map POSIX errno to actionable IPC error kinds (T-79)

pane.spawn (via PtyException.errno) and editor.open (via FileSystemException.osError.errorCode) now route ENOENT to not_found, EACCES/EPERM to user_error with a permissions hint, EISDIR/ENOTDIR/EEXIST to distinct user-error/conflict, and EMFILE/ENFILE to tool_error with a "fd limit hit" hint. The mapping lives in lib/src/ipc/errno_mapping.dart so other handlers can adopt the same surface as they pick up errno-bearing failures. Co-Authored-By: Claude <noreply@anthropic.com>
2026-05-06 09:56:04 +02:00
parent 41fd586ca0
commit 5fb3df84ed
6 changed files with 224 additions and 5 deletions
@@ -0,0 +1,103 @@
+/// Map POSIX errno values to IPC error envelopes with actionable
+/// messages. Used by command handlers that wrap syscall-backed work
+/// (PTY spawn, file open) so the client can distinguish "binary not
+/// found" from "permission denied" from "system limit hit" instead
+/// of seeing the same generic `tool_error: foo failed`.
+library;
+
+import 'envelope.dart';
+import 'schema_v1.dart';
+
+/// Selected POSIX errno values we map specially. Others fall through
+/// to a generic toolError. Values match Linux glibc and macOS Darwin
+/// (the two platforms that share the same numbers for these entries).
+abstract class PosixErrno {
+  static const int eperm = 1;
+  static const int enoent = 2;
+  static const int esrch = 3;
+  static const int eio = 5;
+  static const int ebadf = 9;
+  static const int eagain = 11;
+  static const int enomem = 12;
+  static const int eacces = 13;
+  static const int eexist = 17;
+  static const int enotdir = 20;
+  static const int eisdir = 21;
+  static const int emfile = 24;
+  static const int enfile = 23;
+  static const int epipe = 32;
+}
+
+/// Build an [IpcError] from a POSIX [errno] for an operation [op]
+/// (e.g. `pane.spawn`, `editor.open`) on optional [target] (a path,
+/// command name, etc.). The returned error uses `notFound`,
+/// `userError`, or `toolError` based on what's actionable.
+IpcError errnoToIpcError({
+  required int errno,
+  required String op,
+  String? target,
+  String? raw,
+}) {
+  final what = target != null ? ' ($target)' : '';
+  switch (errno) {
+    case PosixErrno.enoent:
+      return IpcError(
+        code: IpcExitCode.notFound,
+        kind: IpcErrorKind.notFound,
+        message: '$op: not found$what',
+      );
+    case PosixErrno.eacces:
+    case PosixErrno.eperm:
+      return IpcError(
+        code: IpcExitCode.userError,
+        kind: IpcErrorKind.userError,
+        message: '$op: permission denied$what',
+        hint: 'check file permissions or run with appropriate access',
+      );
+    case PosixErrno.eisdir:
+      return IpcError(
+        code: IpcExitCode.userError,
+        kind: IpcErrorKind.userError,
+        message: '$op: is a directory$what',
+      );
+    case PosixErrno.enotdir:
+      return IpcError(
+        code: IpcExitCode.userError,
+        kind: IpcErrorKind.userError,
+        message: '$op: not a directory$what',
+      );
+    case PosixErrno.eexist:
+      return IpcError(
+        code: IpcExitCode.conflict,
+        kind: IpcErrorKind.conflict,
+        message: '$op: already exists$what',
+      );
+    case PosixErrno.emfile:
+    case PosixErrno.enfile:
+      return IpcError(
+        code: IpcExitCode.toolError,
+        kind: IpcErrorKind.toolError,
+        message: '$op: too many open files',
+        hint: 'system or per-process file descriptor limit reached',
+      );
+    case PosixErrno.enomem:
+      return IpcError(
+        code: IpcExitCode.toolError,
+        kind: IpcErrorKind.toolError,
+        message: '$op: out of memory',
+      );
+    case PosixErrno.eagain:
+      return IpcError(
+        code: IpcExitCode.toolError,
+        kind: IpcErrorKind.toolError,
+        message: '$op: resource temporarily unavailable',
+        hint: 'retry may succeed',
+      );
+    default:
+      return IpcError(
+        code: IpcExitCode.toolError,
+        kind: IpcErrorKind.toolError,
+        message: '$op failed${raw != null ? ': $raw' : ' (errno=$errno)'}',
+      );
+  }
+}