Duplicate Code: repoPolicyCheck updatePackageJsonFile resolver boilerplate

Analysis of commit 688c05dd39779ee023a5bb8fed97d59b64b4e6e2

Assignee: @copilot

Summary

Multiple repoPolicyCheck rules duplicate the same resolver boilerplate pattern: create a { resolved, message? } result, call updatePackageJsonFile(path.dirname(file), (json) => { ... }), sometimes mutate result on errors, then return result.

This repetition appears several times within npmPackages.ts and again in fluidBuildTasks.ts. It’s a maintainability smell: future adjustments to resolver behavior (error handling, logging, dry-run semantics, etc.) require updating many near-identical blocks.

Duplication Details

Pattern: “resolver wrapper around updatePackageJsonFile”

• Severity: Medium
• Occurrences: 7 (6 in npmPackages.ts, 1 in fluidBuildTasks.ts)
• Locations:
  • build-tools/packages/build-cli/src/library/repoPolicyCheck/npmPackages.ts
    • lines 840–863 (simple updatePackageJsonFile(...) then return { resolved: true })
    • lines 1122–1160 (similar structure)
    • lines 1292–1303 (const result ... updatePackageJsonFile ... return result)
    • lines 1586–1604 (const result ... updatePackageJsonFile ... return result)
    • lines 1723–1737 (const result ... updatePackageJsonFile ... return result)
    • lines 1919–1965 (const result ... updatePackageJsonFile ... return result)
  • build-tools/packages/build-cli/src/library/repoPolicyCheck/fluidBuildTasks.ts
    • lines 904–939 (let result ... updatePackageJsonFile ... return result)

Code Sample (excerpt)

From npmPackages.ts (around 1722):

resolver: (file: string): { resolved: boolean; message?: string } => {
	const result: { resolved: boolean; message?: string } = { resolved: true };
	updatePackageJsonFile(path.dirname(file), (json) => {
		if (shouldCheckExportsField(json)) {
			try {
				const exportsField = generateExportsField(json);
				json.exports = exportsField;
			} catch (error: unknown) {
				result.resolved = false;
				result.message = (error as Error).message;
			}
		}
	});
	return result;
}

From fluidBuildTasks.ts (around 904):

resolver: (file: string, root: string): { resolved: boolean; message?: string } => {
	let result: { resolved: boolean; message?: string } = { resolved: true };
	updatePackageJsonFile(path.dirname(file), (json) => {
		// ...
		try {
			// compute/patch deps
		} catch (error: unknown) {
			result = { resolved: false, message: (error as Error).message };
			return;
		}
	});
	return result;
}

Impact Analysis

• Maintainability: Resolver behavior is spread across many copies; refactors require repetitive edits and risk inconsistency.
• Bug Risk: Small differences in copied patterns (e.g., whether errors are caught, whether result is reassigned vs mutated) can lead to inconsistent outcomes.
• Code Bloat: The repeated scaffolding obscures the actual policy-specific logic.

Refactoring Recommendations

1. Extract a shared resolver helper

   • Suggested location: build-tools/packages/build-cli/src/library/repoPolicyCheck/common.ts
   • Example shape:
     • makeUpdatePackageJsonResolver((packageJson, ctx) => void, { onError?: ... })
     • or runUpdatePackageJsonResolver(fileOrDir, (json) => { ... }) => { resolved, message? }
   • Benefits: centralizes result creation, consistent error handling, and optionally supports async variants.

2. Normalize error handling semantics

   • Decide whether resolver callbacks should throw (and be caught centrally) or mutate a result object.
   • Benefits: fewer subtle differences, easier to test.

Implementation Checklist

• Identify all updatePackageJsonFile(...) resolver call sites under repoPolicyCheck/
• Add shared helper API in common.ts
• Refactor the duplicated resolvers to use the helper
• Ensure resolver return types and messages remain identical
• Run existing policy-check tests/commands to validate behavior

Analysis Metadata

• Analyzed Files: Top-churn + targeted cross-reference in build-tools/packages/build-cli/src/library/repoPolicyCheck/ and server/routerlicious/
• Detection Method: Serena semantic symbol search + pattern search
• Commit: 688c05dd39779ee023a5bb8fed97d59b64b4e6e2
• Analysis Date: 2026-04-01T21:51:29.453Z

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