fix: prefer a runnable opencode binary for cli run

src/cli/run/opencode-binary-resolver.test.ts

@@ -0,0 +1,102 @@
+import { describe, expect, it } from "bun:test"
+import { delimiter, join } from "node:path"
+import {
+  buildPathWithBinaryFirst,
+  collectCandidateBinaryPaths,
+  findWorkingOpencodeBinary,
+  withWorkingOpencodePath,
+} from "./opencode-binary-resolver"
+
+describe("collectCandidateBinaryPaths", () => {
+  it("includes Bun.which results first and removes duplicates", () => {
+    // given
+    const pathEnv = ["/bad", "/good"].join(delimiter)
+    const which = (command: string): string | undefined => {
+      if (command === "opencode") return "/bad/opencode"
+      return undefined
+    }
+
+    // when
+    const candidates = collectCandidateBinaryPaths(pathEnv, which, "darwin")
+
+    // then
+    expect(candidates[0]).toBe("/bad/opencode")
+    expect(candidates).toContain("/good/opencode")
+    expect(candidates.filter((candidate) => candidate === "/bad/opencode")).toHaveLength(1)
+  })
+})
+
+describe("findWorkingOpencodeBinary", () => {
+  it("returns the first runnable candidate", async () => {
+    // given
+    const pathEnv = ["/bad", "/good"].join(delimiter)
+    const which = (command: string): string | undefined => {
+      if (command === "opencode") return "/bad/opencode"
+      return undefined
+    }
+    const probe = async (binaryPath: string): Promise<boolean> =>
+      binaryPath === "/good/opencode"
+
+    // when
+    const resolved = await findWorkingOpencodeBinary(pathEnv, probe, which, "darwin")
+
+    // then
+    expect(resolved).toBe("/good/opencode")
+  })
+})
+
+describe("buildPathWithBinaryFirst", () => {
+  it("prepends the binary directory and avoids duplicate entries", () => {
+    // given
+    const binaryPath = "/good/opencode"
+    const pathEnv = ["/bad", "/good", "/other"].join(delimiter)
+
+    // when
+    const updated = buildPathWithBinaryFirst(pathEnv, binaryPath)
+
+    // then
+    expect(updated).toBe(["/good", "/bad", "/other"].join(delimiter))
+  })
+})
+
+describe("withWorkingOpencodePath", () => {
+  it("temporarily updates PATH while starting the server", async () => {
+    // given
+    const originalPath = process.env.PATH
+    process.env.PATH = ["/bad", "/other"].join(delimiter)
+    const finder = async (): Promise<string | null> => "/good/opencode"
+    let observedPath = ""
+
+    // when
+    await withWorkingOpencodePath(
+      async () => {
+        observedPath = process.env.PATH ?? ""
+      },
+      finder,
+    )
+
+    // then
+    expect(observedPath).toBe(["/good", "/bad", "/other"].join(delimiter))
+    expect(process.env.PATH).toBe(["/bad", "/other"].join(delimiter))
+    process.env.PATH = originalPath
+  })
+
+  it("restores PATH when server startup fails", async () => {
+    // given
+    const originalPath = process.env.PATH
+    process.env.PATH = ["/bad", "/other"].join(delimiter)
+    const finder = async (): Promise<string | null> => join("/good", "opencode")
+
+    // when & then
+    await expect(
+      withWorkingOpencodePath(
+        async () => {
+          throw new Error("boom")
+        },
+        finder,
+      ),
+    ).rejects.toThrow("boom")
+    expect(process.env.PATH).toBe(["/bad", "/other"].join(delimiter))
+    process.env.PATH = originalPath
+  })
+})