attune/work-summary/2026-03-04-typed-publish-directives.md

Typed Publish Directives in Workflow Definitions

Date: 2026-03-04

Problem

The python_example.timeline_demo workflow action failed to execute with:

Runtime not found: No runtime found for action: python_example.timeline_demo
(available: node.js, python, shell)

This error was misleading — the real issue was that the workflow definition YAML failed to parse during pack registration, so the workflow_definition record was never created and the action's workflow_def FK remained NULL. Without a linked workflow definition, the executor treated it as a regular action and dispatched it to a worker, which couldn't find a runtime for a workflow action.

Root Cause

The YAML parsing error was:

tasks[7].next[0].publish: data did not match any variant of untagged enum
PublishDirective at line 234 column 11

The PublishDirective::Simple variant was defined as HashMap<String, String>, but the workflow YAML contained non-string publish values:

publish:
  - validation_passed: true    # boolean, not a string
  - validation_passed: false   # boolean, not a string

YAML parses true/false as booleans, which couldn't deserialize into String.

Solution

Changed PublishDirective::Simple from HashMap<String, String> to HashMap<String, serde_json::Value> so publish directives can carry any JSON-compatible type: strings (including template expressions), booleans, numbers, arrays, objects, and null.

Files Modified

File	Change
crates/common/src/workflow/parser.rs	PublishDirective::Simple value type → serde_json::Value
crates/executor/src/workflow/parser.rs	Same change (executor's local copy)
crates/executor/src/workflow/graph.rs	Renamed PublishVar.expression: String → PublishVar.value: JsonValue with #[serde(alias = "expression")] for backward compat with stored task graphs; imported serde_json::Value
crates/executor/src/scheduler.rs	Updated publish map from HashMap<String, String> to HashMap<String, JsonValue>
crates/executor/src/workflow/context.rs	publish_from_result accepts HashMap<String, JsonValue>, passes values directly to render_json (strings get template-rendered, non-strings pass through unchanged)
crates/common/src/workflow/expression_validator.rs	Only validates string values as templates; non-string literals are skipped
packs.external/python_example/actions/workflows/timeline_demo.yaml	Fixed result().items → result().data.items (secondary bug in workflow definition)

Type Preservation

The rendering pipeline now correctly preserves types end-to-end:

• String values (e.g., "{{ result().data }}") → rendered through expression engine with type preservation
• Boolean values (e.g., true) → stored as JsonValue::Bool(true), pass through render_json unchanged
• Numeric values (e.g., 42, 3.14) → stored as JsonValue::Number, pass through unchanged
• Null → stored as JsonValue::Null, passes through unchanged
• Arrays/Objects → stored as-is, with any nested string templates rendered recursively

Tests Added

• parser::tests::test_typed_publish_values_in_transitions — verifies YAML parsing of booleans, numbers, strings, templates, and null in publish directives
• graph::tests::test_typed_publish_values — verifies typed values survive graph construction
• context::tests::test_publish_typed_values — verifies typed values pass through publish_from_result with correct types (boolean stays boolean, not string "true")

Verification

After deploying the fix:

1. Re-registered python_example pack — workflow definition created successfully (ID: 2)
2. Action python_example.timeline_demo linked to workflow_def = 2
3. Executed the workflow — executor correctly identified it as a workflow action and orchestrated 15 child task executions through all stages: initialize → parallel fan-out (build/lint/scan) → merge join → generate items → with_items(×3) → validate → finalize
4. Workflow variables confirmed type preservation: validation_passed: true (boolean), items_processed: 3 (integer), number_list: [1, 2, 3] (array)