[js_repl] Support local ESM file imports (#13437)

## Summary
- add `js_repl` support for dynamic imports of relative and absolute
local ESM `.js` / `.mjs` files
- keep bare package imports on the native Node path and resolved from
REPL-global search roots (`CODEX_JS_REPL_NODE_MODULE_DIRS`, then `cwd`),
even when they originate from imported local files
- restrict static imports inside imported local files to other local
relative/absolute `.js` / `.mjs` files, and surface a clear error for
unsupported top-level static imports in the REPL cell
- run imported local files inside the REPL VM context so they can access
`codex.tmpDir`, `codex.tool`, captured `console`, and Node-like
`import.meta` helpers
- reload local files between execs so later `await import("./file.js")`
calls pick up edits and fixed failures, while preserving package/builtin
caching and persistent top-level REPL bindings
- make `import.meta.resolve()` self-consistent by allowing the returned
`file://...` URLs to round-trip through `await import(...)`
- update both public and injected `js_repl` docs to clarify the narrowed
contract, including global bare-import resolution behavior for local
absolute files

## Testing
- `cargo test -p codex-core js_repl_`
- built codex binary and verified behavior

---------

Co-authored-by: Codex <noreply@openai.com>

codex-rs/core/src/project_doc.rs

@@ -65,7 +65,7 @@ fn render_js_repl_instructions(config: &Config) -> Option<String> {
         section.push_str("- When generating or converting images for `view_image` in `js_repl`, prefer JPEG at 85% quality unless lossless quality is strictly required; other formats can be used if the user requests them. This keeps uploads smaller and reduces the chance of hitting image size caps.\n");
     }
     section.push_str("- Top-level bindings persist across cells. If you hit `SyntaxError: Identifier 'x' has already been declared`, reuse the binding, pick a new name, wrap in `{ ... }` for block scope, or reset the kernel with `js_repl_reset`.\n");
-    section.push_str("- Top-level static import declarations (for example `import x from \"pkg\"`) are currently unsupported in `js_repl`; use dynamic imports with `await import(\"pkg\")` instead.\n");
+    section.push_str("- Top-level static import declarations (for example `import x from \"./file.js\"`) are currently unsupported in `js_repl`; use dynamic imports with `await import(\"pkg\")`, `await import(\"./file.js\")`, or `await import(\"/abs/path/file.mjs\")` instead. Imported local files must be ESM `.js`/`.mjs` files and run in the same REPL VM context. Bare package imports always resolve from REPL-global search roots (`CODEX_JS_REPL_NODE_MODULE_DIRS`, then cwd), not relative to the imported file location. Local files may statically import only other local relative/absolute/`file://` `.js`/`.mjs` files; package and builtin imports from local files must stay dynamic. `import.meta.resolve()` returns importable strings such as `file://...`, bare package names, and `node:...` specifiers. Local file modules reload between execs, while top-level bindings persist until `js_repl_reset`.\n");
 
     if config.features.enabled(Feature::JsReplToolsOnly) {
         section.push_str("- Do not call tools directly; use `js_repl` + `codex.tool(...)` for all tool calls, including shell commands.\n");
@@ -492,7 +492,7 @@ mod tests {
         let res = get_user_instructions(&cfg, None, None)
             .await
             .expect("js_repl instructions expected");
-        let expected = "## JavaScript REPL (Node)\n- Use `js_repl` for Node-backed JavaScript with top-level await in a persistent kernel.\n- `js_repl` is a freeform/custom tool. Direct `js_repl` calls must send raw JavaScript tool input (optionally with first-line `// codex-js-repl: timeout_ms=15000`). Do not wrap code in JSON (for example `{\"code\":\"...\"}`), quotes, or markdown code fences.\n- Helpers: `codex.tmpDir`, `codex.tool(name, args?)`, and `codex.emitImage(imageLike)`.\n- `codex.tool` executes a normal tool call and resolves to the raw tool output object. Use it for shell and non-shell tools alike. Nested tool outputs stay inside JavaScript unless you emit them explicitly.\n- `codex.emitImage(...)` adds exactly one image to the outer `js_repl` function output. It accepts a direct image URL, a single `input_image` item, an object like `{ bytes, mimeType }`, or a raw tool response object with exactly one image and no text. It rejects mixed text-and-image content.\n- Example of sharing an in-memory Playwright screenshot: `await codex.emitImage({ bytes: await page.screenshot({ type: \"jpeg\", quality: 85 }), mimeType: \"image/jpeg\" })`.\n- Example of sharing a local image tool result: `await codex.emitImage(codex.tool(\"view_image\", { path: \"/absolute/path\" }))`.\n- Top-level bindings persist across cells. If you hit `SyntaxError: Identifier 'x' has already been declared`, reuse the binding, pick a new name, wrap in `{ ... }` for block scope, or reset the kernel with `js_repl_reset`.\n- Top-level static import declarations (for example `import x from \"pkg\"`) are currently unsupported in `js_repl`; use dynamic imports with `await import(\"pkg\")` instead.\n- Avoid direct access to `process.stdout` / `process.stderr` / `process.stdin`; it can corrupt the JSON line protocol. Use `console.log`, `codex.tool(...)`, and `codex.emitImage(...)`.";
+        let expected = "## JavaScript REPL (Node)\n- Use `js_repl` for Node-backed JavaScript with top-level await in a persistent kernel.\n- `js_repl` is a freeform/custom tool. Direct `js_repl` calls must send raw JavaScript tool input (optionally with first-line `// codex-js-repl: timeout_ms=15000`). Do not wrap code in JSON (for example `{\"code\":\"...\"}`), quotes, or markdown code fences.\n- Helpers: `codex.tmpDir`, `codex.tool(name, args?)`, and `codex.emitImage(imageLike)`.\n- `codex.tool` executes a normal tool call and resolves to the raw tool output object. Use it for shell and non-shell tools alike. Nested tool outputs stay inside JavaScript unless you emit them explicitly.\n- `codex.emitImage(...)` adds exactly one image to the outer `js_repl` function output. It accepts a direct image URL, a single `input_image` item, an object like `{ bytes, mimeType }`, or a raw tool response object with exactly one image and no text. It rejects mixed text-and-image content.\n- Example of sharing an in-memory Playwright screenshot: `await codex.emitImage({ bytes: await page.screenshot({ type: \"jpeg\", quality: 85 }), mimeType: \"image/jpeg\" })`.\n- Example of sharing a local image tool result: `await codex.emitImage(codex.tool(\"view_image\", { path: \"/absolute/path\" }))`.\n- Top-level bindings persist across cells. If you hit `SyntaxError: Identifier 'x' has already been declared`, reuse the binding, pick a new name, wrap in `{ ... }` for block scope, or reset the kernel with `js_repl_reset`.\n- Top-level static import declarations (for example `import x from \"./file.js\"`) are currently unsupported in `js_repl`; use dynamic imports with `await import(\"pkg\")`, `await import(\"./file.js\")`, or `await import(\"/abs/path/file.mjs\")` instead. Imported local files must be ESM `.js`/`.mjs` files and run in the same REPL VM context. Bare package imports always resolve from REPL-global search roots (`CODEX_JS_REPL_NODE_MODULE_DIRS`, then cwd), not relative to the imported file location. Local files may statically import only other local relative/absolute/`file://` `.js`/`.mjs` files; package and builtin imports from local files must stay dynamic. `import.meta.resolve()` returns importable strings such as `file://...`, bare package names, and `node:...` specifiers. Local file modules reload between execs, while top-level bindings persist until `js_repl_reset`.\n- Avoid direct access to `process.stdout` / `process.stderr` / `process.stdin`; it can corrupt the JSON line protocol. Use `console.log`, `codex.tool(...)`, and `codex.emitImage(...)`.";
         assert_eq!(res, expected);
     }
 
@@ -511,7 +511,7 @@ mod tests {
         let res = get_user_instructions(&cfg, None, None)
             .await
             .expect("js_repl instructions expected");
-        let expected = "## JavaScript REPL (Node)\n- Use `js_repl` for Node-backed JavaScript with top-level await in a persistent kernel.\n- `js_repl` is a freeform/custom tool. Direct `js_repl` calls must send raw JavaScript tool input (optionally with first-line `// codex-js-repl: timeout_ms=15000`). Do not wrap code in JSON (for example `{\"code\":\"...\"}`), quotes, or markdown code fences.\n- Helpers: `codex.tmpDir`, `codex.tool(name, args?)`, and `codex.emitImage(imageLike)`.\n- `codex.tool` executes a normal tool call and resolves to the raw tool output object. Use it for shell and non-shell tools alike. Nested tool outputs stay inside JavaScript unless you emit them explicitly.\n- `codex.emitImage(...)` adds exactly one image to the outer `js_repl` function output. It accepts a direct image URL, a single `input_image` item, an object like `{ bytes, mimeType }`, or a raw tool response object with exactly one image and no text. It rejects mixed text-and-image content.\n- Example of sharing an in-memory Playwright screenshot: `await codex.emitImage({ bytes: await page.screenshot({ type: \"jpeg\", quality: 85 }), mimeType: \"image/jpeg\" })`.\n- Example of sharing a local image tool result: `await codex.emitImage(codex.tool(\"view_image\", { path: \"/absolute/path\" }))`.\n- Top-level bindings persist across cells. If you hit `SyntaxError: Identifier 'x' has already been declared`, reuse the binding, pick a new name, wrap in `{ ... }` for block scope, or reset the kernel with `js_repl_reset`.\n- Top-level static import declarations (for example `import x from \"pkg\"`) are currently unsupported in `js_repl`; use dynamic imports with `await import(\"pkg\")` instead.\n- Do not call tools directly; use `js_repl` + `codex.tool(...)` for all tool calls, including shell commands.\n- MCP tools (if any) can also be called by name via `codex.tool(...)`.\n- Avoid direct access to `process.stdout` / `process.stderr` / `process.stdin`; it can corrupt the JSON line protocol. Use `console.log`, `codex.tool(...)`, and `codex.emitImage(...)`.";
+        let expected = "## JavaScript REPL (Node)\n- Use `js_repl` for Node-backed JavaScript with top-level await in a persistent kernel.\n- `js_repl` is a freeform/custom tool. Direct `js_repl` calls must send raw JavaScript tool input (optionally with first-line `// codex-js-repl: timeout_ms=15000`). Do not wrap code in JSON (for example `{\"code\":\"...\"}`), quotes, or markdown code fences.\n- Helpers: `codex.tmpDir`, `codex.tool(name, args?)`, and `codex.emitImage(imageLike)`.\n- `codex.tool` executes a normal tool call and resolves to the raw tool output object. Use it for shell and non-shell tools alike. Nested tool outputs stay inside JavaScript unless you emit them explicitly.\n- `codex.emitImage(...)` adds exactly one image to the outer `js_repl` function output. It accepts a direct image URL, a single `input_image` item, an object like `{ bytes, mimeType }`, or a raw tool response object with exactly one image and no text. It rejects mixed text-and-image content.\n- Example of sharing an in-memory Playwright screenshot: `await codex.emitImage({ bytes: await page.screenshot({ type: \"jpeg\", quality: 85 }), mimeType: \"image/jpeg\" })`.\n- Example of sharing a local image tool result: `await codex.emitImage(codex.tool(\"view_image\", { path: \"/absolute/path\" }))`.\n- Top-level bindings persist across cells. If you hit `SyntaxError: Identifier 'x' has already been declared`, reuse the binding, pick a new name, wrap in `{ ... }` for block scope, or reset the kernel with `js_repl_reset`.\n- Top-level static import declarations (for example `import x from \"./file.js\"`) are currently unsupported in `js_repl`; use dynamic imports with `await import(\"pkg\")`, `await import(\"./file.js\")`, or `await import(\"/abs/path/file.mjs\")` instead. Imported local files must be ESM `.js`/`.mjs` files and run in the same REPL VM context. Bare package imports always resolve from REPL-global search roots (`CODEX_JS_REPL_NODE_MODULE_DIRS`, then cwd), not relative to the imported file location. Local files may statically import only other local relative/absolute/`file://` `.js`/`.mjs` files; package and builtin imports from local files must stay dynamic. `import.meta.resolve()` returns importable strings such as `file://...`, bare package names, and `node:...` specifiers. Local file modules reload between execs, while top-level bindings persist until `js_repl_reset`.\n- Do not call tools directly; use `js_repl` + `codex.tool(...)` for all tool calls, including shell commands.\n- MCP tools (if any) can also be called by name via `codex.tool(...)`.\n- Avoid direct access to `process.stdout` / `process.stderr` / `process.stdin`; it can corrupt the JSON line protocol. Use `console.log`, `codex.tool(...)`, and `codex.emitImage(...)`.";
         assert_eq!(res, expected);
     }
 
@@ -530,7 +530,7 @@ mod tests {
         let res = get_user_instructions(&cfg, None, None)
             .await
             .expect("js_repl instructions expected");
-        let expected = "## JavaScript REPL (Node)\n- Use `js_repl` for Node-backed JavaScript with top-level await in a persistent kernel.\n- `js_repl` is a freeform/custom tool. Direct `js_repl` calls must send raw JavaScript tool input (optionally with first-line `// codex-js-repl: timeout_ms=15000`). Do not wrap code in JSON (for example `{\"code\":\"...\"}`), quotes, or markdown code fences.\n- Helpers: `codex.tmpDir`, `codex.tool(name, args?)`, and `codex.emitImage(imageLike)`.\n- `codex.tool` executes a normal tool call and resolves to the raw tool output object. Use it for shell and non-shell tools alike. Nested tool outputs stay inside JavaScript unless you emit them explicitly.\n- `codex.emitImage(...)` adds exactly one image to the outer `js_repl` function output. It accepts a direct image URL, a single `input_image` item, an object like `{ bytes, mimeType }`, or a raw tool response object with exactly one image and no text. It rejects mixed text-and-image content.\n- Example of sharing an in-memory Playwright screenshot: `await codex.emitImage({ bytes: await page.screenshot({ type: \"jpeg\", quality: 85 }), mimeType: \"image/jpeg\" })`.\n- Example of sharing a local image tool result: `await codex.emitImage(codex.tool(\"view_image\", { path: \"/absolute/path\" }))`.\n- When generating or converting images for `view_image` in `js_repl`, prefer JPEG at 85% quality unless lossless quality is strictly required; other formats can be used if the user requests them. This keeps uploads smaller and reduces the chance of hitting image size caps.\n- Top-level bindings persist across cells. If you hit `SyntaxError: Identifier 'x' has already been declared`, reuse the binding, pick a new name, wrap in `{ ... }` for block scope, or reset the kernel with `js_repl_reset`.\n- Top-level static import declarations (for example `import x from \"pkg\"`) are currently unsupported in `js_repl`; use dynamic imports with `await import(\"pkg\")` instead.\n- Avoid direct access to `process.stdout` / `process.stderr` / `process.stdin`; it can corrupt the JSON line protocol. Use `console.log`, `codex.tool(...)`, and `codex.emitImage(...)`.";
+        let expected = "## JavaScript REPL (Node)\n- Use `js_repl` for Node-backed JavaScript with top-level await in a persistent kernel.\n- `js_repl` is a freeform/custom tool. Direct `js_repl` calls must send raw JavaScript tool input (optionally with first-line `// codex-js-repl: timeout_ms=15000`). Do not wrap code in JSON (for example `{\"code\":\"...\"}`), quotes, or markdown code fences.\n- Helpers: `codex.tmpDir`, `codex.tool(name, args?)`, and `codex.emitImage(imageLike)`.\n- `codex.tool` executes a normal tool call and resolves to the raw tool output object. Use it for shell and non-shell tools alike. Nested tool outputs stay inside JavaScript unless you emit them explicitly.\n- `codex.emitImage(...)` adds exactly one image to the outer `js_repl` function output. It accepts a direct image URL, a single `input_image` item, an object like `{ bytes, mimeType }`, or a raw tool response object with exactly one image and no text. It rejects mixed text-and-image content.\n- Example of sharing an in-memory Playwright screenshot: `await codex.emitImage({ bytes: await page.screenshot({ type: \"jpeg\", quality: 85 }), mimeType: \"image/jpeg\" })`.\n- Example of sharing a local image tool result: `await codex.emitImage(codex.tool(\"view_image\", { path: \"/absolute/path\" }))`.\n- When generating or converting images for `view_image` in `js_repl`, prefer JPEG at 85% quality unless lossless quality is strictly required; other formats can be used if the user requests them. This keeps uploads smaller and reduces the chance of hitting image size caps.\n- Top-level bindings persist across cells. If you hit `SyntaxError: Identifier 'x' has already been declared`, reuse the binding, pick a new name, wrap in `{ ... }` for block scope, or reset the kernel with `js_repl_reset`.\n- Top-level static import declarations (for example `import x from \"./file.js\"`) are currently unsupported in `js_repl`; use dynamic imports with `await import(\"pkg\")`, `await import(\"./file.js\")`, or `await import(\"/abs/path/file.mjs\")` instead. Imported local files must be ESM `.js`/`.mjs` files and run in the same REPL VM context. Bare package imports always resolve from REPL-global search roots (`CODEX_JS_REPL_NODE_MODULE_DIRS`, then cwd), not relative to the imported file location. Local files may statically import only other local relative/absolute/`file://` `.js`/`.mjs` files; package and builtin imports from local files must stay dynamic. `import.meta.resolve()` returns importable strings such as `file://...`, bare package names, and `node:...` specifiers. Local file modules reload between execs, while top-level bindings persist until `js_repl_reset`.\n- Avoid direct access to `process.stdout` / `process.stderr` / `process.stdin`; it can corrupt the JSON line protocol. Use `console.log`, `codex.tool(...)`, and `codex.emitImage(...)`.";
         assert_eq!(res, expected);
     }