Skip to content

Prevent nil dereference during package export resolution #64419

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Draft
Copilot wants to merge 3 commits into
base: main
Choose a base branch
from
+48 −0
Draft

Prevent nil dereference during package export resolution #64419

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
3 commits
Select commit Hold shift + click to select a range
1943007
Initial plan
Copilot Sep 24, 2026
ca7a605
Guard nil package export lookup tables
Copilot Sep 24, 2026
6a139dc
Changes before error encountered
Copilot Sep 24, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
4 changes: 4 additions & 0 deletions tsc/internal/module/resolver.go
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -694,6 +694,10 @@ func (r *resolutionState) loadModuleFromExportsOrImports(
scope *packagejson.InfoCacheEntry,
isImports bool,
) *resolved {
if lookupTable == nil {
return continueSearching()
}

if !strings.HasSuffix(moduleName, "/") && !strings.Contains(moduleName, "*") {
if target, ok := lookupTable.Get(moduleName); ok {
return r.loadModuleFromTargetExportOrImport(extensions, moduleName, scope, isImports, target, "", false /*isPattern*/, moduleName)
Expand Down
44 changes: 44 additions & 0 deletions tsc/internal/module/resolver_test.go
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -6,8 +6,10 @@ import (
"sync/atomic"
"testing"

"github.com/microsoft/TypeScript/tsc/internal/collections"
"github.com/microsoft/TypeScript/tsc/internal/core"
"github.com/microsoft/TypeScript/tsc/internal/module"
"github.com/microsoft/TypeScript/tsc/internal/packagejson"
"github.com/microsoft/TypeScript/tsc/internal/vfs"
"github.com/microsoft/TypeScript/tsc/internal/vfs/vfstest"
)
Expand Down Expand Up @@ -49,6 +51,48 @@ func TestResolveModuleNameTrailingSlash(t *testing.T) {
}
}

func TestResolvePackageImportWithNilLookupTable(t *testing.T) {
t.Parallel()

fs := vfstest.FromMap(map[string]string{
"/repo/package.json": `{"imports": {}}`,
"/repo/src/file.ts": "",
}, true)
fields, err := packagejson.Parse([]byte(`{"imports": {}}`))
if err != nil {
t.Fatal(err)
}
var imports *collections.OrderedMap[string, packagejson.ExportsOrImports]
fields.Imports.Value = imports
cache := packagejson.NewInfoCache("/repo", true)
cache.Set("/repo/package.json", &packagejson.InfoCacheEntry{
PackageDirectory: "/repo",
DirectoryExists: true,
Contents: &packagejson.PackageJson{
Fields: fields,
Parseable: true,
},
})
opts := &core.CompilerOptions{
ModuleResolution: core.ModuleResolutionKindNodeNext,
Module: core.ModuleKindNodeNext,
Target: core.ScriptTargetESNext,
}
resolver := module.NewResolver(module.ResolverOptions{
Host: &resolutionHostStub{fs: fs, cwd: "/repo"},
CompilerOptions: opts,
PackageJsonCache: cache,
})

resolved, _, err := resolver.ResolveModuleName("#missing", "/repo/src/file.ts", core.ModuleKindESNext, nil)
if err != nil {
t.Fatal(err)
}
if resolved.IsResolved() {
t.Fatalf("expected #missing to be unresolved, got %q", resolved.ResolvedFileName)
}
}

// blockingFS wraps a vfs.FS and forces FileExists calls for `targetPath` to
// block on `gate` until released. Each caller sends on `arrived` when it
// reaches the gate. This is used to deterministically reproduce the
Expand Down