From 13ac849db5c378ed04d02d644006f01e70db31b6 Mon Sep 17 00:00:00 2001
From: Kit Langton <kit.langton@gmail.com>
Date: Sun, 3 May 2026 11:21:34 -0400
Subject: refactor(config+core): drop ConfigPaths.readFile, add
 AppFileSystem.readFileStringSafe, flatten TuiConfig.loadState (#25602)

---
 packages/core/src/filesystem.ts                  |  8 +++++++
 packages/core/test/filesystem/filesystem.test.ts | 28 ++++++++++++++++++++++++
 2 files changed, 36 insertions(+)

(limited to 'packages/core')

diff --git a/packages/core/src/filesystem.ts b/packages/core/src/filesystem.ts
index 44346be8f..8a1cc3a08 100644
--- a/packages/core/src/filesystem.ts
+++ b/packages/core/src/filesystem.ts
@@ -24,6 +24,7 @@ export namespace AppFileSystem {
     readonly isDir: (path: string) => Effect.Effect<boolean>
     readonly isFile: (path: string) => Effect.Effect<boolean>
     readonly existsSafe: (path: string) => Effect.Effect<boolean>
+    readonly readFileStringSafe: (path: string) => Effect.Effect<string | undefined, Error>
     readonly readJson: (path: string) => Effect.Effect<unknown, Error>
     readonly writeJson: (path: string, data: unknown, mode?: number) => Effect.Effect<void, Error>
     readonly ensureDir: (path: string) => Effect.Effect<void, Error>
@@ -47,6 +48,12 @@ export namespace AppFileSystem {
         return yield* fs.exists(path).pipe(Effect.orElseSucceed(() => false))
       })
 
+      const readFileStringSafe = Effect.fn("FileSystem.readFileStringSafe")(function* (path: string) {
+        return yield* fs
+          .readFileString(path)
+          .pipe(Effect.catchReason("PlatformError", "NotFound", () => Effect.succeed(undefined)))
+      })
+
       const isDir = Effect.fn("FileSystem.isDir")(function* (path: string) {
         const info = yield* fs.stat(path).pipe(Effect.catch(() => Effect.void))
         return info?.type === "Directory"
@@ -163,6 +170,7 @@ export namespace AppFileSystem {
       return Service.of({
         ...fs,
         existsSafe,
+        readFileStringSafe,
         isDir,
         isFile,
         readDirectoryEntries,
diff --git a/packages/core/test/filesystem/filesystem.test.ts b/packages/core/test/filesystem/filesystem.test.ts
index b77f4e356..1d9405333 100644
--- a/packages/core/test/filesystem/filesystem.test.ts
+++ b/packages/core/test/filesystem/filesystem.test.ts
@@ -65,6 +65,34 @@ describe("AppFileSystem", () => {
     )
   })
 
+  describe("readFileStringSafe", () => {
+    it(
+      "returns file contents when file exists",
+      Effect.gen(function* () {
+        const fs = yield* AppFileSystem.Service
+        const filesys = yield* FileSystem.FileSystem
+        const tmp = yield* filesys.makeTempDirectoryScoped()
+        const file = path.join(tmp, "exists.txt")
+        yield* filesys.writeFileString(file, "hello")
+
+        const result = yield* fs.readFileStringSafe(file)
+        expect(result).toBe("hello")
+      }),
+    )
+
+    it(
+      "returns undefined for missing file (NotFound)",
+      Effect.gen(function* () {
+        const fs = yield* AppFileSystem.Service
+        const filesys = yield* FileSystem.FileSystem
+        const tmp = yield* filesys.makeTempDirectoryScoped()
+
+        const result = yield* fs.readFileStringSafe(path.join(tmp, "does-not-exist.txt"))
+        expect(result).toBeUndefined()
+      }),
+    )
+  })
+
   describe("readJson / writeJson", () => {
     it(
       "round-trips JSON data",
-- 
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