gitGraph throws error in wrong format for live editor.

Describe the bug

Cannot change the main branch to anything.

To Reproduce Go to https://mermaid.live and select Git Graph from the samples pane.

Change config to this:

{
  "theme": "default",
  "gitGraph": {
    "mainBranchName": "trunk"
  }
}

Go back to the diagram and try to change main to trunk. It blinks and won’t change anything. The console lights up with errors like this:

Uncaught Error: D.hash.loc is undefined

S@https://mermaid.live/_app/pages/edit.svelte-6f83f87b.js:109:13610
ln/</<@https://mermaid.live/_app/chunks/index-3ccfa173.js:4:906
ln/<@https://mermaid.live/_app/chunks/index-3ccfa173.js:4:892
In/</</<@https://mermaid.live/_app/pages/edit.svelte-6f83f87b.js:14:1891

Trying it the other way around - changing main to trunk in the editor first (before config), logs that a branch isn’t created yet, as expected, then changing main in config to trunk resets the editor back to main.

Expected behavior

The editor shall allow users to change the name of the main branch to an arbitrary name.

Desktop (please complete the following information):

• OS: Windows 10
• Browser: FireFox, Chrome
• Version: both latest, as of this post

[ashishjain0512]

This issue is now fixed. Verified in Mermaid Live Editor against mermaid v9.1.6

[sidharthv96]

@ashishjain0512, I’m fixing the editor hanging issue in mermaid-js/mermaid-live-editor#864. But the issue happened because the Error thrown by the gitGraph is totally different from the Error thrown by other diagram types. It lacks the e.hash.loc data, so we can’t highlight where the error is in the code.

My current fix handles the situation and shows the thrown error above the diagram, but we should standardize the errors thrown by all diagram types.

try {
    mermaid.parse(state.code);
  } catch (e) {
    processed.error = e;
    console.error(e);
    if (e.hash) {
      try {
        const marker: MarkerData = {
          severity: 8, // Error
          startLineNumber: e.hash.loc.first_line,
          startColumn: e.hash.loc.first_column,
          endLineNumber: e.hash.loc.last_line,
          endColumn: (e.hash.loc.last_column as number) + 1,
          message: e.str
        };
        processed.errorMarkers = [marker];
      } catch (err) {
        console.error('Error without line helper', err);
      }
    }
  }