VSCode CustomEditor - SaveAs command cannot be executed

[VadimGroGit]

Bug Description:

Standard MS sample for Custom Editor API
https://github.com/microsoft/vscode-extension-samples/tree/main/custom-editor-sample

For both editors ( CustomTextEditor, CustomEditor ) , the SAVE_AS command doesn’t work when
running in Theia (neither when called from the menu, nor by Ctrl-Shift-S).
The SAVE command works absolutely correctly.

In VS code, both commands work fine.

Steps to Reproduce:

1. Build sample : https://github.com/microsoft/vscode-extension-samples/tree/main/custom-editor-sample
2. Theia -> install from .VSIX
3. open any plugin exampleFiles ( .catScratch or .pawDraw )
4. try to SaveAs ( it doesn't matter with or without editing )

Additional Information

As far as I could figure out, the reason is here :

the MS sample implements methods from the interface CustomEditorProvider

saveCustomDocument(..)
saveCustomDocumentAs(..)

But in Theia, in FilesystemSaveableService does not use the method saveCustomDocumentAs(..).
Instead, when executing the SAVE_AS command, calls to the

widget.saveable.createSnapshot or
widget.saveable.serialize

methods are used.

See the implementation of the methods

FilesystemSaveableService : canSaveAs(..)
FilesystemSaveableService : saveSnapshot(..)

Thus, the method saveCustomDocumentAs(..), which is implemented in
class PawDrawEditorProvider implements vscode.CustomEditorProvider<..>,
is never called.

• Operating System: Windows 10, Fedora 41
• Theia Version: 1.58.100, 1.57.100

[msujew]

I've filed #14972 to fix this.

[VadimGroGit]

Thanks, Mark.
It looks promising.