[dexhunter]

TL;DR

• This PR makes coerce_input_literal faster. This function coerces literal arguments such as multiplier: 2 during execution.
• It unwraps NonNull in place and uses direct isinstance checks instead of the is_*_type helpers.
• The execution-arguments benchmark goes from 300.24 ms to 287.30 ms (4.3% faster, median of 3 runs).
• The full test suite passes: 3625 passed, 18 skipped, the same as on main.

Refs #302

What & Why

Before, a NonNull type made the function call itself with the inner type. That second call checked the variable node and the null literal again. Each type check also went through an is_*_type helper, which is one more function call around isinstance.

Now the function checks for a null literal once. Then it replaces type_ with type_.of_type and continues in the same call. It checks GraphQLNonNull, GraphQLList and GraphQLInputObjectType directly. The list and object loops keep append and get in local names. The object branch reads each field value node once. Leaf types still go through assert_leaf_type. The branches return the same values in the same order, so every result stays identical.

graphql-js uses recursion for NonNull in coerceInputLiteral. This PR changes that on purpose, because a Python function call costs much more than a JavaScript call.

Results

Time per call, median of 3 runs on Python 3.12:

Situation	Before	After	Change
Int! literal (multiplier: 2)	734 ns	479 ns	35% faster
[Int!] list of 10 ints	7557 ns	5089 ns	33% faster
input object {a: 1, b: "x"}	2355 ns	1717 ns	27% faster
variable $v (code path not changed)	172 ns	156 ns	no real change (runs vary from 156 to 193 ns)
execute_sync of the 1000-item query from test_execution_arguments.py	5.32 ms	5.00 ms	6% faster

Why this is safe and easy to maintain

The change is small and stays inside one function. It uses the same isinstance checks that the is_*_type helpers use, so behaviour and output do not change. The existing tests in tests/utilities/test_coerce_input_value.py, tests/execution and the module doctests cover all branches.

Validation

• Tests: pytest tests gives 3625 passed, 18 skipped, with and without this change. mypy and ruff check/ruff format --check pass on the changed file.
• Benchmark: a workload with the 1000-item query from tests/benchmarks/test_execution_arguments.py plus 336 mixed literal cases. It runs in 300.24 ms before and 287.30 ms after (median of 3 runs, each 11 alternating before/after pairs).
• Quick check with the repository benchmark: pytest tests/benchmarks/test_execution_arguments.py --benchmark-only

I did not add new tests because behaviour does not change.

AI assistance

Candidate changes came from Codex (gpt-6.1-sol), and Weco Observe tracked them. Claude Code picked this candidate, checked it with the test suite, mypy and ruff, and measured it. A person did not review the change before submission.

Weco share link: https://dashboard.weco.ai/share/z3O_QHq3doOpQrFvfclgdtSNB6ioeuCH

[codspeed]

Merging this PR will not alter performance

✅ 20 untouched benchmarks

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_{Comparing dexhunter:perf/coerce-input-literal-direct-type-checks (c0bb1a4) with main (1d505c1)}