Tauri "Isolation" Pattern only supports relative or absolute

Error message

Tauri "Isolation" Pattern only supports relative or absolute (`/`) paths.

What it means

Same Isolation Pattern inlining logic as html.rs, implemented in the alternate HTML processing module (html2.rs): script src paths are resolved against the dist directory and rooted paths are normalized by stripping '/'. The expect fires when strip_prefix("/") fails, i.e. the path is rooted without starting with '/': Windows drive letters or UNC paths.

Source

Thrown at crates/tauri-utils/src/html2.rs:152

///
/// # Stability
///
/// This dependency [`dom_query`] for [`Document`] might receive updates in minor releases.
#[cfg(feature = "isolation")]
pub fn inline_isolation(document: &Document, dir: &std::path::Path) {
  let scripts = document.select("script[src]");

  for script in scripts.nodes() {
    let src = match script.attr("src") {
      Some(s) => s.to_string(),
      None => continue,
    };

    let mut path = std::path::PathBuf::from(src);
    if path.has_root() {
      path = path
        .strip_prefix("/")
        .expect("Tauri \"Isolation\" Pattern only supports relative or absolute (`/`) paths.")
        .into();
    }

    let file = std::fs::read_to_string(dir.join(path)).expect("unable to find isolation file");

    script.set_text(file);
    script.remove_attr("src");
  }
}

// TODO: Verify this, this is not found in the HTML spec, see https://github.com/tauri-apps/tauri/pull/14265#discussion_r2415396842
/// Normalize line endings in script content to match what the browser uses for CSP hashing.
///
/// According to the HTML spec, browsers normalize:
/// - `\r\n` → `\n`
/// - `\r`   → `\n`
pub fn normalize_script_for_csp(input: &[u8]) -> Vec<u8> {
  let mut output = Vec::with_capacity(input.len());

View on GitHub (pinned to 56d19c39e4)

Solutions

Use a src relative to the frontend dist directory.
Or use a URL-absolute path starting with a single '/'.
Remove any drive-letter or UNC path from script src attributes in the isolation HTML.

Example fix

<!-- before -->
<script src="D:\build\isolation.js"></script>

<!-- after -->
<script src="/isolation.js"></script>

Defensive patterns

Strategy: validation

Validate before calling

fn is_supported_isolation_src(src: &str) -> bool {
    let b = src.as_bytes();
    !(src.starts_with("\\\\") || (b.len() >= 2 && b[1] == b':'))
}

Prevention

Use relative or single-leading-slash src values in the isolation HTML.
Reject Windows absolute and UNC paths in code review of the isolation template.

When it happens

Trigger: Using the html2-based processing path with an isolation index.html containing <script src="C:\path\file.js"> or a UNC (\\server\share\file.js) src on Windows; Unix-style '/file.js' works.

Common situations: Windows development machines and CI; absolute local paths committed into the isolation template.

Related errors

AI-assisted analysis of tauri-apps/tauri@56d19c39e4 (2026-08-20). Data as JSON: /api/errors/a2b9d1ae25f1699a. Report an issue: GitHub.