tauri-apps/tauri · error

unable to autogenerate default permissions

Error message

unable to autogenerate default permissions

What it means

During a plugin/app build, `define_permissions` autogenerates a `default.toml` permission file by writing it with `write_if_changed`. If the write fails, the build script panics. This is a filesystem failure while materializing autogenerated ACL permission files.

Solutions

1. Check filesystem permissions on the crate's `permissions/` directory and make it writable for the build user.
2. Ensure no other process (editor, antivirus, another cargo build) holds the default.toml file locked.
3. Verify free disk space and that the build directory is not mounted read-only.
4. Restore the `permissions/autogenerated` directory if it was deleted (git checkout / rebuild).

Example fix

// before
chmod -w permissions/autogenerated
// after
chmod -R u+w permissions/ && cargo build

# ensure permissions dir is writable before build
[ -w permissions/autogenerated ] || chmod -R u+w permissions/

When it happens

Trigger: `define_permissions` calls `write_if_changed(autogenerated/default.toml, default_toml)`; the write fails because the `permissions/autogenerated` directory is read-only, missing (creation failed earlier), the path is invalid, or the disk is full.

Common situations: Read-only source checkout or CI workspace; files locked by an editor/antivirus on Windows; building from a package manager cache with a read-only crate directory; disk quota exceeded.

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

• Permission not found, expected one of
• unable to autogenerate core:default set
• unable to autogenerate
• unable to create autogenerated commands dir
• Couldn't find capabilities directory at

AI-assisted analysis of tauri-apps/tauri@460ec35447 (2026-09-18). Data as JSON: /api/errors/3b64ba6f387d1f2e. Report an issue: GitHub.

Appendix: source

Thrown at crates/tauri/build.rs:409

    let all_enable_by_default = if all_commands_enabled_by_default {
      ", which enables all commands"
    } else {
      ""
    };

    let default_toml = format!(
      r#"{LICENSE_HEADER}# Automatically generated - DO NOT EDIT!

[default]
description = "Default permissions for the plugin{all_enable_by_default}."
permissions = [{default_permissions}]
"#,
    );

    let out_path = autogenerated.join("default.toml");
    write_if_changed(out_path, default_toml)
      .unwrap_or_else(|_| panic!("unable to autogenerate default permissions"));

    let permissions = tauri_utils::acl::build::define_permissions(
      &PathBuf::from(glob::Pattern::escape(
        &permissions_out_dir.to_string_lossy(),
      ))
      .join("**")
      .join("*.toml")
      .to_string_lossy(),
      &format!("tauri:{plugin}"),
      out_dir,
      |_| true,
    )
    .unwrap_or_else(|e| panic!("failed to define permissions for {plugin}: {e}"));

    let docs_out_dir = Path::new("permissions")
      .join(plugin_directory_name)
      .join("autogenerated");
    fs::create_dir_all(&docs_out_dir).expect("failed to create plugin documentation directory");

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