Circular declarations cause infinite loops in getExportInfos since v5.5

[simon-paris]

🔎 Search Terms

infinite loop, circular, infinite loop, getExportInfos, invalid array length

🕗 Version & Regression Information

• This is an infinite loop in tsserver, eventually leading to a crash due to creating an infinitely sized array.
• This changed between versions 5.5.0-dev.20240508 and 5.5.0-dev.20240509
• Probably this pr: Refactor default export info name gathering #58460

⏯ Playground Link

Does not reproduce on playground

💻 Code

In an empty folder, place this code in types.d.ts

declare module "mymod" {
 import mymod from "mymod";
 export default mymod;
}

In another file index.ts, trigger an autocomplete or getCodeFixes. Typing two characters into an empty file will usually work. It will hang.

🙁 Actual behavior

The LSP server go into an infinite loop and hangs. After about 20 seconds it'll throw because an array gets too big.

The server log contains:

 RangeError: Invalid array length
 at Array.push (<anonymous>)
 at append (/Users/myusername/mweb/node_modules/typescript/lib/typescript.js:2822:6)
 at forEachNameOfDefaultExport (/Users/myusername/mweb/node_modules/typescript/lib/typescript.js:138888:13)
 at /Users/myusername/mweb/node_modules/typescript/lib/typescript.js:155493:115
 at /Users/myusername/mweb/node_modules/typescript/lib/typescript.js:138720:119
 at forEachExternalModule (/Users/myusername/mweb/node_modules/typescript/lib/typescript.js:138763:7)
 at forEachExternalModuleToImportFrom (/Users/myusername/mweb/node_modules/typescript/lib/typescript.js:138720:3)
 at getExportInfos (/Users/myusername/mweb/node_modules/typescript/lib/typescript.js:155488:3)
 at /Users/myusername/mweb/node_modules/typescript/lib/typescript.js:155424:24
 at flatMap (/Users/myusername/mweb/node_modules/typescript/lib/typescript.js:2502:17)
 at getFixesInfoForNonUMDImport (/Users/myusername/mweb/node_modules/typescript/lib/typescript.js:155418:10)
 at getFixInfos (/Users/myusername/mweb/node_modules/typescript/lib/typescript.js:155254:12)
 at Object.getCodeActions (/Users/myusername/mweb/node_modules/typescript/lib/typescript.js:154389:18)
 at /Users/myusername/mweb/node_modules/typescript/lib/typescript.js:151448:46
 at flatMap (/Users/myusername/mweb/node_modules/typescript/lib/typescript.js:2502:17)
 at Object.getFixes (/Users/myusername/mweb/node_modules/typescript/lib/typescript.js:151448:10)
 at /Users/myusername/mweb/node_modules/typescript/lib/typescript.js:149730:33
 at flatMap (/Users/myusername/mweb/node_modules/typescript/lib/typescript.js:2502:17)
 at Object.getCodeFixesAtPosition (/Users/myusername/mweb/node_modules/typescript/lib/typescript.js:149728:12)
 at IpcIOSession.getCodeFixes (/Users/myusername/mweb/node_modules/typescript/lib/typescript.js:191339:50)
 at getCodeFixes (/Users/myusername/mweb/node_modules/typescript/lib/typescript.js:189374:43)
 at /Users/myusername/mweb/node_modules/typescript/lib/typescript.js:191661:15
 at IpcIOSession.executeWithRequestId (/Users/myusername/mweb/node_modules/typescript/lib/typescript.js:191650:14)
 at IpcIOSession.executeCommand (/Users/myusername/mweb/node_modules/typescript/lib/typescript.js:191659:29)
 at IpcIOSession.onMessage (/Users/myusername/mweb/node_modules/typescript/lib/typescript.js:191707:68)
 at process.<anonymous> (/Users/myusername/mweb/node_modules/typescript/lib/tsserver.js:525:14)
 at process.emit (node:events:514:28)
 at emit (node:internal/child_process:951:14)
 at process.processTicksAndRejections (node:internal/process/task_queues:83:21)

🙂 Expected behavior

Nothing should happen.

Additional information about the issue

No response

[Andarist]

Cc Andrew Branch (@andrewbranch)

[andrewbranch]

declare module "mymod" {
 import mymod from "mymod";
 export default mymod;
}

What is this supposed to mean?

[simon-paris]

What is this supposed to mean?

It's nonsense from a dev who was new to typescript, a long time ago. I'm just reporting it anyways because its a crash.

[andrewbranch]

Makes sense, I was just wondering if this was a simplification of something found in a library.