denoland/deno · error · SystemError

ERR_FS_CP_EEXIST

ERR_FS_CP_EEXIST

Error message

Target already exists

What it means

When fs.cp copies a file onto an existing destination, the native code consults the force and errorOnExist options (and the COPYFILE_EXCL mode): with force:false and errorOnExist:true (or an exclusive copy mode), an existing dest is rejected with kind EEXIST, mapped by throwCpError to ERR_FS_CP_EEXIST ('Target already exists', errno EEXIST). Without errorOnExist the copy would silently skip; this flag turns the skip into an explicit error.

Solutions

1. If overwriting is fine, set force: true (with errorOnExist removed/false) so dest is unlinked before the copy
2. If the conflict is real, catch the error and surface which path already exists (err.path)
3. Pre-check with fs.existsSync(dest) and branch to skip/overwrite explicitly instead of relying on the throw

Example fix

// before
fs.cp('app.tar', '/srv/app.tar', { errorOnExist: true }, cb); // dest exists

// after — allow overwrite
fs.cp('app.tar', '/srv/app.tar', { force: true }, cb);
// after — deliberate conflict handling
if (fs.existsSync('/srv/app.tar')) { /* skip or ask */ } else fs.cp('app.tar', '/srv/app.tar', cb);

if (opts.errorOnExist && fs.existsSync(dest)) { /* decide explicitly instead of letting cp throw */ }

try { await fs.promises.cp(src, dest, { errorOnExist: true, force: false }); } catch (e) { if (e.code === 'ERR_FS_CP_EEXIST') return { skipped: true, existing: e.path }; throw e; }

When it happens

Trigger: fs.cp(src, dest, { errorOnExist: true, force: false }, cb) with dest present; copying with fs.constants.COPYFILE_EXCL semantics where the dest already exists; CI pipelines asserting 'first deploy wins' by failing on any pre-existing artifact.

Common situations: Atomic installers that must not clobber a previous release; concurrent workers racing to create the same output file; re-running a generator that treats an existing output as a conflict instead of an overwrite.

Understand the failure class

Background: "already exists" / EEXIST / FileAlreadyExistsException: what the 'file already exists' error means and how to fix it — this error's family across 37 libraries.

Related errors

• ERR_FS_CP_DIR_TO_NON_DIR
• ERR_FS_CP_EINVAL
• ERR_FS_CP_FIFO_PIPE
• ERR_FS_CP_NON_DIR_TO_DIR
• ERR_FS_CP_SOCKET

AI-assisted analysis of denoland/deno@9ad36f7a2c (2026-08-20). Data as JSON: /api/errors/4b9114d3985fa25a. Report an issue: GitHub.

Appendix: source

Thrown at ext/node/polyfills/_fs/cp/cp.ts:84

      });
    case "DIR_TO_NON_DIR":
      throw new ERR_FS_CP_DIR_TO_NON_DIR({
        message: err.message,
        path: err.path,
        syscall: "cp",
        errno: EISDIR,
        code: "EISDIR",
      });
    case "NON_DIR_TO_DIR":
      throw new ERR_FS_CP_NON_DIR_TO_DIR({
        message: err.message,
        path: err.path,
        syscall: "cp",
        errno: ENOTDIR,
        code: "ENOTDIR",
      });
    case "EEXIST":
      throw new ERR_FS_CP_EEXIST({
        message: err.message,
        path: err.path,
        syscall: "cp",
        errno: EEXIST,
        code: "EEXIST",
      });
    case "EISDIR":
      throw new ERR_FS_EISDIR({
        message: err.message,
        path: err.path,
        syscall: "cp",
        errno: EISDIR,
        code: "EISDIR",
      });
    case "SOCKET":
      throw new ERR_FS_CP_SOCKET({
        message: err.message,
        path: err.path,

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