feat(core): add V2 formatter runtime (#39564)

Author: jlongster

packages/core/src/file-mutation.ts

@@ -5,6 +5,7 @@ import { Context, Effect, Layer, Schema } from "effect"
 import { dirname } from "path"
 import { KeyedMutex } from "./effect/keyed-mutex"
 import { FSUtil } from "@opencode-ai/util/fs-util"
+import { Bom } from "@opencode-ai/util/bom"
 
 export interface Target {
   readonly canonical: string
@@ -108,13 +109,13 @@ const layer = Layer.effect(
     const writeTextPreservingBom = Effect.fn("FileMutation.writeTextPreservingBom")((input: TextWriteInput) =>
       withTargetLock(input.target)(
         Effect.gen(function* () {
-          const next = splitBom(input.content)
+          const next = Bom.split(input.content)
           const current = yield* fs
             .readFile(input.target.canonical)
             .pipe(Effect.catchReason("PlatformError", "NotFound", () => Effect.succeed(undefined)))
           yield* fs.writeWithDirs(
             input.target.canonical,
-            joinBom(next.text, Boolean(current && hasUtf8Bom(current)) || next.bom),
+            Bom.join(next.text, Boolean(current && Bom.has(current)) || next.bom),
           )
           return writeResult(input.target, current !== undefined)
         }),
@@ -172,20 +173,6 @@ const layer = Layer.effect(
   }),
 )
 
-function splitBom(text: string) {
-  const stripped = text.replace(/^\uFEFF+/, "")
-  return { bom: stripped.length !== text.length, text: stripped }
-}
-
-function joinBom(text: string, bom: boolean) {
-  const stripped = splitBom(text).text
-  return bom ? `\uFEFF${stripped}` : stripped
-}
-
-function hasUtf8Bom(content: Uint8Array) {
-  return content[0] === 0xef && content[1] === 0xbb && content[2] === 0xbf
-}
-
 function sameBytes(left: Uint8Array, right: Uint8Array) {
   if (left.length !== right.length) return false
   return left.every((byte, index) => byte === right[index])

packages/core/src/formatter.ts

@@ -0,0 +1,157 @@
+export * as Formatter from "./formatter"
+
+import { Context, Effect, Layer, Schema } from "effect"
+import { ChildProcess } from "effect/unstable/process"
+import path from "path"
+import { makeLocationNode } from "@opencode-ai/util/effect/app-node"
+import { FSUtil } from "@opencode-ai/util/fs-util"
+import { Npm } from "@opencode-ai/util/npm"
+import { AppProcess } from "@opencode-ai/util/process"
+import { Config } from "./config"
+import { Location } from "./location"
+import { make, type Info } from "./formatter/builtins"
+
+export const Status = Schema.Struct({
+  name: Schema.String,
+  extensions: Schema.Array(Schema.String),
+  enabled: Schema.Boolean,
+}).annotate({ identifier: "FormatterStatus" })
+export type Status = typeof Status.Type
+
+export interface Interface {
+  readonly init: () => Effect.Effect<void>
+  readonly status: () => Effect.Effect<Status[]>
+  readonly file: (filepath: string) => Effect.Effect<boolean>
+}
+
+export class Service extends Context.Service<Service, Interface>()("@opencode/v2/Formatter") {}
+
+const layer = Layer.effect(
+  Service,
+  Effect.gen(function* () {
+    const config = yield* Config.Service
+    const fs = yield* FSUtil.Service
+    const location = yield* Location.Service
+    const npm = yield* Npm.Service
+    const processes = yield* AppProcess.Service
+    const commands = new Map<string, string[] | false>()
+    let formatters: Info[] = []
+
+    const load = yield* Effect.cached(
+      Effect.gen(function* () {
+        const configured = Config.latest(yield* config.entries(), "formatter")
+        if (!configured) {
+          yield* Effect.logInfo("all formatters are disabled")
+          return
+        }
+
+        const builtIns = make({
+          directory: location.directory,
+          worktree: location.project.directory,
+          fs,
+          npm,
+          processes,
+        })
+        formatters = builtIns
+        if (configured === true) return
+        if (configured.ruff?.disabled || configured.uv?.disabled) {
+          formatters = formatters.filter((formatter) => formatter.name !== "ruff" && formatter.name !== "uv")
+        }
+
+        for (const [name, entry] of Object.entries(configured)) {
+          const index = formatters.findIndex((formatter) => formatter.name === name)
+          if (entry.disabled) {
+            if (index !== -1) formatters.splice(index, 1)
+            continue
+          }
+
+          const builtIn = builtIns.find((formatter) => formatter.name === name)
+          const formatter: Info = {
+            name,
+            extensions: entry.extensions ?? builtIn?.extensions ?? [],
+            environment: { ...builtIn?.environment, ...entry.environment },
+            enabled:
+              builtIn && !entry.command ? builtIn.enabled : Effect.succeed(entry.command ? [...entry.command] : false),
+          }
+          if (index === -1) formatters.push(formatter)
+          else formatters[index] = formatter
+        }
+      }).pipe(Effect.withSpan("Formatter.load")),
+    )
+
+    const command = Effect.fnUntraced(function* (formatter: Info) {
+      const cached = commands.get(formatter.name)
+      if (cached !== undefined) return cached
+      const result = yield* formatter.enabled
+      if (result !== false) commands.set(formatter.name, result)
+      return result
+    })
+
+    const init = Effect.fn("Formatter.init")(function* () {
+      yield* load
+    })
+
+    const status = Effect.fn("Formatter.status")(function* () {
+      yield* load
+      return yield* Effect.forEach(formatters, (formatter) =>
+        command(formatter).pipe(
+          Effect.map((enabled) => ({
+            name: formatter.name,
+            extensions: [...formatter.extensions],
+            enabled: enabled !== false,
+          })),
+        ),
+      )
+    })
+
+    const file = Effect.fn("Formatter.file")(function* (filepath: string) {
+      yield* load
+      const matching = formatters.filter((formatter) =>
+        formatter.extensions.includes(path.extname(filepath)),
+      )
+
+      for (const formatter of matching) {
+        const enabled = yield* command(formatter)
+        if (enabled === false) continue
+        const cmd = enabled.map((argument) => argument.replace("$FILE", filepath))
+        yield* Effect.logInfo("formatting file", { file: filepath, command: cmd })
+        const result = yield* processes
+          .run(
+            ChildProcess.make(cmd[0], cmd.slice(1), {
+              cwd: location.directory,
+              env: formatter.environment,
+              extendEnv: true,
+              stdin: "ignore",
+              stdout: "ignore",
+              stderr: "ignore",
+            }),
+          )
+          .pipe(
+            Effect.catch((error) =>
+              Effect.logError("failed to format file", {
+                file: filepath,
+                command: cmd,
+                error: error.message,
+              }).pipe(Effect.as(undefined)),
+            ),
+          )
+        if (!result) continue
+        if (result.exitCode === 0) return true
+        yield* Effect.logError("formatter exited unsuccessfully", {
+          file: filepath,
+          command: cmd,
+          exitCode: result.exitCode,
+        })
+      }
+      return false
+    })
+
+    return Service.of({ init, status, file })
+  }),
+)
+
+export const node = makeLocationNode({
+  service: Service,
+  layer,
+  deps: [Config.node, FSUtil.node, Location.node, Npm.node, AppProcess.node],
+})