apple/pkl · error · PklException

Failed to write to $depsFile: ${e.message}

Error message

Failed to write to $depsFile: ${e.message}

What it means

Thrown by CliProjectResolver.doRun when writing the generated PklProjectDependencies file (PklProjectDependencies.pem deps file next to the PklProject) fails with an IOException. `pkl project resolve` computes the dependency graph and persists it to disk; if the file cannot be opened or written, the resolver wraps the IOException in a PklException with this message, which includes the deps file path and the underlying IOException message.

Source

Thrown at pkl-cli/src/main/kotlin/org/pkl/cli/CliProjectResolver.kt:56

        PackageResolver.getInstance(
          SecurityManagers.standard(
            allowedModules,
            allowedResources,
            SecurityManagers.defaultTrustLevels,
            rootDir,
          ),
          httpClient,
          moduleCacheDir,
        )
      val dependencies = ProjectDependenciesResolver(project, packageResolver, errWriter).resolve()
      val depsFile =
        projectFile.parent.resolve(ProjectDependenciesManager.PKL_PROJECT_DEPS_FILENAME).toFile()
      try {
        depsFile.outputStream().use { dependencies.writeTo(it) }
        consoleWriter.appendLine(depsFile.toString())
        consoleWriter.flush()
      } catch (e: IOException) {
        throw PklException("Failed to write to $depsFile: ${e.message}", e)
      }
    }
  }
}

View on GitHub (pinned to f3efcbfc9b)

Solutions

1. Check and fix write permissions on the project directory and any existing PklProjectDependencies file (e.g. chmod/chown)
2. Remove the stale deps file if it is owned by another user or immutable
3. Ensure the filesystem is writable (not mounted read-only) and has free disk space
4. Re-run `pkl project resolve`

try { resolveProject() } catch (PklException e) { if (e.getMessage().startsWith("Failed to write to")) handleUnwritableDepsFile(); else throw e; }

When it happens

Trigger: Running `pkl project resolve` when the target deps file cannot be written: read-only filesystem or directory, missing write permissions, the path is a directory instead of a file, or disk full.

Common situations: Running inside a read-only container or CI workspace; file owned by another user after running as root earlier; the project directory was made immutable; NFS/permissions issues in shared dev environments.

Understand the failure class

Background: "failed to write file", "Could not save figure", "Error saving remote file" — file write failed: causes and fixes across languages and libraries — this error's family across 38 libraries.

Related errors

• ioErrorWritingTestOutputFile
• ioErrorReadingTestOutputFile
• ioErrorLoadingModule
• ioErrorLoadingModule
• I/O error writing file `$outputFile`. Cause: ${e.message}

AI-assisted analysis of apple/pkl@f3efcbfc9b (2026-09-08). Data as JSON: /api/errors/b9ead56b29506cc1. Report an issue: GitHub.