refactor: drop namespace proof-of-concept code changes

refactor: migrate namespace tooling to self-reexport pattern
2026-04-16 11:18:33 -04:00 · 2026-04-16 11:17:10 -04:00
2 changed files with 356 additions and 552 deletions
--- a/packages/opencode/script/unwrap-namespace.ts
+++ b/packages/opencode/script/unwrap-namespace.ts
@ -1,21 +1,26 @@
 #!/usr/bin/env bun
 /**
- * Unwrap a TypeScript `export namespace` into flat exports + barrel.
+ * Unwrap a TypeScript `export namespace` into flat exports with self-reexport.
 *
 * Usage:
- *   bun script/unwrap-namespace.ts src/bus/index.ts
+ *   bun script/unwrap-namespace.ts src/session/session.ts           # convert namespace
- *   bun script/unwrap-namespace.ts src/bus/index.ts --dry-run
+ *   bun script/unwrap-namespace.ts src/session/session.ts --dry-run
- *   bun script/unwrap-namespace.ts src/pty/index.ts --name service   # avoid collision with pty.ts
+ *   bun script/unwrap-namespace.ts src/pty/index.ts --name service  # avoid filename collision
 *   bun script/unwrap-namespace.ts src/config/config.ts --retrofit  # already flat, add self-reexport
 *
- * What it does:
+ * Default mode:
- *   1. Reads the file and finds the `export namespace Foo { ... }` block
+ *   1. Finds `export namespace Foo { ... }` (ast-grep)
- *      (uses ast-grep for accurate AST-based boundary detection)
+ *   2. Removes wrapper, dedents body, fixes self-references
- *   2. Removes the namespace wrapper and dedents the body
+ *   3. Appends `export * as Foo from "./file"` to the file (self-reexport)
- *   3. Fixes self-references (e.g. Config.PermissionAction → PermissionAction)
+ *   4. Rewrites consumer imports to point at the file directly
- *   4. If the file is index.ts, renames it to <lowercase-name>.ts
+ *
- *   5. Creates/updates index.ts with `export * as Foo from "./<file>"`
+ * Retrofit mode (--retrofit):
- *   6. Rewrites import paths across src/, test/, and script/
+ *   File already has flat exports (from previous barrel migration).
- *   7. Fixes sibling imports within the same directory
+ *   1. Reads the barrel index.ts to find the namespace name
 *   2. Adds `export * as Foo from "./file"` to the source file
 *   3. Rewrites consumers from barrel import to direct file import
 *
 * Does NOT create barrel index.ts files.
 *
 * Requires: ast-grep (`brew install ast-grep` or `cargo install ast-grep`)
 */
@ -25,11 +30,12 @@ import fs from "fs"
 const args = process.argv.slice(2)
 const dryRun = args.includes("--dry-run")
 const retrofit = args.includes("--retrofit")
 const nameFlag = args.find((a, i) => args[i - 1] === "--name")
 const filePath = args.find((a) => !a.startsWith("--") && args[args.indexOf(a) - 1] !== "--name")
 if (!filePath) {
-  console.error("Usage: bun script/unwrap-namespace.ts <file> [--dry-run] [--name <impl-name>]")
+  console.error("Usage: bun script/unwrap-namespace.ts <file> [--dry-run] [--name <impl>] [--retrofit]")
  process.exit(1)
 }
@ -39,11 +45,76 @@ if (!fs.existsSync(absPath)) {
  process.exit(1)
 }
 const srcRoot = path.resolve("src")
 const dir = path.dirname(absPath)
 const basename = path.basename(absPath, ".ts")
 // ---------------------------------------------------------------------------
 // Barrel map: parse an index.ts to get namespace→file mapping
 // ---------------------------------------------------------------------------
 function parseBarrelMap(indexPath: string): Record<string, string> {
  const map: Record<string, string> = {}
  if (!fs.existsSync(indexPath)) return map
  const content = fs.readFileSync(indexPath, "utf-8")
  const re = /export\s+\*\s+as\s+(\w+)\s+from\s+["']\.\/([^"']+)["']/g
  for (const m of content.matchAll(re)) {
    map[m[1]] = m[2].replace(/\.ts$/, "")
  }
  return map
 }
 // ---------------------------------------------------------------------------
 // Retrofit mode: file is already flat, just add self-reexport + fix imports
 // ---------------------------------------------------------------------------
 if (retrofit) {
  const indexFile = path.join(dir, "index.ts")
  const barrelMap = parseBarrelMap(indexFile)
  // Find this file's namespace name from the barrel
  const relName = basename
  let nsName: string | undefined
  for (const [ns, file] of Object.entries(barrelMap)) {
    if (file === relName) {
      nsName = ns
      break
    }
  }
  if (!nsName) {
    console.error(`Could not find namespace for ${basename}.ts in ${indexFile}`)
    console.error("Barrel map:", barrelMap)
    process.exit(1)
  }
  console.log(`Retrofit: ${basename}.ts → add self-reexport as ${nsName}`)
  // Check if self-reexport already exists
  const content = fs.readFileSync(absPath, "utf-8")
  const selfReexport = `export * as ${nsName} from "./${basename}"`
  if (content.includes(selfReexport)) {
    console.log("Self-reexport already present, skipping file modification")
  } else if (!dryRun) {
    const trimmed = content.endsWith("\n") ? content : content + "\n"
    fs.writeFileSync(absPath, trimmed + selfReexport + "\n")
    console.log(`Added: ${selfReexport}`)
  } else {
    console.log(`Would add: ${selfReexport}`)
  }
  // Now rewrite consumers (same logic as default mode, below)
  rewriteConsumers(nsName, absPath, basename, dir)
  process.exit(0)
 }
 // ---------------------------------------------------------------------------
 // Default mode: unwrap namespace
 // ---------------------------------------------------------------------------
 const src = fs.readFileSync(absPath, "utf-8")
 const lines = src.split("\n")
 // Use ast-grep to find the namespace boundaries accurately.
 // This avoids false matches from braces in strings, templates, comments, etc.
 const astResult = Bun.spawnSync(
  ["ast-grep", "run", "--pattern", "export namespace $NAME { $$$BODY }", "--lang", "typescript", "--json", absPath],
  { stdout: "pipe", stderr: "pipe" },
@ -61,34 +132,29 @@ const matches = JSON.parse(astResult.stdout.toString()) as Array<{
 }>
 if (matches.length === 0) {
-  console.error("No `export namespace Foo { ... }` found in file")
+  console.error("No `export namespace Foo { ... }` found. Use --retrofit for already-converted files.")
  process.exit(1)
 }
 if (matches.length > 1) {
  console.error(`Found ${matches.length} namespaces — this script handles one at a time`)
  console.error("Namespaces found:")
  for (const m of matches) console.error(`  ${m.metaVariables.single.NAME.text} (line ${m.range.start.line + 1})`)
  process.exit(1)
 }
 const match = matches[0]
 const nsName = match.metaVariables.single.NAME.text
-const nsLine = match.range.start.line // 0-indexed
+const nsLine = match.range.start.line
-const closeLine = match.range.end.line // 0-indexed, the line with closing `}`
+const closeLine = match.range.end.line
 console.log(`Found: export namespace ${nsName} { ... }`)
 console.log(`  Lines ${nsLine + 1}–${closeLine + 1} (${closeLine - nsLine + 1} lines)`)
-// Build the new file content:
+// Unwrap: remove namespace wrapper, dedent body
 // 1. Everything before the namespace declaration (imports, etc.)
 // 2. The namespace body, dedented by one level (2 spaces)
 // 3. Everything after the closing brace (rare, but possible)
 const before = lines.slice(0, nsLine)
 const body = lines.slice(nsLine + 1, closeLine)
 const after = lines.slice(closeLine + 1)
 // Dedent: remove exactly 2 leading spaces from each line
 const dedented = body.map((line) => {
  if (line === "") return ""
  if (line.startsWith("  ")) return line.slice(2)
@ -97,9 +163,7 @@ const dedented = body.map((line) => {
 let newContent = [...before, ...dedented, ...after].join("\n")
-// --- Fix self-references ---
+// Fix self-references (Foo.Bar → Bar when Bar is exported from this file)
 // After unwrapping, references like `Config.PermissionAction` inside the same file
 // need to become just `PermissionAction`. Only fix code positions, not strings.
 const exportedNames = new Set<string>()
 const exportRegex = /export\s+(?:const|function|class|interface|type|enum|abstract\s+class)\s+(\w+)/g
 for (const line of dedented) {
@ -122,7 +186,6 @@ for (const line of dedented) {
 let selfRefCount = 0
 if (exportedNames.size > 0) {
  const fixedLines = newContent.split("\n").map((line) => {
    // Split line into string-literal and code segments to avoid replacing inside strings
    const segments: Array<{ text: string; isString: boolean }> = []
    let i = 0
    let current = ""
@ -186,120 +249,199 @@ if (exportedNames.size > 0) {
  newContent = fixedLines.join("\n")
 }
-// Figure out file naming
+// Handle index.ts rename
 const dir = path.dirname(absPath)
 const basename = path.basename(absPath, ".ts")
 const isIndex = basename === "index"
 const implName = nameFlag ?? (isIndex ? nsName.replace(/([a-z])([A-Z])/g, "$1-$2").toLowerCase() : basename)
-const implFile = path.join(dir, `${implName}.ts`)
+const implFile = isIndex ? path.join(dir, `${implName}.ts`) : absPath
-const indexFile = path.join(dir, "index.ts")
+
-const barrelLine = `export * as ${nsName} from "./${implName}"\n`
+// Add self-reexport at the bottom
 const selfReexport = `export * as ${nsName} from "./${implName}"`
 if (!newContent.endsWith("\n")) newContent += "\n"
 newContent += selfReexport + "\n"
 console.log("")
 if (isIndex) {
-  console.log(`Plan: rename ${basename}.ts → ${implName}.ts, create new index.ts barrel`)
+  console.log(`Plan: rename index.ts → ${implName}.ts, add self-reexport`)
 } else {
-  console.log(`Plan: rewrite ${basename}.ts in place, create index.ts barrel`)
+  console.log(`Plan: unwrap in place, add self-reexport`)
 }
 if (selfRefCount > 0) console.log(`Fixed ${selfRefCount} self-reference(s) (${nsName}.X → X)`)
 console.log("")
 if (dryRun) {
  console.log("")
  console.log("--- DRY RUN ---")
  console.log("")
-  console.log(`=== ${implName}.ts (first 30 lines) ===`)
+  console.log(`=== ${implName}.ts (first 20 lines) ===`)
  newContent
    .split("\n")
-    .slice(0, 30)
+    .slice(0, 20)
    .forEach((l, i) => console.log(`  ${i + 1}: ${l}`))
  console.log("  ...")
  console.log("")
-  console.log(`=== index.ts ===`)
+  console.log(`=== last 5 lines ===`)
-  console.log(`  ${barrelLine.trim()}`)
+  const allLines = newContent.split("\n")
  allLines.slice(-5).forEach((l, i) => console.log(`  ${allLines.length - 4 + i}: ${l}`))
  console.log("")
-  if (!isIndex) {
+  rewriteConsumers(nsName, implFile, implName, dir)
    const relDir = path.relative(path.resolve("src"), dir)
    console.log(`=== Import rewrites (would apply) ===`)
    console.log(`  ${relDir}/${basename}" → ${relDir}" across src/, test/, script/`)
  } else {
    console.log("No import rewrites needed (was index.ts)")
  }
 } else {
  if (isIndex) {
    fs.writeFileSync(implFile, newContent)
-    fs.writeFileSync(indexFile, barrelLine)
+    fs.unlinkSync(absPath)
-    console.log(`Wrote ${implName}.ts (${newContent.split("\n").length} lines)`)
+    console.log(`Renamed to ${implName}.ts (${newContent.split("\n").length} lines)`)
    console.log(`Wrote index.ts (barrel)`)
  } else {
    fs.writeFileSync(absPath, newContent)
    if (fs.existsSync(indexFile)) {
      const existing = fs.readFileSync(indexFile, "utf-8")
      if (!existing.includes(`export * as ${nsName}`)) {
        fs.appendFileSync(indexFile, barrelLine)
        console.log(`Appended to existing index.ts`)
      } else {
        console.log(`index.ts already has ${nsName} export`)
      }
    } else {
      fs.writeFileSync(indexFile, barrelLine)
      console.log(`Wrote index.ts (barrel)`)
    }
    console.log(`Rewrote ${basename}.ts (${newContent.split("\n").length} lines)`)
  }
-
+  rewriteConsumers(nsName, implFile, implName, dir)
  // --- Rewrite import paths across src/, test/, script/ ---
  const relDir = path.relative(path.resolve("src"), dir)
  if (!isIndex) {
    const oldTail = `${relDir}/${basename}`
    const searchDirs = ["src", "test", "script"].filter((d) => fs.existsSync(d))
    const rgResult = Bun.spawnSync(["rg", "-l", `from.*${oldTail}"`, ...searchDirs], {
      stdout: "pipe",
      stderr: "pipe",
    })
    const filesToRewrite = rgResult.stdout
      .toString()
      .trim()
      .split("\n")
      .filter((f) => f.length > 0)
    if (filesToRewrite.length > 0) {
      console.log(`\nRewriting imports in ${filesToRewrite.length} file(s)...`)
      for (const file of filesToRewrite) {
        const content = fs.readFileSync(file, "utf-8")
        fs.writeFileSync(file, content.replaceAll(`${oldTail}"`, `${relDir}"`))
      }
      console.log(`  Done: ${oldTail}" → ${relDir}"`)
    } else {
      console.log("\nNo import rewrites needed")
    }
  } else {
    console.log("\nNo import rewrites needed (was index.ts)")
  }
  // --- Fix sibling imports within the same directory ---
  const siblingFiles = fs.readdirSync(dir).filter((f) => {
    if (!f.endsWith(".ts")) return false
    if (f === "index.ts" || f === `${implName}.ts`) return false
    return true
  })
  let siblingFixCount = 0
  for (const sibFile of siblingFiles) {
    const sibPath = path.join(dir, sibFile)
    const content = fs.readFileSync(sibPath, "utf-8")
    const pattern = new RegExp(`from\\s+["']\\./${basename}["']`, "g")
    if (pattern.test(content)) {
      fs.writeFileSync(sibPath, content.replace(pattern, `from "."`))
      siblingFixCount++
    }
  }
  if (siblingFixCount > 0) {
    console.log(`Fixed ${siblingFixCount} sibling import(s) in ${path.basename(dir)}/ (./${basename} → .)`)
  }
 }
-console.log("")
+// ---------------------------------------------------------------------------
-console.log("=== Verify ===")
+// Consumer import rewriting (shared by default + retrofit mode)
-console.log("")
+// ---------------------------------------------------------------------------
-console.log("bunx --bun tsgo --noEmit   # typecheck")
+
-console.log("bun run test               # run tests")
+function rewriteConsumers(nsName: string, implFile: string, implName: string, dir: string) {
  const relImplFromSrc = path.relative(srcRoot, implFile).replace(/\.ts$/, "")
  const barrelMap = parseBarrelMap(path.join(dir, "index.ts"))
  // Find all files that reference the namespace name
  const searchDirs = ["src", "test", "script"].filter((d) => fs.existsSync(d))
  const rgResult = Bun.spawnSync(["rg", "-l", nsName, ...searchDirs, "--type", "ts"], {
    stdout: "pipe",
    stderr: "pipe",
  })
  const candidates = rgResult.stdout
    .toString()
    .trim()
    .split("\n")
    .filter((f) => f.length > 0)
  let totalChanges = 0
  const changedFiles: string[] = []
  for (const file of candidates) {
    const absFile = path.resolve(file)
    if (absFile === path.resolve(implFile) || absFile === path.resolve(absPath)) continue
    let content = fs.readFileSync(file, "utf-8")
    let changes = 0
    // Match: import { Foo } or import { Foo, Bar } or import type { Foo }
    const importRe = /^(import\s+(?:type\s+)?)\{\s*([^}]+)\}\s*from\s*["']([^"']+)["']/gm
    content = content.replace(importRe, (original, prefix: string, names: string, importPath: string) => {
      const nameList = names
        .split(",")
        .map((n) => n.trim())
        .filter(Boolean)
      // Check if this namespace is among the imported names
      const nsEntry = nameList.find((n) => n.split(/\s+as\s+/)[0].trim() === nsName)
      if (!nsEntry) return original
      // Check if this import resolves to our directory (barrel) or our file
      const resolved = resolveImportPath(importPath, file)
      if (!resolved) return original
      const resolvedAbs = path.resolve(resolved)
      const isBarrelImport =
        resolvedAbs === dir || resolvedAbs === path.join(dir, "index.ts") || resolvedAbs === path.join(dir, "index")
      const isDirectImport = resolvedAbs === implFile.replace(/\.ts$/, "") || resolvedAbs === implFile
      if (!isBarrelImport && !isDirectImport) return original
      // If it's already a direct import with just this name, nothing to change
      if (isDirectImport && nameList.length === 1) return original
      // Build the correct import path for the impl file
      const newImportPath = computeImportPath(file, implFile)
      if (nameList.length === 1) {
        // Simple: just repoint to the file
        changes++
        return `${prefix}{ ${nsEntry} } from "${newImportPath}"`
      }
      // Multi-import: split into separate lines
      const newLines: string[] = []
      for (const n of nameList) {
        const imported = n.split(/\s+as\s+/)[0].trim()
        if (imported === nsName) {
          newLines.push(`${prefix}{ ${n} } from "${newImportPath}"`)
          changes++
        } else if (barrelMap[imported]) {
          // Another namespace from the same barrel
          const otherFile = path.join(dir, barrelMap[imported] + ".ts")
          const otherPath = computeImportPath(file, otherFile)
          newLines.push(`${prefix}{ ${n} } from "${otherPath}"`)
          changes++
        } else {
          // Unknown — keep original path
          newLines.push(`${prefix}{ ${n} } from "${importPath}"`)
        }
      }
      return newLines.join("\n")
    })
    // Fix dynamic imports: const { Foo } = await import("...")
    const dynRe = new RegExp(
      `(const|let|var)\\s+\\{\\s*${nsName}\\s*\\}\\s*=\\s*await\\s+import\\(\\s*["']([^"']+)["']\\s*\\)`,
      "g",
    )
    content = content.replace(dynRe, (original, decl, importPath) => {
      const resolved = resolveImportPath(importPath, file)
      if (!resolved) return original
      const resolvedAbs = path.resolve(resolved)
      const isTarget =
        resolvedAbs === dir ||
        resolvedAbs === path.join(dir, "index.ts") ||
        resolvedAbs === path.join(dir, "index") ||
        resolvedAbs === implFile.replace(/\.ts$/, "") ||
        resolvedAbs === implFile
      if (!isTarget) return original
      const newPath = computeImportPath(file, implFile)
      changes++
      return `${decl} ${nsName} = await import("${newPath}")`
    })
    if (changes > 0) {
      if (!dryRun) fs.writeFileSync(file, content)
      changedFiles.push(file)
      totalChanges += changes
    }
  }
  console.log("")
  if (totalChanges > 0) {
    console.log(`${dryRun ? "Would rewrite" : "Rewrote"} ${totalChanges} import(s) in ${changedFiles.length} file(s):`)
    for (const f of changedFiles) console.log(`  ${f}`)
  } else {
    console.log("No import rewrites needed")
  }
  console.log("")
  console.log("=== Verify ===")
  console.log("")
  console.log("bunx --bun tsgo --noEmit                                # typecheck")
  console.log("bun run --conditions=browser ./src/index.ts generate    # circular import check")
 }
 // ---------------------------------------------------------------------------
 // Path utilities
 // ---------------------------------------------------------------------------
 function resolveImportPath(importPath: string, fromFile: string): string | null {
  if (importPath.startsWith("@/")) return path.join(srcRoot, importPath.slice(2))
  if (importPath.startsWith(".")) return path.resolve(path.dirname(fromFile), importPath)
  return null
 }
 function computeImportPath(fromFile: string, toFile: string): string {
  const fromAbs = path.resolve(fromFile)
  if (fromAbs.startsWith(srcRoot + "/")) {
    return `@/${path.relative(srcRoot, toFile).replace(/\.ts$/, "")}`
  }
  let rel = path.relative(path.dirname(fromAbs), toFile).replace(/\.ts$/, "")
  if (!rel.startsWith(".")) rel = "./" + rel
  return rel
 }
--- a/packages/opencode/specs/effect/namespace-treeshake.md
+++ b/packages/opencode/specs/effect/namespace-treeshake.md
@ -1,499 +1,161 @@
-# Namespace → flat export migration
+# Namespace → self-reexport migration
-Migrate `export namespace` to the `export * as` / flat-export pattern used by
+Migrate `export namespace` to flat module exports with a self-referential
-effect-smol. Primary goal: tree-shakeability. Secondary: consistency with Effect
+`export * as` at the bottom of each file. No barrel files.
 conventions, LLM-friendliness for future migrations.
-## What changes and what doesn't
+## The pattern
-The **consumer API stays the same**. You still write `Provider.ModelNotFoundError`,
+Each module file has flat exports plus one line at the bottom that re-exports
-`Config.JsonError`, `Bus.publish`, etc. The namespace ergonomics are preserved.
+itself as a namespace:
 What changes is **how** the namespace is constructed — the TypeScript
 `export namespace` keyword is replaced by `export * as` in a barrel file. This
 is a mechanical change: unwrap the namespace body into flat exports, add a
 one-line barrel. Consumers that import `{ Provider }` don't notice.
 Import paths actually get **nicer**. Today most consumers import from the
 explicit file (`"../provider/provider"`). After the migration, each module has a
 barrel `index.ts`, so imports become `"../provider"` or `"@/provider"`:
 ```ts
-// BEFORE — points at the file directly
+// config/config.ts
-import { Provider } from "../provider/provider"
+import { Log } from "../util/log"
-// AFTER — resolves to provider/index.ts, same Provider namespace
+export interface Info { model: string }
-import { Provider } from "../provider"
+export function load(): Info { ... }
 export const JsonError = NamedError.create(...)
 // Self-reexport: creates a named `Config` export that consumers can import
 export * as Config from "./config"
 ```
-## Why this matters right now
+Consumers import the namespace by name — editors auto-import this like any
-
+named export:
 The CLI binary startup time (TOI) is too slow. Profiling shows we're loading
 massive dependency graphs that are never actually used at runtime — because
 bundlers cannot tree-shake TypeScript `export namespace` bodies.
 ### The problem in one sentence
 `cli/error.ts` needs 6 lightweight `.isInstance()` checks on error classes, but
 importing `{ Provider }` from `provider.ts` forces the bundler to include **all
 20+ `@ai-sdk/*` packages**, `@aws-sdk/credential-providers`,
 `google-auth-library`, and every other top-level import in that 1709-line file.
 ### Why `export namespace` defeats tree-shaking
 TypeScript compiles `export namespace Foo { ... }` to an IIFE:
 ```js
 // TypeScript output
 export var Provider;
 (function (Provider) {
  Provider.ModelNotFoundError = NamedError.create(...)
  // ... 1600 more lines of assignments ...
 })(Provider || (Provider = {}))
 ```
 This is **opaque to static analysis**. The bundler sees one big function call
 whose return value populates an object. It cannot determine which properties are
 used downstream, so it keeps everything. Every `import` statement at the top of
 `provider.ts` executes unconditionally — that's 20+ AI SDK packages loaded into
 memory just so the CLI can check `Provider.ModelNotFoundError.isInstance(x)`.
 ### What `export * as` does differently
 `export * as Provider from "./provider"` compiles to a static re-export. The
 bundler knows the exact shape of `Provider` at compile time — it's the named
 export list of `./provider.ts`. When it sees `Provider.ModelNotFoundError` used
 but `Provider.layer` unused, it can trace that `ModelNotFoundError` doesn't
 reference `createAnthropic` or any AI SDK import, and drop them. The namespace
 object still exists at runtime — same API — but the bundler can see inside it.
 ### Concrete impact
 The worst import chain in the codebase:
 ```
 src/index.ts (entry point)
  └── FormatError from src/cli/error.ts
        ├── { Provider } from provider/provider.ts     (1709 lines)
        │     ├── 20+ @ai-sdk/* packages
        │     ├── @aws-sdk/credential-providers
        │     ├── google-auth-library
        │     ├── gitlab-ai-provider, venice-ai-sdk-provider
        │     └── fuzzysort, remeda, etc.
        ├── { Config } from config/config.ts           (1663 lines)
        │     ├── jsonc-parser
        │     ├── LSPServer (all server definitions)
        │     └── Plugin, Auth, Env, Account, etc.
        └── { MCP } from mcp/index.ts                  (930 lines)
              ├── @modelcontextprotocol/sdk (3 transports)
              └── open (browser launcher)
 ```
 All of this gets pulled in to check `.isInstance()` on 6 error classes — code
 that needs maybe 200 bytes total. This inflates the binary, increases startup
 memory, and slows down initial module evaluation.
 ### Why this also hurts memory
 Every module-level import is eagerly evaluated. Even with Bun's fast module
 loader, evaluating 20+ AI SDK factory functions, the AWS credential chain, and
 Google's auth library allocates objects, closures, and prototype chains that
 persist for the lifetime of the process. Most CLI commands never use a provider
 at all.
 ## What effect-smol does
 effect-smol achieves tree-shakeable namespaced APIs via three structural choices.
 ### 1. Each module is a separate file with flat named exports
 ```ts
-// Effect.ts — no namespace wrapper, just flat exports
+import { Config } from "../config/config"
-export const gen: { ... } = internal.gen
+Config.load()
-export const fail: <E>(error: E) => Effect<never, E> = internal.fail
+Config.JsonError.isInstance(x)
 export const succeed: <A>(value: A) => Effect<A> = internal.succeed
 // ... 230+ individual named exports
 ```
-### 2. Barrel file uses `export * as` (not `export namespace`)
+## Why this pattern
-```ts
+We tested every option with Bun. Three things matter: tree-shaking, circular
-// index.ts
+imports, and editor autocomplete.
 export * as Effect from "./Effect.ts"
 export * as Schema from "./Schema.ts"
 export * as Stream from "./Stream.ts"
 // ~134 modules
 ```
 This creates a namespace-like API (`Effect.gen`, `Schema.parse`) but the
 bundler knows the **exact shape** at compile time — it's the static export list
 of that file. It can trace property accesses (`Effect.gen` → keep `gen`,
 drop `timeout` if unused). With `export namespace`, the IIFE is opaque and
 nothing can be dropped.
 ### 3. `sideEffects: []` and deep imports
 ```jsonc
 // package.json
 { "sideEffects": [] }
 ```
 Plus `"./*": "./src/*.ts"` in the exports map, enabling
 `import * as Effect from "effect/Effect"` to bypass the barrel entirely.
 ### 4. Errors as flat exports, not class declarations
 ```ts
 // Cause.ts
 export const NoSuchElementErrorTypeId = core.NoSuchElementErrorTypeId
 export interface NoSuchElementError extends YieldableError { ... }
 export const NoSuchElementError: new(msg?: string) => NoSuchElementError = core.NoSuchElementError
 export const isNoSuchElementError: (u: unknown) => u is NoSuchElementError = core.isNoSuchElementError
 ```
 Each error is 4 independent exports: TypeId, interface, constructor (as const),
 type guard. All individually shakeable.
 ## The plan
 The core migration is **Phase 1** — convert `export namespace` to
 `export * as`. Once that's done, the bundler can tree-shake individual exports
 within each module. You do NOT need to break things into subfiles for
 tree-shaking to work — the bundler traces which exports you actually access on
 the namespace object and drops the rest, including their transitive imports.
 Splitting errors/schemas into separate files (Phase 0) is optional — it's a
 lower-risk warmup step that can be done before or after the main conversion, and
 it provides extra resilience against bundler edge cases. But the big win comes
 from Phase 1.
 ### Phase 0 (optional): Pre-split errors into subfiles
 This is a low-risk warmup that provides immediate benefit even before the full
 `export * as` conversion. It's optional because Phase 1 alone is sufficient for
 tree-shaking. But it's a good starting point if you want incremental progress:
 **For each namespace that defines errors** (15 files, ~30 error classes total):
 1. Create a sibling `errors.ts` file (e.g. `provider/errors.ts`) with the error
   definitions as top-level named exports:
   ```ts
   // provider/errors.ts
   import z from "zod"
   import { NamedError } from "@opencode-ai/shared/util/error"
   import { ProviderID, ModelID } from "./schema"
   export const ModelNotFoundError = NamedError.create(
     "ProviderModelNotFoundError",
     z.object({
       providerID: ProviderID.zod,
       modelID: ModelID.zod,
       suggestions: z.array(z.string()).optional(),
     }),
   )
   export const InitError = NamedError.create("ProviderInitError", z.object({ providerID: ProviderID.zod }))
   ```
 2. In the namespace file, re-export from the errors file to maintain backward
   compatibility:
   ```ts
   // provider/provider.ts — inside the namespace
   export { ModelNotFoundError, InitError } from "./errors"
   ```
 3. Update `cli/error.ts` (and any other light consumers) to import directly:
   ```ts
   // BEFORE
   import { Provider } from "../provider/provider"
   Provider.ModelNotFoundError.isInstance(input)
   // AFTER
   import { ModelNotFoundError as ProviderModelNotFoundError } from "../provider/errors"
   ProviderModelNotFoundError.isInstance(input)
   ```
 **Files to split (Phase 0):**
 | Current file            | New errors file                 | Errors to extract                                                                                                       |
 | ----------------------- | ------------------------------- | ----------------------------------------------------------------------------------------------------------------------- |
 | `provider/provider.ts`  | `provider/errors.ts`            | ModelNotFoundError, InitError                                                                                           |
 | `provider/auth.ts`      | `provider/auth-errors.ts`       | OauthMissing, OauthCodeMissing, OauthCallbackFailed, ValidationFailed                                                   |
 | `config/config.ts`      | (already has `config/paths.ts`) | ConfigDirectoryTypoError → move to paths.ts                                                                             |
 | `config/markdown.ts`    | `config/markdown-errors.ts`     | FrontmatterError                                                                                                        |
 | `mcp/index.ts`          | `mcp/errors.ts`                 | Failed                                                                                                                  |
 | `session/message-v2.ts` | `session/message-errors.ts`     | OutputLengthError, AbortedError, StructuredOutputError, AuthError, APIError, ContextOverflowError                       |
 | `session/message.ts`    | (shares with message-v2)        | OutputLengthError, AuthError                                                                                            |
 | `cli/ui.ts`             | `cli/ui-errors.ts`              | CancelledError                                                                                                          |
 | `skill/index.ts`        | `skill/errors.ts`               | InvalidError, NameMismatchError                                                                                         |
 | `worktree/index.ts`     | `worktree/errors.ts`            | NotGitError, NameGenerationFailedError, CreateFailedError, StartCommandFailedError, RemoveFailedError, ResetFailedError |
 | `storage/storage.ts`    | `storage/errors.ts`             | NotFoundError                                                                                                           |
 | `npm/index.ts`          | `npm/errors.ts`                 | InstallFailedError                                                                                                      |
 | `ide/index.ts`          | `ide/errors.ts`                 | AlreadyInstalledError, InstallFailedError                                                                               |
 | `lsp/client.ts`         | `lsp/errors.ts`                 | InitializeError                                                                                                         |
 ### Phase 1: The real migration — `export namespace` → `export * as`
 This is the phase that actually fixes tree-shaking. For each module:
 1. **Unwrap** the `export namespace Foo { ... }` — remove the namespace wrapper,
   keep all the members as top-level `export const` / `export function` / etc.
 2. **Rename** the file if it's currently `index.ts` (e.g. `bus/index.ts` →
   `bus/bus.ts`), so the barrel can take `index.ts`.
 3. **Create the barrel** `index.ts` with one line: `export * as Foo from "./foo"`
 The file structure change for a module that's currently a single file:
 ```
-# BEFORE
+A. Barrel (export * as Foo + Bar from index.ts)
-provider/
+   Runtime:  foo LOADED even though only Bar used  ❌
-  provider.ts        ← 1709-line file with `export namespace Provider { ... }`
+   Bundled:  foo LOADED if it has side effects     ❌
   Autocomplete: works (named export from barrel)
-# AFTER
+B. import * as Bar from "./bar" (direct, no barrel)
-provider/
+   Runtime:  only bar loaded                       ✅
-  index.ts           ← NEW: `export * as Provider from "./provider"`
+   Bundled:  only bar loaded                       ✅
-  provider.ts        ← SAME file, same name, just unwrap the namespace
+   Autocomplete: broken (editors can't auto-import) ❌
 C. Self-reexport: export * as Bar from "./bar" inside bar.ts
   Runtime:  only bar loaded                       ✅
   Bundled:  only bar loaded                       ✅
   Autocomplete: works (named export from file)    ✅
 ```
-And the code change is purely removing the wrapper:
+The self-reexport gives us tree-shaking + autocomplete + no barrels.
-```ts
+### Bundle overhead
 // BEFORE: provider/provider.ts
 export namespace Provider {
  export class Service extends Context.Service<...>()("@opencode/Provider") {}
  export const layer = Layer.effect(Service, ...)
  export const ModelNotFoundError = NamedError.create(...)
  export function parseModel(model: string) { ... }
 }
-// AFTER: provider/provider.ts — identical exports, no namespace keyword
+The self-reexport adds ~240 bytes per module (an `Object.defineProperty`
-export class Service extends Context.Service<...>()("@opencode/Provider") {}
+wrapper). At 100 modules that's ~24KB — irrelevant for a CLI binary.
 export const layer = Layer.effect(Service, ...)
 export const ModelNotFoundError = NamedError.create(...)
 export function parseModel(model: string) { ... }
 ```
-```ts
+### The `Foo.Foo.Foo` thing
 // NEW: provider/index.ts
 export * as Provider from "./provider"
 ```
-Consumer code barely changes — import path gets shorter:
+`Config.Config.Config.load()` compiles and runs. It's a harmless side effect
 of self-referential modules. Nobody would write it.
-```ts
+## Why barrel files don't work
 // BEFORE
 import { Provider } from "../provider/provider"
-// AFTER — resolves to provider/index.ts, same Provider object
+Barrel files (`index.ts` with `export * as`) have two problems:
 import { Provider } from "../provider"
 ```
-All access like `Provider.ModelNotFoundError`, `Provider.Service`,
+1. **Bun loads all re-exported modules** when you import through a barrel,
-`Provider.layer` works exactly as before. The difference is invisible to
+   even if you only use one. This happens at both runtime and bundle time
-consumers but lets the bundler see inside the namespace.
+   for modules with side effects (which ours have — top-level imports).
-**Once this is done, you don't need to break anything into subfiles for
+2. **Circular import risk.** Sibling files can't import through their own
-tree-shaking.** The bundler traces that `Provider.ModelNotFoundError` only
+   barrel, and cross-directory barrel cycles cause runtime `ReferenceError`.
 depends on `NamedError` + `zod` + the schema file, and drops
 `Provider.layer` + all 20 AI SDK imports when they're unused. This works because
 `export * as` gives the bundler a static export list it can do inner-graph
 analysis on — it knows which exports reference which imports.
-**Order of conversion** (by risk / size, do small modules first):
+## The migration
-1. Tiny utilities: `Archive`, `Color`, `Token`, `Rpc`, `LocalContext` (~7-66 lines each)
+There are two tasks:
 2. Small services: `Auth`, `Env`, `BusEvent`, `SessionStatus`, `SessionRunState`, `Editor`, `Selection` (~25-91 lines)
 3. Medium services: `Bus`, `Format`, `FileTime`, `FileWatcher`, `Command`, `Question`, `Permission`, `Vcs`, `Project`
 4. Large services: `Config`, `Provider`, `MCP`, `Session`, `SessionProcessor`, `SessionPrompt`, `ACP`
-### Phase 2: Build configuration
+### Task 1: Convert remaining `export namespace` files (~50)
-After the module structure supports tree-shaking:
+For each file:
-1. Add `"sideEffects": []` to `packages/opencode/package.json` (or
+1. Remove the `export namespace Foo {` wrapper and closing `}`
-   `"sideEffects": false`) — this is safe because our services use explicit
+2. Dedent the body
-   layer composition, not import-time side effects.
+3. Add `export * as Foo from "./file"` at the bottom
-2. Verify Bun's bundler respects the new structure. If Bun's tree-shaking is
+4. Rewrite consumer imports: `import { Foo } from "..."` stays the same
-   insufficient, evaluate whether the compiled binary path needs an esbuild
+   if the path already points at the file. If it points at a barrel,
-   pre-pass.
+   change it to point at the file directly.
 3. Consider adding `/*#__PURE__*/` annotations to `NamedError.create(...)` calls
   — these are factory functions that return classes, and bundlers may not know
   they're side-effect-free without the annotation.
-## Automation
+### Task 2: Fix already-converted files (~32 barrel dirs)
-The transformation is scripted. From `packages/opencode`:
+These were converted in the earlier barrel-based migration. Each directory
 has an `index.ts` barrel and flat-exported source files. To migrate:
 1. Add `export * as Foo from "./file"` to the bottom of each source file
 2. Change consumers from `import { Foo } from "../dir"` (barrel) to
   `import { Foo } from "../dir/file"` (direct)
 3. The barrel `index.ts` can be deleted or left in place (harmless once
   nothing imports through it)
 ### Automation
 ```bash
-bun script/unwrap-namespace.ts <file> [--dry-run]
+# Convert an unconverted namespace file:
 bun script/unwrap-namespace.ts src/session/session.ts --dry-run
 bun script/unwrap-namespace.ts src/session/session.ts
 # Retrofit an already-converted file (add self-reexport + fix consumers):
 bun script/unwrap-namespace.ts src/config/config.ts --retrofit --dry-run
 bun script/unwrap-namespace.ts src/config/config.ts --retrofit
 ```
-The script uses ast-grep for accurate AST-based namespace boundary detection
+The script handles both cases:
 (no false matches from braces in strings/templates/comments), then:
-1. Removes the `export namespace Foo {` line and its closing `}`
+- **Default mode**: unwraps namespace + adds self-reexport + rewrites imports
-2. Dedents the body by one indent level (2 spaces)
+- **Retrofit mode** (`--retrofit`): file already has flat exports, just adds
-3. If the file is `index.ts`, renames it to `<name>.ts` and creates a new
+  the self-reexport line and rewrites consumers from barrel to direct
   `index.ts` barrel
 4. If the file is NOT `index.ts`, rewrites it in place and creates `index.ts`
 5. Prints the exact commands to find and rewrite import paths
-### Walkthrough: converting a module
+### Verification
-Using `Provider` as an example:
+After any conversion:
 ```bash
-# 1. Preview what will change
+bunx --bun tsgo --noEmit                                # typecheck
-bun script/unwrap-namespace.ts src/provider/provider.ts --dry-run
+bun run --conditions=browser ./src/index.ts generate    # circular import check
 # 2. Apply the transformation
 bun script/unwrap-namespace.ts src/provider/provider.ts
 # 3. Rewrite import paths (script prints the exact command)
 rg -l 'from.*provider/provider' src/ | xargs sed -i '' 's|provider/provider"|provider"|g'
 # 4. Verify
 bun typecheck
 bun run test
 ```
 **What changes on disk:**
 ```
 # BEFORE
 provider/
  provider.ts        ← 1709 lines, `export namespace Provider { ... }`
 # AFTER
 provider/
  index.ts           ← NEW: `export * as Provider from "./provider"`
  provider.ts        ← same file, namespace unwrapped to flat exports
 ```
 **What changes in consumer code:**
 ```ts
 // BEFORE
 import { Provider } from "../provider/provider"
 // AFTER — shorter path, same Provider object
 import { Provider } from "../provider"
 ```
 All property access (`Provider.Service`, `Provider.ModelNotFoundError`, etc.)
 stays identical.
 ### Two cases the script handles
 **Case A: file is NOT `index.ts`** (e.g. `provider/provider.ts`)
 - Rewrites the file in place (unwrap + dedent)
 - Creates `provider/index.ts` as the barrel
 - Import paths change: `"../provider/provider"` → `"../provider"`
 **Case B: file IS `index.ts`** (e.g. `bus/index.ts`)
 - Renames `index.ts` → `bus.ts` (kebab-case of namespace name)
 - Creates new `index.ts` as the barrel
 - **No import rewrites needed** — `"@/bus"` already resolves to `bus/index.ts`
 ## Do I need to split errors/schemas into subfiles?
 **No.** Once you do the `export * as` conversion, the bundler can tree-shake
 individual exports within the file. If `cli/error.ts` only accesses
 `Provider.ModelNotFoundError`, the bundler traces that `ModelNotFoundError`
 doesn't reference `createAnthropic` and drops the AI SDK imports.
 Splitting into subfiles (errors.ts, schema.ts) is still a fine idea for **code
 organization** — smaller files are easier to read and review. But it's not
 required for tree-shaking. The `export * as` conversion alone is sufficient.
 The one case where subfile splitting provides extra tree-shake value is if an
 imported package has module-level side effects that the bundler can't prove are
 unused. In practice this is rare — most npm packages are side-effect-free — and
 adding `"sideEffects": []` to package.json handles the common cases.
 ## Scope
 | Metric                                          | Count           |
 | ----------------------------------------------- | --------------- |
 | Files with `export namespace`                   | 106             |
 | Total namespace declarations                    | 118 (12 nested) |
 | Files with `NamedError.create` inside namespace | 15              |
 | Total error classes to extract                  | ~30             |
 | Files using `export * as` today                 | 0               |
 Phase 1 (the `export * as` conversion) is the main change. It's mechanical and
 LLM-friendly but touches every import site, so it should be done module by
 module with type-checking between each step. Each module is an independent PR.
 ## Rules for new code
-Going forward:
+- **No `export namespace`.** Use flat named exports.
 - **No barrel `index.ts` for internal code.**
 - **Every module file gets a self-reexport** at the bottom:
  `export * as Foo from "./foo"`
 - **Consumers import the namespace by name:**
  `import { Foo } from "../path/to/foo"`
- **No new `export namespace`**. Use a file with flat named exports and
+## Remaining work
  `export * as` in the barrel.
 - Keep the service, layer, errors, schemas, and runtime wiring together in one
  file if you want — that's fine now. The `export * as` barrel makes everything
  individually shakeable regardless of file structure.
 - If a file grows large enough that it's hard to navigate, split by concern
  (errors.ts, schema.ts, etc.) for readability. Not for tree-shaking — the
  bundler handles that.
-## Circular import rules
+### Unconverted (~50 namespaces):
-Barrel files (`index.ts` with `export * as`) introduce circular import risks.
+**Session directory (14)** — deep cross-directory cycles currently via barrel:
 These cause `ReferenceError: Cannot access 'X' before initialization` at
 runtime — not caught by the type checker.
-### Rule 1: Sibling files never import through their own barrel
+- SessionRunState, SystemPrompt, Message, SessionRetry, SessionProcessor,
  SessionRevert, Instruction, SessionSummary, Todo, LLM, SessionStatus,
  SessionCompaction, SessionPrompt, MessageV2
-Files in the same directory must import directly from the source file, never
+**Special cases:**
 through `"."` or `"@/<own-dir>"`:
-```ts
+- `flag/flag.ts` — uses `Object.defineProperty(Flag, ...)`, needs restructuring
-// BAD — circular: index.ts re-exports both files, so A → index → B → index → A
+- `account/repo.ts` — ast-grep fails, needs manual conversion
-import { Sibling } from "."
+- `v2/` (multi-namespace files) — SessionEvent (5 nested), etc.
-// GOOD — direct, no cycle
+**Other standalone modules** (~30 across server/, cli/, plugin/, etc.)
 import * as Sibling from "./sibling"
 ```
-### Rule 2: Cross-directory imports must not form cycles through barrels
+### Already converted (32 barrel dirs) — need retrofit:
-If `src/lsp/lsp.ts` imports `Config` from `"../config"`, and
+config, provider, bus, mcp, effect, util, file, tool, storage, lsp,
-`src/config/config.ts` imports `LSPServer` from `"../lsp"`, that's a cycle:
+project, plugin, permission, skill, auth, env, worktree, ide, snapshot,
-
+installation, pty, share, cli/cmd/tui/util, plugin/github-copilot, etc.
 ```
 lsp/lsp.ts → config/index.ts → config/config.ts → lsp/index.ts → lsp/lsp.ts 💥
 ```
 Fix by importing the specific file, breaking the cycle:
 ```ts
 // In config/config.ts — import directly, not through the lsp barrel
 import * as LSPServer from "../lsp/server"
 ```
 ### Why the type checker doesn't catch this
 TypeScript resolves types lazily — it doesn't evaluate module-scope
 expressions. The `ReferenceError` only happens at runtime when a module-scope
 `const` or function call accesses a value from a circular dependency that
 hasn't finished initializing. The SDK build step (`bun run --conditions=browser
 ./src/index.ts generate`) is the reliable way to catch these because it
 evaluates all modules eagerly.
 ### How to verify
 After any namespace conversion, run:
 ```bash
 cd packages/opencode
 bun run --conditions=browser ./src/index.ts generate
 ```
 If this completes without `ReferenceError`, the module graph is safe.
Author	SHA1	Message	Date
Kit Langton	2bf5407657	refactor: drop namespace proof-of-concept code changes	2026-04-16 11:18:33 -04:00
Kit Langton	95f90ebfc8	refactor: migrate namespace tooling to self-reexport pattern	2026-04-16 11:17:10 -04:00