oraios/serena · error · RuntimeError

Failed to install pasls and no local version available

Error message

Failed to install pasls and no local version available

What it means

Raised by PascalServer's _setup_runtime_dependencies when the automatic download/install of pasls failed (API or network problem) AND no previously installed pasls executable exists locally. The server needs the pasls binary and cannot fall back to a cached version.

Source

Thrown at src/solidlsp/language_servers/pascal_server.py:760

                else:
                    need_download = True
                    checksums = cls._get_checksums()
            else:
                log.debug(f"pasls is up to date: {local_version}")

        if need_download:
            if cls._atomic_install(pasls_dir, deps, checksums):
                # Update metadata after successful installation
                if latest_version:
                    cls._save_local_version(pasls_dir, latest_version)
                else:
                    # API failed but download succeeded, record placeholder version
                    cls._save_local_version(pasls_dir, "unknown")
                cls._update_last_check(pasls_dir)
            else:
                # Installation failed, use existing version if available
                if not os.path.exists(pasls_executable_path):
                    raise RuntimeError("Failed to install pasls and no local version available")
                log.warning("Update failed, using existing version")

        # Update check time even if no update (avoid frequent checks)
        if not need_download and cls._should_check_update(pasls_dir):
            cls._update_last_check(pasls_dir)

        assert os.path.exists(pasls_executable_path), f"pasls executable not found at {pasls_executable_path}"

        # Ensure execute permission
        try:
            os.chmod(pasls_executable_path, 0o755)
        except OSError:
            pass  # May fail on Windows, ignore

        log.info(f"Using pasls at: {pasls_executable_path}")
        return quote_windows_path(pasls_executable_path)

    def _create_base_initialize_params(self) -> dict:

View on GitHub (pinned to 7fcbca7e62)

Solutions

Check network access/proxy settings and retry the download (ensure HTTPS to the pasls release endpoint works).
Manually install pasls and place the executable at the expected pasls resources directory (where pasls_executable_path points), then restart.
If a previous pasls exists elsewhere, copy it into the expected directory so the fallback check succeeds.
Disable/avoid the update path by pre-seeding a valid local version file so the library uses the existing version instead of downloading.

Example fix

// before (offline first run)
server = PascalServer(repo_root)  # download fails, no local pasls
// after
# pre-provision pasls binary at the expected location
shutil.copy("/opt/tools/pasls", expected_pasls_dir / "pasls")
os.chmod(expected_pasls_dir / "pasls", 0o755)
server = PascalServer(repo_root)

Defensive patterns

Strategy: retry

Validate before calling

import os
def pasls_available(expected_path):
    return os.path.exists(expected_path)

Try / catch

try:
    server = PascalServer(repo_root)
except RuntimeError as e:
    if "Failed to install pasls" in str(e):
        check_network_and_proxy()
        provision_pasls_manually(expected_dir)  # copy/verify a known-good pasls binary
        server = PascalServer(repo_root)
    else:
        raise

Prevention

Pre-install pasls into the resources dir so the fallback path succeeds
Allow outbound HTTPS to the pasls release endpoint in CI/proxies
Cache the pasls directory between CI runs
Retry the setup once on transient network failures

When it happens

Trigger: Instantiating PascalServer when the update-check attempts a download, the installation fails (network/API error), and pasls_executable_path does not exist on disk (never installed or deleted).

Common situations: First run on a machine with no cached pasls while the download endpoint is unreachable; offline/air-gapped environment; corporate proxy blocking the download URL; API returning an error before download completes.

Related errors

AI-assisted analysis of oraios/serena@7fcbca7e62 (2026-08-29). Data as JSON: /api/errors/2ba8a7e312946295. Report an issue: GitHub.