fix: handle undefined from Npm.which in all callers

Npm.which now returns undefined instead of throwing when binary not found.
Update all callers to check for undefined and return early.
Avoid explicit union types by using a resolved variable pattern.

packages/opencode/src/format/formatter.ts

@@ -92,7 +92,9 @@ export const oxfmt: Info = {
         devDependencies?: Record<string, string>
       }>(item)
       if (json.dependencies?.oxfmt || json.devDependencies?.oxfmt) {
-        return [await Npm.which("oxfmt"), "$FILE"]
+        const bin = await Npm.which("oxfmt")
+        if (!bin) return false
+        return [bin, "$FILE"]
       }
     }
     return false
@@ -134,7 +136,9 @@ export const biome: Info = {
     for (const config of configs) {
       const found = await Filesystem.findUp(config, Instance.directory, Instance.worktree)
       if (found.length > 0) {
-        return [await Npm.which("@biomejs/biome"), "check", "--write", "$FILE"]
+        const bin = await Npm.which("@biomejs/biome")
+        if (!bin) return false
+        return [bin, "check", "--write", "$FILE"]
       }
     }
     return false

packages/opencode/src/lsp/server.ts

@@ -103,7 +103,9 @@ export namespace LSPServer {
       const tsserver = Module.resolve("typescript/lib/tsserver.js", Instance.directory)
       log.info("typescript server", { tsserver })
       if (!tsserver) return
-      const proc = spawn(await Npm.which("typescript-language-server"), ["--stdio"], {
+      const bin = await Npm.which("typescript-language-server")
+      if (!bin) return
+      const proc = spawn(bin, ["--stdio"], {
         cwd: root,
         env: {
           ...process.env,
@@ -129,7 +131,9 @@ export namespace LSPServer {
       const args: string[] = []
       if (!binary) {
         if (Flag.OPENCODE_DISABLE_LSP_DOWNLOAD) return
-        binary = await Npm.which("@vue/language-server")
+        const resolved = await Npm.which("@vue/language-server")
+        if (!resolved) return
+        binary = resolved
       }
       args.push("--stdio")
       const proc = spawn(binary, args, {
@@ -322,6 +326,7 @@ export namespace LSPServer {
         const resolved = Module.resolve("biome", root)
         if (!resolved) return
         bin = await Npm.which("biome")
+        if (!bin) return
         args = ["lsp-proxy", "--stdio"]
       }
 
@@ -488,7 +493,9 @@ export namespace LSPServer {
       const args = []
       if (!binary) {
         if (Flag.OPENCODE_DISABLE_LSP_DOWNLOAD) return
-        binary = await Npm.which("pyright")
+        const resolved = await Npm.which("pyright")
+        if (!resolved) return
+        binary = resolved
       }
       args.push("--stdio")
 
@@ -1003,7 +1010,9 @@ export namespace LSPServer {
       const args: string[] = []
       if (!binary) {
         if (Flag.OPENCODE_DISABLE_LSP_DOWNLOAD) return
-        binary = await Npm.which("svelte-language-server")
+        const resolved = await Npm.which("svelte-language-server")
+        if (!resolved) return
+        binary = resolved
       }
       args.push("--stdio")
       const proc = spawn(binary, args, {
@@ -1035,7 +1044,9 @@ export namespace LSPServer {
       const args: string[] = []
       if (!binary) {
         if (Flag.OPENCODE_DISABLE_LSP_DOWNLOAD) return
-        binary = await Npm.which("@astrojs/language-server")
+        const resolved = await Npm.which("@astrojs/language-server")
+        if (!resolved) return
+        binary = resolved
       }
       args.push("--stdio")
       const proc = spawn(binary, args, {
@@ -1284,7 +1295,9 @@ export namespace LSPServer {
       const args: string[] = []
       if (!binary) {
         if (Flag.OPENCODE_DISABLE_LSP_DOWNLOAD) return
-        binary = await Npm.which("yaml-language-server")
+        const resolved = await Npm.which("yaml-language-server")
+        if (!resolved) return
+        binary = resolved
       }
       args.push("--stdio")
       const proc = spawn(binary, args, {
@@ -1449,7 +1462,9 @@ export namespace LSPServer {
       const args: string[] = []
       if (!binary) {
         if (Flag.OPENCODE_DISABLE_LSP_DOWNLOAD) return
-        binary = await Npm.which("intelephense")
+        const resolved = await Npm.which("intelephense")
+        if (!resolved) return
+        binary = resolved
       }
       args.push("--stdio")
       const proc = spawn(binary, args, {
@@ -1531,7 +1546,9 @@ export namespace LSPServer {
       const args: string[] = []
       if (!binary) {
         if (Flag.OPENCODE_DISABLE_LSP_DOWNLOAD) return
-        binary = await Npm.which("bash-language-server")
+        const resolved = await Npm.which("bash-language-server")
+        if (!resolved) return
+        binary = resolved
       }
       args.push("start")
       const proc = spawn(binary, args, {
@@ -1724,7 +1741,9 @@ export namespace LSPServer {
       const args: string[] = []
       if (!binary) {
         if (Flag.OPENCODE_DISABLE_LSP_DOWNLOAD) return
-        binary = await Npm.which("dockerfile-language-server-nodejs")
+        const resolved = await Npm.which("dockerfile-language-server-nodejs")
+        if (!resolved) return
+        binary = resolved
       }
       args.push("--stdio")
       const proc = spawn(binary, args, {

packages/opencode/src/npm/index.ts

@@ -175,7 +175,7 @@ export namespace Npm {
     await rm(path.join(dir, "package-lock.json"), { force: true })
     await add(pkg)
     const resolved = await pick()
-    if (!resolved) throw new Error(`No binary found for package "${pkg}" after install`)
+    if (!resolved) return
     return path.join(binDir, resolved)
   }
 }