feat: configurable shell selection + desktop settings UI (#20602)

packages/opencode/test/config/config.test.ts

@@ -55,6 +55,8 @@ const it = testEffect(layer)
 const load = () => Effect.runPromise(Config.Service.use((svc) => svc.get()).pipe(Effect.scoped, Effect.provide(layer)))
 const save = (config: Config.Info) =>
   Effect.runPromise(Config.Service.use((svc) => svc.update(config)).pipe(Effect.scoped, Effect.provide(layer)))
+const saveGlobal = (config: Config.Info) =>
+  Effect.runPromise(Config.Service.use((svc) => svc.updateGlobal(config)).pipe(Effect.scoped, Effect.provide(layer)))
 const clear = (wait = false) =>
   Effect.runPromise(Config.Service.use((svc) => svc.invalidate(wait)).pipe(Effect.scoped, Effect.provide(layer)))
 const listDirs = () =>
@@ -142,6 +144,106 @@ test("loads JSON config file", async () => {
   })
 })
 
+test("loads shell config field", async () => {
+  await using tmp = await tmpdir({
+    init: async (dir) => {
+      await writeConfig(dir, {
+        $schema: "https://opencode.ai/config.json",
+        shell: "bash",
+      })
+    },
+  })
+  await Instance.provide({
+    directory: tmp.path,
+    fn: async () => {
+      const config = await load()
+      expect(config.shell).toBe("bash")
+    },
+  })
+})
+
+test("updates config and preserves empty shell sentinel", async () => {
+  await using tmp = await tmpdir({
+    init: async (dir) => {
+      await writeConfig(
+        dir,
+        {
+          $schema: "https://opencode.ai/config.json",
+          shell: "bash",
+        },
+        "config.json",
+      )
+    },
+  })
+  await Instance.provide({
+    directory: tmp.path,
+    fn: async () => {
+      await save({ shell: "" })
+
+      const writtenConfig = await Filesystem.readJson<{ shell?: string }>(path.join(tmp.path, "config.json"))
+      expect(writtenConfig.shell).toBe("")
+    },
+  })
+})
+
+test("updates global config and omits empty shell key in json", async () => {
+  await using tmp = await tmpdir({
+    init: async (dir) => {
+      await writeConfig(dir, {
+        $schema: "https://opencode.ai/config.json",
+        shell: "bash",
+      })
+    },
+  })
+
+  const prev = Global.Path.config
+  ;(Global.Path as { config: string }).config = tmp.path
+  await clear(true)
+
+  try {
+    await saveGlobal({ shell: "" })
+
+    const writtenConfig = await Filesystem.readJson<{ shell?: string }>(path.join(tmp.path, "opencode.json"))
+    expect("shell" in writtenConfig).toBe(false)
+  } finally {
+    ;(Global.Path as { config: string }).config = prev
+    await clear(true)
+  }
+})
+
+test("updates global config and omits empty shell key in jsonc", async () => {
+  await using tmp = await tmpdir({
+    init: async (dir) => {
+      await Filesystem.write(
+        path.join(dir, "opencode.jsonc"),
+        JSON.stringify({
+          $schema: "https://opencode.ai/config.json",
+          shell: "bash",
+          model: "test/model",
+        }),
+      )
+    },
+  })
+
+  const prev = Global.Path.config
+  ;(Global.Path as { config: string }).config = tmp.path
+  await clear(true)
+
+  try {
+    await saveGlobal({ shell: "" })
+
+    const file = path.join(tmp.path, "opencode.jsonc")
+    const writtenConfig = await Filesystem.readText(file)
+    const parsed = ConfigParse.schema(Config.Info.zod, ConfigParse.jsonc(writtenConfig, file), file)
+    expect(writtenConfig).not.toContain('"shell"')
+    expect(parsed.shell).toBeUndefined()
+    expect(parsed.model).toBe("test/model")
+  } finally {
+    ;(Global.Path as { config: string }).config = prev
+    await clear(true)
+  }
+})
+
 test("loads formatter boolean config", async () => {
   await using tmp = await tmpdir({
     init: async (dir) => {

packages/opencode/test/pty/pty-shell.test.ts

@@ -67,3 +67,38 @@ describe("pty shell args", () => {
     )
   }
 })
+
+describe("pty configured shell", () => {
+  test(
+    "uses configured shell for default PTY command",
+    async () => {
+      const configured = process.platform === "win32" ? Bun.which("pwsh") || Bun.which("powershell") : Bun.which("bash")
+      if (!configured) return
+
+      await using dir = await tmpdir({
+        config: { shell: Shell.name(configured) },
+      })
+      await Instance.provide({
+        directory: dir.path,
+        fn: () =>
+          AppRuntime.runPromise(
+            Effect.gen(function* () {
+              const pty = yield* Pty.Service
+              const info = yield* pty.create({ title: "configured" })
+              try {
+                if (process.platform === "win32") {
+                  expect(info.command.toLowerCase()).toBe(configured.toLowerCase())
+                } else {
+                  expect(info.command).toBe(configured)
+                }
+                expect(info.args).toEqual(process.platform === "win32" ? [] : ["-l"])
+              } finally {
+                yield* pty.remove(info.id)
+              }
+            }),
+          ),
+      })
+    },
+    { timeout: 30000 },
+  )
+})

packages/opencode/test/session/prompt.test.ts

@@ -316,9 +316,11 @@ const addSubtask = (sessionID: SessionID, messageID: MessageID, model = ref) =>
   })
 
 const boot = Effect.fn("test.boot")(function* (input?: { title?: string }) {
+  const config = yield* Config.Service
   const prompt = yield* SessionPrompt.Service
   const run = yield* SessionRunState.Service
   const sessions = yield* Session.Service
+  yield* config.get()
   const chat = yield* sessions.create(input ?? { title: "Pinned" })
   return { prompt, run, sessions, chat }
 })
@@ -1078,6 +1080,32 @@ unix("shell completes a fast command on the preferred shell", () =>
   ),
 )
 
+unix(
+  "shell uses configured shell over env shell",
+  () =>
+    withSh(() =>
+      provideTmpdirInstance(
+        (_dir) =>
+          Effect.gen(function* () {
+            if (!Bun.which("bash")) return
+
+            const { prompt, chat } = yield* boot()
+            const result = yield* prompt.shell({
+              sessionID: chat.id,
+              agent: "build",
+              command: "[[ 1 -eq 1 ]] && printf configured",
+            })
+
+            const tool = completedTool(result.parts)
+            if (!tool) return
+            expect(tool.state.output).toContain("configured")
+          }),
+        { git: true, config: { ...cfg, shell: "bash" } },
+      ),
+    ),
+  30_000,
+)
+
 unix("shell commands can change directory after startup", () =>
   provideTmpdirInstance(
     (dir) =>
@@ -1263,6 +1291,45 @@ it.live(
   3_000,
 )
 
+unix(
+  "command ! expansion uses configured shell over env shell",
+  () =>
+    withSh(() =>
+      provideTmpdirServer(
+        ({ llm }) =>
+          Effect.gen(function* () {
+            if (!Bun.which("bash")) return
+
+            const { prompt, chat } = yield* boot()
+            yield* llm.text("done")
+
+            const result = yield* prompt.command({
+              sessionID: chat.id,
+              command: "probe",
+              arguments: "",
+            })
+
+            expect(result.info.role).toBe("assistant")
+            const inputs = yield* llm.inputs
+            expect(JSON.stringify(inputs.at(-1)?.messages)).toContain("configured")
+          }),
+        {
+          git: true,
+          config: (url) => ({
+            ...providerCfg(url),
+            shell: "bash",
+            command: {
+              probe: {
+                template: "Probe: !`[[ 1 -eq 1 ]] && printf configured`",
+              },
+            },
+          }),
+        },
+      ),
+    ),
+  30_000,
+)
+
 unix(
   "cancel interrupts shell and resolves cleanly",
   () =>

packages/opencode/test/shell/shell.test.ts

@@ -2,6 +2,7 @@ import { describe, expect, test } from "bun:test"
 import path from "path"
 import { Shell } from "../../src/shell/shell"
 import { Filesystem } from "../../src/util"
+import { which } from "../../src/util/which"
 
 const withShell = async (shell: string | undefined, fn: () => void | Promise<void>) => {
   const prev = process.env.SHELL
@@ -39,6 +40,20 @@ describe("shell", () => {
     expect(Shell.posix("C:/tools/pwsh.exe")).toBe(false)
   })
 
+  test("falls back when configured shell cannot be resolved", async () => {
+    await withShell(undefined, async () => {
+      const preferred = Shell.preferred()
+      const acceptable = Shell.acceptable()
+      expect(Shell.preferred("opencode-missing-shell")).toBe(preferred)
+      expect(Shell.acceptable("opencode-missing-shell")).toBe(acceptable)
+    })
+  })
+
+  test("falls back for terminal-only acceptable shells", () => {
+    expect(Shell.name(Shell.acceptable("fish"))).not.toBe("fish")
+    expect(Shell.name(Shell.acceptable("nu"))).not.toBe("nu")
+  })
+
   if (process.platform === "win32") {
     test("rejects blacklisted shells case-insensitively", async () => {
       await withShell("NU.EXE", async () => {
@@ -62,8 +77,19 @@ describe("shell", () => {
       })
     })
 
+    test("resolves bare bash to Git Bash before PATH", async () => {
+      const bash = Shell.gitbash()
+      if (!bash) return
+      expect(Shell.acceptable("bash")).toBe(bash)
+      expect(Shell.preferred("bash")).toBe(bash)
+      await withShell("bash", async () => {
+        expect(Shell.acceptable()).toBe(bash)
+        expect(Shell.preferred()).toBe(bash)
+      })
+    })
+
     test("resolves bare PowerShell shells", async () => {
-      const shell = Bun.which("pwsh") || Bun.which("powershell")
+      const shell = which("pwsh") || which("powershell")
       if (!shell) return
       await withShell(path.win32.basename(shell), async () => {
         expect(Shell.preferred()).toBe(shell)

packages/opencode/test/tool/bash.test.ts

@@ -2,6 +2,7 @@ import { describe, expect, test } from "bun:test"
 import { Effect, Layer, ManagedRuntime } from "effect"
 import os from "os"
 import path from "path"
+import { Config } from "../../src/config"
 import { Shell } from "../../src/shell/shell"
 import { BashTool } from "../../src/tool/bash"
 import { Instance } from "../../src/project/instance"
@@ -21,6 +22,7 @@ const runtime = ManagedRuntime.make(
     AppFileSystem.defaultLayer,
     Plugin.defaultLayer,
     Truncate.defaultLayer,
+    Config.defaultLayer,
     Agent.defaultLayer,
   ),
 )
@@ -153,6 +155,33 @@ describe("tool.bash", () => {
       },
     })
   })
+
+  test("falls back from terminal-only configured shell", async () => {
+    await using tmp = await tmpdir({
+      config: { shell: "fish" },
+    })
+    await Instance.provide({
+      directory: tmp.path,
+      fn: async () => {
+        const bash = await initBash()
+        const fallback = Shell.name(Shell.acceptable("fish"))
+        expect(fallback).not.toBe("fish")
+        expect(bash.description).toContain(fallback)
+
+        const result = await Effect.runPromise(
+          bash.execute(
+            {
+              command: "echo fallback",
+              description: "Echo fallback text",
+            },
+            ctx,
+          ),
+        )
+        expect(result.metadata.exit).toBe(0)
+        expect(result.output).toContain("fallback")
+      },
+    })
+  })
 })
 
 describe("tool.bash permissions", () => {