fix: reject empty dependsOn arrays and improve flowInput access patterns

[jumski]

Prevent empty dependsOn arrays in Flow steps

This PR improves type safety by rejecting empty dependsOn: [] arrays at compile time. Empty dependency arrays are semantically meaningless (if a step has no dependencies, it should omit dependsOn entirely) and create a type mismatch between TypeScript and runtime behavior.

The changes:

1. Modified the Flow DSL type definitions to require at least one dependency in dependsOn arrays using the [Deps, ...Deps[]] syntax
2. Added type tests to verify that empty dependency arrays are rejected at compile time
3. Updated documentation to clarify that ctx.flowInput is lazy-loaded and should be awaited
4. Improved examples in documentation to show the proper pattern of const flowInput = await ctx.flowInput
5. Enhanced the array processing documentation to explain the performance implications of accessing flow input in map handlers

This change helps prevent a subtle bug where TypeScript would infer an empty object type for dependencies with dependsOn: [], but at runtime the step would receive the flow input instead.

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Latest commit: 3886c6c

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[jumski]

Warning

This pull request is not mergeable via GitHub because a downstack PR is open. Once all requirements are satisfied, merge this PR as a stack on Graphite.
Learn more

• docs: add note about CONNECT_TIMEOUT fix using jsr:@oscar6echo/postgres fork #562
• fix: reject empty dependsOn arrays and improve flowInput access patterns #561 👈 (View in Graphite)
• feat: make flowInput lazy-loaded to prevent data duplication in map steps #560
• feat: asymmetric handler signatures for simpler flow composition #559
• refactor: simplify step input structure by removing run key and using context.flowInput #558
• refactor: rename input parameters to flowInput and deps for clarity #557
• refactor: change step handler input to use asymmetric pattern for better type safety #556
• feat: add flow_input to StepTaskRecord and context objects #555
• feat: add flow_input field to step_task_record for direct access to original input #554
• main

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☁️ Nx Cloud last updated this comment at 2025-12-25 23:11:49 UTC

[github-actions]

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