Feature Request: Allow Custom Editors To Gracefully Handle Diff Views

[hediet]

It would be awesome if custom editors could influence the diff view (or opt out of it).

These are examples where the default diff view does not really work:

• 
• 

Unfortunately, the individual custom editor only knows if it is readonly, but not if it is right or left of a diff view.

Related:

• Viewing a graphical git diff for .yarn files should default to the built-in Text Editor, not the Yarn Loom editor TranquilMarmot/YarnLoom#19
• Handling/Disabling Diff Views in Custom Text Editors #97683

[Tyriar]

👍 hex editor and luna paint could also provide nicer diff experiences.

[fchen7i]

#171381 is slightly different. we want to use a new webview to do the compare

[starball5]

It would be nice if the user could have control over this using the View: Reopen Editor With... or View: Reopen Editor With Text Editor commands (which is the case for the "compare files" feature). Even nicer might be if such a control (dropdown?) were available in the action bar (at the top right of the workbench).

Related on Stack Overflow:

• How can I compare files in VS Code with an alternative editor?
• Different defaults for editing and comparing?

[zjffun]

Set default editor for diff view

We can use workbench.editorAssociations and configurationDefaults to set default editor for diff view, like:

Text editor diff view:

{
  "configurationDefaults": {
    "workbench.editorAssociations": {
      "{git,gitlens}:/**/*.{drawio,dio,dio.svg,drawio.svg}": "default",
    }
  }
}

Image preview diff view:

{
  "configurationDefaults": {
    "workbench.editorAssociations": {
      "{git,gitlens}:/**/*.{bmp,dib,ico,png,jif,jpe,jpg,jpeg,tga,tpic,webp}": "imagePreview.previewEditor",
    }
  }
}

Set different custom editor for diff view and edit view

{
  "configurationDefaults": {
    "workbench.editorAssociations": {
      "{git,gitlens}:/**/*.custom-ext": "custom-diff-editor",
    }
  },
  "customEditors": [
    {
      "viewType": "custom-editor",
      "displayName": "custom-editor",
      "selector": [
        {
          "filenamePattern": "*.custom-ext"
        }
      ],
      "priority": "default"
    },
    {
      "viewType": "custom-diff-editor",
      "displayName": "custom-diff-editor",
      "selector": [
        {
          "filenamePattern": "*.custom-ext"
        }
      ],
      "priority": "option"
    }
  ]
}

Example

Edit view:

Diff view:

---

PS: Currently it seems some bug with configurationDefaults in VS Code 1.85.0, and it's fixed #194087 . configurationDefaults with workbench.editorAssociations should work fine use in VS Code 1.86.0, and now we can already use workbench.editorAssociations to test various scenes.