fix(lsp): cancel executable setup on disposal

packages/lsp/lsp-local/src/index.ts

@@ -117,21 +117,44 @@ export async function apply(ctx: Context, config: Config): Promise<void> {
   const entries = Object.entries(config.servers)
   if (entries.length === 0) throw new Error('lsp-local: servers must contain at least one server')
 
+  const setupAbort = new AbortController()
+  const stopSetupCancellation = ctx.on('internal/plugin', (fiber) => {
+    // An async plugin callback must observe its own disposal before Cordis can
+    // run effect cleanup, because unload otherwise waits for this callback.
+    if (fiber === ctx.fiber && fiber.uid === null) {
+      setupAbort.abort(new Error('lsp-local setup disposed'))
+    }
+  })
+
   // Resolve every server-local setting before registration so a bad later command or bound cannot
   // publish an earlier provider. Registry-level mapping conflicts are rolled back below.
-  const providers = await Promise.all(entries.map(async ([providerId, rawConfig]) => {
-    if (providerId.trim() === '') throw new Error('lsp-local: server ids must be non-empty strings')
-    const resolved = rawConfig as ResolvedServerConfig
-    validateServerConfig(providerId, resolved)
-    const executable = await ctx.subprocess.resolveExecutable(resolved.command, resolved.env)
-    return new LocalLspProvider(
-      providerId,
-      ctx.fs,
-      resolved,
-      executable,
-      spec => ctx.subprocess.spawn(spec),
-    )
-  }))
+  const providers = await (async () => {
+    try {
+      return await Promise.all(entries.map(async ([providerId, rawConfig]) => {
+        if (providerId.trim() === '') throw new Error('lsp-local: server ids must be non-empty strings')
+        const resolved = rawConfig as ResolvedServerConfig
+        validateServerConfig(providerId, resolved)
+        const executable = await ctx.subprocess.resolveExecutable(
+          resolved.command,
+          resolved.env,
+          setupAbort.signal,
+        )
+        setupAbort.signal.throwIfAborted()
+        return new LocalLspProvider(
+          providerId,
+          ctx.fs,
+          resolved,
+          executable,
+          spec => ctx.subprocess.spawn(spec),
+        )
+      }))
+    } catch (error: unknown) {
+      setupAbort.abort(error)
+      throw error
+    } finally {
+      stopSetupCancellation()
+    }
+  })()
 
   ctx.effect(() => {
     const disposers: Array<() => void> = []

packages/lsp/lsp-local/tests/provider.spec.ts

@@ -1,4 +1,4 @@
-import { afterEach, beforeEach, describe, expect, it } from 'vitest'
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest'
 import { chmod, mkdtemp, mkdir, rm, writeFile, realpath } from 'node:fs/promises'
 import { tmpdir } from 'node:os'
 import { delimiter, join } from 'node:path'
@@ -195,6 +195,41 @@ describe('lsp-local provider resolution', () => {
     await ctx.fiber.dispose()
   })
 
+  it('aborts executable resolution when disposed during setup', async () => {
+    const ctx = new Context()
+    await ctx.plugin(Lsp)
+    await ctx.plugin(LocalSubprocessService)
+    await ctx.plugin(LocalFileSystem, { cwd: process.cwd() })
+    const subprocess = ctx.subprocess
+    const lookupStarted = Promise.withResolvers<AbortSignal>()
+    vi.spyOn(subprocess, 'resolveExecutable').mockImplementation(async (_command, _env, signal) => {
+      if (signal === undefined) throw new Error('missing setup signal')
+      lookupStarted.resolve(signal)
+      return await new Promise<string>((_resolve, reject) => {
+        const onAbort = (): void => {
+          reject(signal.reason instanceof Error ? signal.reason : new Error(String(signal.reason)))
+        }
+        signal.addEventListener('abort', onAbort, { once: true })
+        if (signal.aborted) onAbort()
+      })
+    })
+
+    const loading = ctx.plugin(LspLocal, config('pending', {
+      command: 'pending-lsp',
+      extensionToLanguage: { '.ts': 'typescript' },
+    }))
+    const signal = await lookupStarted.promise
+    const unrelated = await ctx.plugin(() => {})
+    await unrelated.dispose()
+    expect(signal.aborted).toBe(false)
+    const disposing = loading.dispose()
+
+    await expect(loading).rejects.toThrow('lsp-local setup disposed')
+    await expect(disposing).resolves.toBeUndefined()
+    expect(signal.aborted).toBe(true)
+    await ctx.fiber.dispose()
+  })
+
   it('rolls back earlier registrations when a later server conflicts', async () => {
     const ctx = new Context()
     await ctx.plugin(Lsp)