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Troubleshooting

This page covers the most common problems encountered when using MerMEId MeLODy and explains how to resolve them.

For detailed error information, open your browser's developer console (press F12 or Ctrl+Shift+I, then go to the Console tab). Error messages from isomorphic-git and from the editor's own modules appear there and are usually descriptive enough to pinpoint the cause.

Clone Fails / No Branches Listed

Symptom: Clicking "Next" in the Add Repository dialog shows no branches, or displays an error.

Possible causes and solutions:

  • Wrong URL format. The repository URL must start with https:// (not http:// and not git@) and end with .git. Example: https://github.com/yourname/my-catalogue.git. Copy the URL from the "Clone" dropdown on GitHub/GitLab and make sure to select the HTTPS variant, not SSH.

  • Wrong token scope. Your personal access token must have permission to read the repository. On GitHub, this means the repo scope. On GitLab, this means read_repository. Tokens with only package or CI scopes will not work. Generate a new token with the correct scope if needed.

  • Repository is empty. A newly created repository that contains no commits cannot be cloned. GitHub and GitLab show an empty state page when you visit a repository with no commits. To resolve this, initialize the repository — the easiest way is to create it from the MerMEId MeLODy Template, which already contains an initial commit.

  • CORS proxy unreachable. If the proxy at https://cors.isomorphic-git.org is temporarily unavailable, all Git operations will fail. Try again after a few minutes.

Push Fails After Sync

Symptom: Clicking "Share files" fails with an error like "rejected — non-fast-forward" or similar.

Cause: The remote repository has new commits that your local copy does not have. This can happen if someone else pushed to the repository while you were working.

Solution:

  1. Click "Synchronise" (arrow-clockwise icon) to pull the latest changes.
  2. Once the pull completes successfully, try "Share files" again.

If the sync itself fails due to a conflict (see below), resolve the conflict before pushing.

Push Fails With Conflict Warning

Symptom: A conflict warning appears listing files that have been modified both locally and on the remote.

Cause: The same file was modified both in your local staged changes and in a remote commit. MerMEId MeLODy detects this before allowing the push and blocks the operation to prevent data loss.

Solution:

  • You need to unstage your local changes for the conflicting file(s) (use the Unstage button in the Share Files section), then synchronise.

Form Is Empty After Opening a File

Symptom: Clicking a .ttl file in the repository tree opens the editor panel but the form shows no fields or no data.

Possible causes:

  • The file contains malformed Turtle. If a .ttl file was edited outside the editor and contains syntax errors, shacl-form may fail to parse it and render an empty form. Check the browser console for parsing errors. Correct the file in a text editor or ask an admin.
  • The SHACL shape could not be loaded. If the shacl_file_location for the entity type is a URL that cannot be fetched (e.g. a wrong path or a 404), the form will be empty. Check the path in configuration/editor-default.ttl.

Search Returns No Results

Symptom: Typing in the search panel returns no results, even for entities you know exist.

Possible causes and solutions:

  • config.json is missing or has a wrong datasetBaseUrl. The search component fetches index files from the URL in configuration/config.json. If this file is missing or the URL is wrong (e.g. pointing to a non-existent page), no indexes will load. Open the repository's configuration/config.json and check the datasetBaseUrl value. It should point to a GitLab/GitHub Pages URL where the aggregated index .ttl files are published. For details on how datasets are built and published, see Datasets Generation.

  • Indexes have not been published yet. The index files are generated by a CI/CD pipeline that runs after each push. If the repository was just created or the pipeline has not run yet, there are no index files to fetch. Push at least one entity and wait for the pipeline to complete (usually under two minutes). Then click "Synchronise" or reload the page to trigger a fresh index reload.

  • Need to reload. After a push and pipeline run, the editor may need a manual trigger to reload the indexes. Click "Synchronise" or reload the browser page.

  • No repository is selected. If no repository is active (nothing is highlighted in the repository tree), the search panel does not know which dataset URL to use. Click your repository name to select it and click on the "Synchronize" button.

Editor Loads But No Repositories Are Shown

Symptom: The left panel is empty on first visit.

This is expected behaviour. MerMEId MeLODy stores everything in the browser's IndexedDB. On a fresh browser profile (or after clearing browser data), there are no repositories yet. Use the "Add repository" button (folder-plus icon) to connect your first repository by cloning it.

Changes Not Visible in Search After Pushing

Symptom: You pushed new or updated entities, but they do not appear in the search results.

Cause: The search index is generated by a CI/CD pipeline on your Git host (GitHub Actions or GitLab CI) after each push. This pipeline takes some time — typically 30 seconds to a few minutes.

Solution: Wait for the pipeline to finish. You can monitor its progress on GitHub (Actions tab) or GitLab (CI/CD → Pipelines). Once the pipeline has completed and the index files are published, click "Synchronise" in the editor to trigger a fresh reload of the indexes.

Browser Compatibility Issues

Symptom: A feature does not work as expected in a particular browser.

Recommendation: Use Chrome or Edge (any recent Chromium-based version) for the best experience. Both support all features used by MerMEId MeLODy, including IndexedDB, the File System Access API, and the Web Crypto API.

Firefox works for most operations (cloning, editing, saving, pushing, pulling, searching) but has limited support for the File System Access API. The local filesystem mode (direct access to a folder on your disk) may not be available in Firefox.

Safari is not officially tested. Some features may not work.

General Tip: Use the Browser Console

Most errors in MerMEId MeLODy produce a message in the browser's developer console. To open it:

  • Chrome / Edge: press F12 or Ctrl+Shift+I, then click the Console tab.
  • Firefox: press F12 or Ctrl+Shift+I, then click the Console tab.

Look for red error messages. isomorphic-git errors in particular are descriptive (e.g. HttpError: HTTP Error: 401 Unauthorized if your token is wrong, or MergeNotSupportedFail if a merge conflict occurred). Copy the error message when reporting a bug on GitHub Issues.