Fix auto-import of subpath imports starting with `#/` in supported module resolution modes by andrewbranch · Pull Request #3123 · microsoft/typescript-go

andrewbranch · 2026-03-17T16:17:08Z

Auto-imports was never updated to allow subpath imports starting with #/ after microsoft/TypeScript#62844 landed. Same as with module resolution, they're only considered valid in --moduleResolution nodenext and bundler.

Fixes #2984

…d streamline completion checks

Copilot

Pull request overview

This PR investigates #2984 (auto-import preferring deep relative paths over shorter package.json#imports root wildcard aliases) and applies a minimal fix so #/* mappings can contribute #/... module specifiers during auto-import generation.

Changes:

Add investigation notes documenting repro, root cause, and fix.
Update tryGetModuleNameFromPackageJsonImports to allow the #/* root wildcard imports key.
Add a focused fourslash test covering the #/* -> #/... auto-import preference for both shortest and non-relative.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.

File	Description
investigations/issue-2984-autoimport-root-wildcard.md	Documents repro, diagnosis, and validation for #2984.
internal/modulespecifiers/specifiers.go	Adjusts imports-key validation to permit `#/*` root wildcard.
internal/fourslash/tests/autoImport_issue2984_rootWildcardVitest_test.go	Adds regression test asserting `#/...` is top-ranked over deep relative specifiers.

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internal/modulespecifiers/specifiers.go

…validation logic

… not just #/* Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

- Restructure validation logic for clarity - Rewrite fourslash tests using BaselineAutoImports - Delete investigation notes Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

DanielRosenwasser · 2026-03-17T18:11:54Z

...es/reference/fourslash/autoImports/autoImportPackageJsonImportsHashSlashNodenext.baseline.md

+```ts
+// @FileName: /src/features/deep/consumer.ts
+entit/**/
+``````ts


This seems broken, and the next like is missing a file path - what's going on here?

These baselines have always been missing a newline. I'll fix them all in a separate PR but the baseline still shows everything is working.

DanielRosenwasser · 2026-03-17T18:22:00Z

internal/modulespecifiers/specifiers.go

 		entries := top.Entries()
 		for k, value := range entries {
-			if !strings.HasPrefix(k, "#") || k == "#" || strings.HasPrefix(k, "#/") {
+			if k == "#" || k == "#/" || !strings.HasPrefix(k, "#") {


This is surprising - does the blog post need to be updated?

Yeah, --moduleResolution node20 doesn't exist yet. Everything else is right.

But this logic says that "#" and "#/" are invalid entries in "imports" - so am I misunderstanding?

They are, aren't they? You need something after that prefix.

Sorry, to be explicit - the blog post example uses a bare # entry, which is not being used as a prefix.

Omg, sorry, I totally missed that. I was only focused on the highlighted text. Yes, the blog post needs to be updated:

Developer/eg/imports  v24.14.0 ❯ node index.js node:internal/modules/esm/resolve:698 throw new ERR_INVALID_MODULE_SPECIFIER(name, reason, fileURLToPath(base)); ^ TypeError [ERR_INVALID_MODULE_SPECIFIER]: Invalid module "#" is not a valid internal imports specifier name imported from /Users/andrew/Developer/eg/imports/index.js at packageImportsResolve (node:internal/modules/esm/resolve:698:11) at moduleResolve (node:internal/modules/esm/resolve:848:16) at defaultResolve (node:internal/modules/esm/resolve:991:11) at #cachedDefaultResolve (node:internal/modules/esm/loader:719:20) at #resolveAndMaybeBlockOnLoaderThread (node:internal/modules/esm/loader:736:38) at ModuleLoader.resolveSync (node:internal/modules/esm/loader:765:52) at #resolve (node:internal/modules/esm/loader:701:17) at ModuleLoader.getOrCreateModuleJob (node:internal/modules/esm/loader:621:35) at ModuleJob.syncLink (node:internal/modules/esm/module_job:160:33) at ModuleJob.link (node:internal/modules/esm/module_job:245:17) { code: 'ERR_INVALID_MODULE_SPECIFIER' } Node.js v24.14.0 Developer/eg/imports  v24.14.0 ❯ node index.js node:internal/modules/esm/resolve:698 throw new ERR_INVALID_MODULE_SPECIFIER(name, reason, fileURLToPath(base)); ^ TypeError [ERR_INVALID_MODULE_SPECIFIER]: Invalid module "#/" is not a valid internal imports specifier name imported from /Users/andrew/Developer/eg/imports/index.js at packageImportsResolve (node:internal/modules/esm/resolve:698:11) at moduleResolve (node:internal/modules/esm/resolve:848:16) at defaultResolve (node:internal/modules/esm/resolve:991:11) at #cachedDefaultResolve (node:internal/modules/esm/loader:719:20) at #resolveAndMaybeBlockOnLoaderThread (node:internal/modules/esm/loader:736:38) at ModuleLoader.resolveSync (node:internal/modules/esm/loader:765:52) at #resolve (node:internal/modules/esm/loader:701:17) at ModuleLoader.getOrCreateModuleJob (node:internal/modules/esm/loader:621:35) at ModuleJob.syncLink (node:internal/modules/esm/module_job:160:33) at ModuleJob.link (node:internal/modules/esm/module_job:245:17) { code: 'ERR_INVALID_MODULE_SPECIFIER' } Node.js v24.14.0

Investigate and fix auto-import root wildcard handling

3d847b0

Copilot AI review requested due to automatic review settings March 17, 2026 16:17

Copilot started reviewing on behalf of andrewbranch March 17, 2026 16:18 View session

Refactor auto-import test to improve module specifier verification an…

cb06ee2

…d streamline completion checks

Copilot AI reviewed Mar 17, 2026

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internal/modulespecifiers/specifiers.go Outdated Show resolved Hide resolved

internal/modulespecifiers/specifiers.go Outdated Show resolved Hide resolved

andrewbranch and others added 3 commits March 17, 2026 09:24

Add test for root wildcard import restrictions in Node 16 and update …

d85d8e2

…validation logic

Fix #/ imports key validation: allow all #/ keys in nodenext/bundler,…

4858e36

… not just #/* Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Clean up #/ imports key validation and rewrite tests

2ce94b2

- Restructure validation logic for clarity - Rewrite fourslash tests using BaselineAutoImports - Delete investigation notes Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

andrewbranch changed the title ~~Investigate #2984: root wildcard package imports in auto-import~~ Fix auto-import of subpath imports starting with #/ in supported module resolution modes Mar 17, 2026

DanielRosenwasser reviewed Mar 17, 2026

View reviewed changes

andrewbranch requested review from iisaduan and jakebailey March 24, 2026 18:32

jakebailey approved these changes Mar 24, 2026

View reviewed changes

andrewbranch added this pull request to the merge queue Mar 24, 2026

Merged via the queue into microsoft:main with commit 51d05e9 Mar 24, 2026
21 checks passed

andrewbranch deleted the copilot/absent-bedbug branch March 24, 2026 21:26

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Fix auto-import of subpath imports starting with `#/` in supported module resolution modes#3123

Fix auto-import of subpath imports starting with `#/` in supported module resolution modes#3123
andrewbranch merged 5 commits intomicrosoft:mainfrom
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andrewbranch commented Mar 17, 2026 •

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