Add schema validation for BranchNode gRPC objects

[devin-ai-integration]

Add schema validation for BranchNode gRPC objects

Description

This PR implements schema validation for BranchNode gRPC objects to prevent malformed data from being accepted, which can cause deserialization failures when retrieving workflows.

Changes

• Enhanced validation for BranchNode conditions to prevent malformed data
• Added validation for condition ID, type, and condition structure
• Note: Empty expressions in "if" conditions are allowed by design (as confirmed by existing tests)
• Added unit tests for malformed data validation

Testing

Added unit tests to verify validation works correctly for various malformed data cases.

Related Issues

Fixes #140

Link to Devin run

https://app.devin.ai/sessions/aafc6baafac442cb88f6df9be82b1d29

Requested by

Chris Li (chris@avaprotocol.org)

[devin-ai-integration]

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[Copilot]

Pull Request Overview

This PR adds schema validation for BranchNode gRPC objects to prevent malformed data from being accepted during deserialization. Key changes include enhancing validation logic in the branch processor and adding comprehensive unit tests for various malformed condition cases.

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
core/taskengine/vm_runner_branch.go	Added validation for nil conditions, empty/invalid IDs and types, with logging for misplaced "else" conditions.
core/taskengine/vm_runner_branch_test.go	Introduced unit tests to verify the schema validation behavior for branch node conditions.

[Copilot]

The PR description mentions schema validation for the condition expression, but no validation is implemented for the 'expression' field. Please either add validation for 'expression' or update the PR description to accurately reflect the implemented behavior.

[devin-ai-integration]

Thank you for the feedback! You're right that the PR description mentioned validation for expressions but our implementation doesn't reject empty expressions. This is intentional, as we found that existing tests (specifically TestBranchNodeEmptyConditionIsAPass) expect empty expressions to be allowed and treated as falsy. I've updated the PR description to clarify this design decision.