filename label, and description bar explaining the file's role
• Separate actionYamlPreview and workflowYamlPreview memos replace the old yamlPreview

Design: Two Valid Workflow File Conventions

1. Standalone workflows (workflows/*.yaml) — no companion action YAML, so they carry their own ref, label, parameters, etc. Loaded by WorkflowLoader.sync_pack_workflows().

2. Action-linked workflows (actions/workflows/*.yaml) — referenced via workflow_file from an action YAML. The action YAML is the single authoritative source for ref, label, description, parameters, output, and tags. The workflow file contains only the execution graph: version, vars, tasks, output_map.

The visual workflow builder and API save endpoints now produce the action-linked layout (convention 2) with properly separated files.

Files Changed

File	Change
docker/Dockerfile	Added RUST_MIN_STACK=16777216 (both stages)
docker/Dockerfile.optimized	Added RUST_MIN_STACK=16777216
docker/Dockerfile.worker	Added RUST_MIN_STACK=16777216
docker/Dockerfile.worker.optimized	Added RUST_MIN_STACK=16777216
docker/Dockerfile.sensor.optimized	Added RUST_MIN_STACK=16777216
docker/Dockerfile.pack-binaries	Added RUST_MIN_STACK=16777216
docker/Dockerfile.pack-builder	Added RUST_MIN_STACK=16777216
Makefile	Added export RUST_MIN_STACK
crates/common/src/workflow/parser.rs	Optional ref/label, 2 new tests
crates/common/src/pack_registry/loader.rs	Action YAML fallback for metadata
crates/common/src/workflow/registrar.rs	effective_ref()/effective_label()
crates/executor/src/workflow/registrar.rs	effective_ref()/effective_label()
scripts/load_core_pack.py	Action YAML fallback for metadata
crates/api/src/routes/workflows.rs	Two-file write, strip_action_level_fields(), build_action_yaml()
web/src/types/workflow.ts	WorkflowGraphDefinition, ActionYamlDefinition, builderStateToGraph(), builderStateToActionYaml()
web/src/pages/actions/WorkflowBuilderPage.tsx	Two-panel YAML viewer
packs.external/python_example/actions/workflows/timeline_demo.yaml	Stripped action-level metadata
AGENTS.md	Updated Workflow File Storage, YAML viewer, Docker Build Optimization sections

Test Results

• All 23 parser tests pass (including 2 new)
• All 9 loader tests pass
• All 2 registrar tests pass
• All 598 workspace lib tests pass
• Zero TypeScript errors
• Zero compiler warnings
• Zero build errors