René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Setting `\"experimental-test-coverage\": true` within node.config.json causes multiple reports","articleBody":"### Version\n\n24.3.0\n\n### Platform\n\n```text\n\n```\n\n### Subsystem\n\n_No response_\n\n### What steps will reproduce the bug?\n\n1. Create a node.config.json file and include `\"experimental-test-coverage\": true`\n2. in CLI, run `node --experimental-config-file='./node.config.json' --test`\n\n### How often does it reproduce? Is there a required condition?\n\n100%\n\n### What is the expected behavior? Why is that the expected behavior?\n\nIt behaves like passing the CLI flag `--experimental-test-coverage`.\n\n### What do you see instead?\n\nIt appears the test coverage \"flag\" from the config file is getting passed along to the various sub-processes the test runner spawns, and they are each reporting their own set of tests' coverage. And then at the end, the parent process reports the full coverage.\n\n### Additional information\n\nMerely moving the test coverage flag from config file to cli (leaving other options in the config file) avoids the issue.\n\n\u003cdetails\u003e\n\u003csummary\u003enode.config.test.json\u003c/summary\u003e\n\n```json\n{\n  \"$schema\": \"https://nodejs.org/dist/v24.3.0/docs/node-config-schema.json\",\n  \"nodeOptions\": {\n    \"import\": [\n      \"../../test/snapshots.mts\"\n    ]\n  },\n  \"testRunner\": {\n    \"experimental-test-coverage\": true,\n    \"experimental-test-module-mocks\": true,\n    \"test-coverage-exclude\": [\n      \"**/test/**\",\n      \"**/*.mock.ts\",\n      \"**/*.test.ts\"\n    ]\n  }\n}\n```\n\u003c/details\u003e","author":{"url":"https://github.com/JakobJingleheimer","@type":"Person","name":"JakobJingleheimer"},"datePublished":"2025-06-25T09:13:02.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":3},"url":"https://github.com/58828/node/issues/58828"}