[plan] Split `expression_validation.go` into three focused files

[github-actions]

Objective

Split pkg/workflow/expression_validation.go (715 lines — 2.4× the 300-line hard limit) into three focused files with clear responsibilities.

Context

From discussion #21398 (Repository Quality Improvement Report - Validator File Size Compliance). This file mixes expression safety orchestration, dangerous-property detection, runtime import path handling, and expression syntax/quote/brace validation.

Approach

Step 1: Create pkg/workflow/expression_syntax_validation.go containing only the syntax-level helper functions:

• validateBalancedBraces
• validateExpressionSyntax
• validateExpressionContent
• validateBalancedQuotes

Step 2: Create pkg/workflow/runtime_import_validation.go containing:

• extractRuntimeImportPaths
• validateRuntimeImportFiles

Step 3: Rename/reduce expression_validation.go to expression_safety_validation.go (or keep the name) and remove functions moved to new files. Rename the remaining file to contain:

• validateExpressionSafety
• validateExpressionForDangerousProps
• validateSingleExpression
• containsExpression
• containsLogicalOperators

Step 4: Fix all imports in each new file (add/remove as needed).

Step 5: Run make fmt && make lint && make test-unit — all must pass.

⚠️ Do NOT change any function logic. This is a pure code reorganization refactor.

Files to Modify

• Split: pkg/workflow/expression_validation.go
• Create: pkg/workflow/expression_syntax_validation.go
• Create: pkg/workflow/runtime_import_validation.go
• Rename/update: pkg/workflow/expression_safety_validation.go (or keep original name reduced)

Acceptance Criteria

• expression_safety_validation.go contains orchestration and allowlist safety checks
• expression_syntax_validation.go contains syntax-level helpers
• runtime_import_validation.go contains import path logic
• All three files are under 300 lines
• make test-unit passes after the split
• make fmt && make lint pass

Generated by Plan Command for issue #discussion #21398 · ◷

• expires on Mar 19, 2026, 11:46 PM UTC