feat(cli): warn on unrecognized CLI options by sanjanaravikumar-az · Pull Request #1514 · aws/aws-cdk-cli

sanjanaravikumar-az · 2026-05-14T16:22:59Z

Summary

Adds a warning when unrecognized CLI options are passed, since yargs currently silently ignores them
Handles edge cases: env-injected keys (CDK_* via .env('CDK')), undefined defaults, camelCase variants, boolean negations, negativeAliases

This implements a non-breaking warning approach. Unrecognized options are still processed by yargs as before, but users now get feedback that their flag was not recognized.

Changes

File	Change
`check-unknown-options.ts`	New utility that detects unrecognized options
`cli.ts`	Calls `findUnknownOptions` and emits a warning
`check-unknown-options.test.ts`	10 tests covering all edge cases

Test plan

10 unit tests passing (known options, aliases, camelCase, negation, env-injected, unknown detection)

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license

🤖 Generated with Claude Code

Yargs does not enable strict option checking by default, so unknown flags are silently swallowed. This adds a warning when unrecognized options are detected, helping users catch typos early. Handles edge cases: - Skips undefined-value keys (yargs default placeholders from other commands) - Skips camelCase variants of known kebab-case options - Skips boolean negation keys (noFoo for --no-foo) - Skips negativeAlias keys (e.g. R for --no-rollback) - Skips keys injected by yargs .env('CDK') from CDK_* environment variables Closes #928 (partial — related to rix0rrr's strict parsing suggestion) Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

github-actions · 2026-05-14T16:23:12Z

Dependency Review

✅ No vulnerabilities or license issues or OpenSSF Scorecard issues found.

Scanned Files

None

codecov-commenter · 2026-05-14T16:46:07Z

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 88.22%. Comparing base (ae2349b) to head (9d21c60).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1514      +/-   ##
==========================================
+ Coverage   88.10%   88.22%   +0.12%     
==========================================
  Files          75       76       +1     
  Lines       10723    10816      +93     
  Branches     1465     1488      +23     
==========================================
+ Hits         9447     9542      +95     
+ Misses       1248     1246       -2     
  Partials       28       28

Flag	Coverage Δ
suite.unit	`88.22% <100.00%> (+0.12%)`	⬆️

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mrgrain · 2026-05-15T08:55:48Z

+    expect(findUnknownOptions(argv)).toEqual([]);
+  });
+
+  test('does not report keys injected by yargs .env("CDK") from environment variables', () => {


I dug into it and the test was actually wrong. I ran the actual CDK parser and yargs doesn't create noFoo keys from --no-foo flags, it just sets foo: false. The only way a noFoo key ends up in argv is if someone sets CDK_NO_FOO as an env var (via .env('CDK')), which the env prefix check already covers. Removed.

mrgrain · 2026-05-15T08:59:39Z

+ */
+export function findUnknownOptions(argv: any): string[] {
+  // eslint-disable-next-line @typescript-eslint/no-require-imports
+  const config = require('../cli-type-registry.json');


nit: this doesn't change, so can be outside the function as a "global" variable. In practice this doesn't matter much because findUnknownOptions is only called once and require is cached, but you should start to thinking about these kind of things.

The same applies to much of the "setup" code later on: sorting global and command options etc.

A good question to ask is: Which parts of the code are actually dependent on the argv input? Which parts only depend on the static cli-type-registry.json? This will give you an idea how to split it.

That's a good point, thank you! Moved the registry load and global options set to module scope since they never change. Only the command-specific options are computed inside the function now since those depend on which command was invoked.

mrgrain · 2026-05-15T09:03:05Z

+    if (argv[key] === undefined) continue;
+    if (yargsInternals.has(key)) continue;
+    if (globalOptions.has(key)) continue;
+    if (commandOptions.has(key)) continue;


can be one if

I actually removed this entirely since it's the same issue as the first comment. The negation check was solving a problem that doesn't exist with how yargs works.

mrgrain · 2026-05-15T09:03:51Z

+      if (globalOptions.has(positiveKey) || commandOptions.has(positiveKey) ||
+          globalOptions.has(positiveKebab) || commandOptions.has(positiveKebab)) continue;


we should enforce this as a linter rule, but imho these lines are hard to parse and read. Prefer always using {}.

got it, changed it

mrgrain · 2026-05-15T09:05:37Z

+function camelToKebab(str: string): string {
+  return str.replace(/[A-Z]/g, (m) => `-${m.toLowerCase()}`);
+}


This probably happens to work in this case, but is likely not working in the general case. For your code, it would be much easier to go the other way: From kebab to camel.

ah okay, switched it

mrgrain

small feedback.

- Move static config and global options set to module scope - Replace camelToKebab with kebabToCamel (applied at set-construction time) - Remove unnecessary isNegationOfKnownOption — verified that yargs does NOT create "noFoo" keys from --no-foo flags; the only noFoo keys come from CDK_NO_FOO env vars which isFromEnvPrefix already handles - Always use braces for if/continue statements - Combine the noFoo negation check into isFromEnvPrefix coverage - Add explanatory comment on env var test Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

sanjanaravikumar-az temporarily deployed to automation May 14, 2026 16:23 — with GitHub Actions Inactive

aws-cdk-automation requested a review from a team May 14, 2026 16:23

sanjanaravikumar-az temporarily deployed to no-approval May 14, 2026 16:23 — with GitHub Actions Inactive

github-actions Bot added the p2 label May 14, 2026

aws-cdk-automation enabled auto-merge May 14, 2026 16:23

sanjanaravikumar-az temporarily deployed to run-tests May 14, 2026 16:27 — with GitHub Actions Inactive

sanjanaravikumar-az temporarily deployed to run-tests May 14, 2026 16:44 — with GitHub Actions Inactive

Merge branch 'main' into sanjrkmr/warn-unknown-options

9326598

sanjanaravikumar-az temporarily deployed to no-approval May 14, 2026 17:08 — with GitHub Actions Inactive

sanjanaravikumar-az temporarily deployed to run-tests May 14, 2026 17:12 — with GitHub Actions Inactive

mrgrain reviewed May 15, 2026

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mrgrain requested changes May 15, 2026

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sanjanaravikumar-az and others added 2 commits May 15, 2026 12:54

Merge branch 'main' into sanjrkmr/warn-unknown-options

9d21c60

		if (globalOptions.has(positiveKey) \|\| commandOptions.has(positiveKey) \|\|
		globalOptions.has(positiveKebab) \|\| commandOptions.has(positiveKebab)) continue;

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sanjanaravikumar-az commented May 14, 2026 •

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mrgrain May 15, 2026 •

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