fix(codegen): argless builtins ignore extra args instead of bailing

[proggeramlug]

What

Argless built-in methods (String.prototype trim/trimStart/trimEnd/toLowerCase/toUpperCase/isWellFormed/toWellFormed, Array.prototype pop/shift) bail!ed in codegen when called with extra args. But per ECMA-262 those args are simply ignored ("x".trim(1) is legal and returns the trimmed string). Minified bundles do this. Now codegen evaluates the surplus args for side effects (spec requires arg evaluation) and discards them, matching the Annex-B HTML-wrapper convention already in the same file, instead of failing the compile.

Why

Surfaced compiling a large real-world minified bundle: perry-codegen: String.trim takes no args, got 1 aborted the whole module.

Tests

New crates/perry-codegen/tests/argless_builtin_extra_args.rs (" x ".trim(1) → js_string_trim; [1].pop(99) compiles). cargo test -p perry-codegen --tests green.

Summary by CodeRabbit

• Bug Fixes

  • Updated lowering for array pop and shift and string methods toLowerCase, toUpperCase, trim, trimStart, trimEnd, and isWellFormed to ignore extra arguments while still evaluating them for side effects, matching JavaScript behavior.

• Tests

  • Added a regression test covering argless builtin method calls with extra arguments, including verification of the expected lowering.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro Plus

Run ID: 54fb6c52-3bc7-4e2f-a87c-9a9e17d58a1a

📥 Commits

Reviewing files that changed from the base of the PR and between bf4dbfc and 69bcb0e.

📒 Files selected for processing (3)

• crates/perry-codegen/src/lower_array_method.rs
• crates/perry-codegen/src/lower_string_method.rs
• crates/perry-codegen/tests/argless_builtin_extra_args.rs

🚧 Files skipped from review as they are similar to previous changes (3)

• crates/perry-codegen/tests/argless_builtin_extra_args.rs
• crates/perry-codegen/src/lower_array_method.rs
• crates/perry-codegen/src/lower_string_method.rs

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📝 Walkthrough

Walkthrough

Argless builtin method lowering arms for Array.pop, Array.shift, string case/trim methods, and String.isWellFormed no longer error when callers pass extra arguments. The bail! checks are replaced with side-effect-preserving evaluation loops that discard the results. A new regression test file validates this behavior for String.trim and Array.pop.

Changes

Argless Builtin Extra-Arg Tolerance

Layer / File(s)	Summary
Array method lowering: pop and shift crates/perry-codegen/src/lower_array_method.rs	pop and shift arms remove their bail! argument-count checks and instead iterate over extra args, calling lower_expr for each to preserve side effects before invoking the existing no-arg runtime helper.
String method lowering: unary and isWellFormed crates/perry-codegen/src/lower_string_method.rs	Unary string-returning methods (toLowerCase, toUpperCase, trim, trimStart, trimEnd) and isWellFormed drop their bail! argument-count checks and instead iterate over extra args, calling lower_expr for each to preserve side effects before invoking the runtime helper.
Regression tests for extra-arg tolerance crates/perry-codegen/tests/argless_builtin_extra_args.rs	New test file adds empty_opts() and module_with_init() helpers, plus two unit tests that compile String.trim and Array.pop calls with a surplus numeric argument, asserting compilation succeeds and verifying the expected runtime helper appears in the output IR.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

Possibly related issues

• codegen: user method named like a String builtin (internals.trim(value, schema)) mis-lowered to String.prototype.<m> on non-string receivers — joi #5271: The extra-argument validation errors on argless builtins (e.g., String.trim receiving unexpected args) are directly addressed by the bail! removal in this PR.

Possibly related PRs

• PerryTS/perry#5272: Complements this PR by adding an arity-aware gate in the String-method fast-path dispatch to prevent mis-dispatch on non-string receivers, while this PR handles the argument evaluation semantics for argless methods themselves.

Poem

🐇 Hop hop, no more bail!
Extra args? We'll just flail
through lower_expr once or twice,
toss the results—oh how nice.
Side effects kept, errors gone,
the trim still trims—carry on! ✂️

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly and concisely summarizes the main change: fixing argless builtins to ignore extra arguments instead of failing compilation.
Description check	✅ Passed	The PR description covers the what, why, and tests sections with clear explanations. However, the required checklist section is missing/incomplete, which is a non-critical omission given the substantial content provided.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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✨ Finishing Touches

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• Create PR with unit tests
• Commit unit tests in branch fix/codegen-argless-builtin-args

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[coderabbitai]

🧹 Nitpick comments (1)

crates/perry-codegen/tests/argless_builtin_extra_args.rs (1)

91-129: ⚡ Quick win

Expand regression coverage to all modified argless arms.

This file currently verifies only trim and pop, while the PR also changes shift, toLowerCase/toUpperCase/trimStart/trimEnd, isWellFormed, and toWellFormed. Adding one compile-success case per method family here would better lock the behavior and prevent partial regressions.

🤖 Prompt for AI Agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In `@crates/perry-codegen/tests/argless_builtin_extra_args.rs` around lines 91 -
129, The test file currently only verifies compile-success cases for the argless
methods trim and pop, but the PR modifies several other argless methods
including shift, toLowerCase, toUpperCase, trimStart, trimEnd, isWellFormed, and
toWellFormed. Add a new test function for each of these remaining modified
argless methods following the same pattern as
string_trim_with_extra_arg_compiles and array_pop_with_extra_arg_compiles—create
an AST that calls each method with an extra argument, compile it, and assert
that compilation succeeds. This ensures regression coverage for all modified
argless arms and prevents partial regressions if only some of them are properly
handled.

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Nitpick comments:
In `@crates/perry-codegen/tests/argless_builtin_extra_args.rs`:
- Around line 91-129: The test file currently only verifies compile-success
cases for the argless methods trim and pop, but the PR modifies several other
argless methods including shift, toLowerCase, toUpperCase, trimStart, trimEnd,
isWellFormed, and toWellFormed. Add a new test function for each of these
remaining modified argless methods following the same pattern as
string_trim_with_extra_arg_compiles and array_pop_with_extra_arg_compiles—create
an AST that calls each method with an extra argument, compile it, and assert
that compilation succeeds. This ensures regression coverage for all modified
argless arms and prevents partial regressions if only some of them are properly
handled.

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ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro Plus

Run ID: 084df4d3-60e9-4b42-9f2e-caa74338de01

📥 Commits

Reviewing files that changed from the base of the PR and between d46feff and bf4dbfc.

📒 Files selected for processing (3)

• crates/perry-codegen/src/lower_array_method.rs
• crates/perry-codegen/src/lower_string_method.rs
• crates/perry-codegen/tests/argless_builtin_extra_args.rs