Rewrite editor-preview package as extensions of editor classes

[colin-grant-work]

What it does

This PR is a more-or-less wholesale rewrite of the editor-preview package to extend and override the functionality of the EditorManager, EditorWidgetFactory, and EditorWidget rather than using a wrapper around an EditorWidget.

• Fixes [ui] Rename a file when the file is opened in Preview mode. #3634 by making the preview an immediate child of the shell
• Fixes navigation from the editor preview widget does not work #4061 by using a normal editor widget
• Fixes TypeError: Cannot read property 'addWidget' of null: cannot open editor widgets #4708 by reducing the complexity of the docking and widget-tracking logic
• Fixes [navigator] race condition between click and dblClick handlers  #6784, fixes Regression when opening an .MD file in editor: I can see two tabs for one editor #8511, fixes Race condition in Editor Preview Manager and Editor Manager #9485 by implementing better checks for a widget's prior existence and by using a single opening routine for all editors, rather than having two competing openers for previews and regular editor widgets.

These issues aren't directly addressed by these changes, but I can't reproduce them with this code:

• Closes alt+w doesn't close preview window #4903
• Closes preview: 'open preview' does not work for editor-previews #7078

Regressions:

• double-clicking the title of a preview editor will not pin that editor.

I think the best way to handle this problem is what I've outlined in #9511, but in the meantime, I've achieved this by using a listener on the document.

Breaking Changes:

• Change of various return types in WidgetOpenHandler and derived classes from Promise<T | undefined> to MaybePromise<T> | undefined to facilitate synchronous checks for widget existence.

I've removed this breakage by adding methods to the WidgetManager and WidgetOpenHandler that can check for a widget's (pending) existence synchronously rather than modifying existing methods.

How to test

Basics

1. Makes sure that the preference editor.enablePreview is true and run the Restore workbench layout command.
2. Single-click various files in the navigator.
3. One editor should be created, and it should be replaced with each new file opened.
4. Double click the file you have open in the tree.
5. That editor should switch to non-preview mode.
6. Single click another file.
7. A new editor preview should open up.
8. Single click the file in the pinned (non-preview) editor.
9. The non-preview editor should be revealed, and no new editor should be opened.
10. Focus the current preview editor and start typing.
11. It should turn into a normal editor.

Fixes

• Renaming
  1. Open a preview, then rename the file.
  2. The preview with the old name should be replaced with a new one with the new name.
  3. Single-clicking a different file should replace the preview.
• Navigating
  1. Open an editor preview in a source code file.
  2. Use context menu 'Go to references' or Shift + F12 to view a references peek widget
  3. Clicking on the destinations should work fine.
• Dragging
  1. Open a preview.
  2. Drag it into a side panel
  3. You should still see the editor.
  4. Drag it back
  5. It should be a non-preview
• Rapid opening
  1. Follow the reproduction instructions in Race condition in Editor Preview Manager and Editor Manager #9485
  2. You should never wind up with two editors.

Others

• Using ctrl+w (Electron) / alt+w (Browser) to close an editor preview should work.
• Opening a preview editor for e.g. a Markdown file and then using the Open preview should work as expected.

Review checklist

• as an author, I have thoroughly tested my changes and carefully followed the review guidelines

Reminder for reviewers

• as a reviewer, I agree to behave in accordance with the review guidelines

Signed-off-by: Colin Grant [email protected]

[kenneth-marut-work]

This is working much better and it seems to have fixed the issues mentioned above. On a first pass running through the functionality, I only noticed two small behavioral issues related to pinning:

1. Splitting the editor view in the main area

• Open 2 files (one being a preview)
• Drag the preview to the right side of the MAIN area to split the screen
• The preview does not pin

2. Pinning an editor when it does not exist in the file tree

• Open a file using the steps in Race condition in Editor Preview Manager and Editor Manager #9485 with a file that does not exist in your current workspace
• Observe that the file is opened as a preview widget, but it is not possible to pin it easily (now that the double clicking does not pin)
• In VSCode there is a context command for "Keep Editor Open" which might be a useful approach

[colin-grant-work]

@kenneth-marut-work, thanks for taking a look. I've made some changes to address your comments

• changed the drag logic to track the widget's tabbar rather than its parent to cover dragging inside the main area.
• added context menu commands and a keyboard shortcut parallel to VSCode's 'Keep Open' command.
• brought back the pin-on-double-click logic with a listener on the document.

[kenneth-marut-work]

Verified that the new context menu pin option and double clicking work 👍

[vince-fugnitto]

I verified the following functionality 👍

Preference editor.enablePreview:

• the preference is enabled by default
• when true editors are opened as a preview and replaced
• when false editors are opened normally and not replaced
• when toggling from true to false, the open preview editor is transformed into a normal editor

Application

• a preview editor is transformed into a normal editor when it is modified by a user
• a single-click in the explorer opens a preview editor when the preference is on
• a single-click in the explorer opens a normal editor when the preference is off
• a double-click in the explorer opens a normal editor (preference on)
• renaming a preview editor works correctly - the editor remains a preview
• dragging preview editors works correctly (sidepanel to main-area and so-on)
• keybinding successfully closes a preview editor
• splitting a preview editor works
• reloading the application with preview editors works
• performing toolbar actions (ex: 'markdown: open preview') should work for preview editors

[colin-grant-work]

@caseyflynn-google, this may be of interest to you. I plan to merge on Monday or Tuesday, if there are no objections.

[kenneth-marut-work]

Found one small issue, right clicking a file and using the "Open With" menu option reveals 2 "Code Editor" openers

[colin-grant-work]

Found one small issue, right clicking a file and using the "Open With" menu option reveals 2 "Code Editor" openers

@kenneth-marut-work, good find. Since WidgetOpenHandler was already bound to the EditorManager, I didn't need to bind it to the EditorPreviewManager again. I've removed that, and now there should be 1 (or 0) 'Open With' entries.

[caseyflynn-google]

Awesome work! Verified all items listed in the testing section:

How to test

Basics

1. Makes sure that the preference editor.enablePreview is true and run the Restore workbench layout command.
2. Single-click various files in the navigator.
3. One editor should be created, and it should be replaced with each new file opened.
4. Double click the file you have open in the tree.
5. That editor should switch to non-preview mode.
6. Single click another file.
7. A new editor preview should open up.
8. Single click the file in the pinned (non-preview) editor.
9. The non-preview editor should be revealed, and no new editor should be opened.
10. Focus the current preview editor and start typing.
11. It should turn into a normal editor.

Fixes

• Renaming

  1. Open a preview, then rename the file.
  2. The preview with the old name should be replaced with a new one with the new name.
  3. Single-clicking a different file should replace the preview.

• Navigating

  1. Open an editor preview in a source code file.
  2. Use context menu 'Go to references' or Shift + F12 to view a references peek widget
  3. Clicking on the destinations should work fine.

• Dragging

  1. Open a preview.
  2. Drag it into a side panel
  3. You should still see the editor.
  4. Drag it back
  5. It should be a non-preview

• Rapid opening

  1. Follow the reproduction instructions in Race condition in Editor Preview Manager and Editor Manager #9485
  2. You should never wind up with two editors.

Others

• Using ctrl+w (Electron) / alt+w (Browser) to close an editor preview should work.
• Opening a preview editor for e.g. a Markdown file and then using the Open preview should work as expected.

Additional checks:

• All context menu items in editor preview tab work (Close, Close Others, Toggle Maximized etc)
• Language server features work in editor preview
• Editor reviews are properly revived (only tested in browser)