Playwright's babel transform hardcodes its own jsx-runtime as the importSource for all JSX, ignoring the user's tsconfig.json. This means JSX in test files always produces {__pw_type: 'jsx', ...} descriptor objects instead of real React elements, breaking any code that passes JSX to React APIs like renderToStaticMarkup().

Error: Objects are not valid as a React child (found: object with keys {__pw_type, type, props, key})

Changes

• tsconfig-loader.ts — Parse jsx and jsxImportSource from compilerOptions. When jsx is react-jsx/react-jsxdev with no explicit jsxImportSource, default to "react" (matching tsc behavior).
• transform.ts — Add jsxImportSourceForFile() to look up the configured JSX import source from tsconfig, include it in the compilation cache hash, and thread it through to babelTransform.
• babelBundle.ts — Extend BabelTransformFunction type with optional jsxImportSource.
• babelBundleImpl.ts — Use user's jsxImportSource when present, fall back to Playwright's own JSX runtime otherwise:

  importSource: jsxImportSource ? jsxImportSource : path.dirname(require.resolve('playwright')),

• loader.spec.ts — Two new tests: explicit jsxImportSource from tsconfig, and implicit defaulting via jsx: "react-jsx".
• BUG_DIAGNOSIS.md — Root cause analysis.

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