"Invalid Tab" Messages in Log

[tsmaeder]

Bug Description:

While testing the 1.52.0 release, I found a bunch of error messages of the following for in the browser log:

bundle.js:2 Uncaught (in promise) Error: INVALID tab
    at u.acceptTabOperation (/C:/Users/thomas/AppData/Local/Programs/TheiaIDE/resources/app/lib/frontend/C:\Users\thomas\AppData\Local\Programs\TheiaIDE\resources\app\lib\backend\339.js:1:519975)
    at t.TabsExtImpl.$acceptTabOperation (/C:/Users/thomas/AppData/Local/Programs/TheiaIDE/resources/app/lib/frontend/C:\Users\thomas\AppData\Local\Programs\TheiaIDE\resources\app\lib\backend\339.js:1:522339)
    at /C:/Users/thomas/AppData/Local/Programs/TheiaIDE/resources/app/lib/frontend/C:\Users\thomas\AppData\Local\Programs\TheiaIDE\resources\app\lib\backend\366.js:1:35962
    at process.processTicksAndRejections (VM1720 task_queues:95:5)
    at async c.handleRequest (/C:/Users/thomas/AppData/Local/Programs/TheiaIDE/resources/app/lib/frontend/C:\Users\thomas\AppData\Local\Programs\TheiaIDE\resources\app\lib\backend\638.js:1:46979)

Errors in tab tracking are more relevant than they may appear because the typescript language server relies on tracking the active tab to decide which files to error check, for example.

Steps to Reproduce:

n/a

Additional Information

• Operating System: Windows 11
• Theia Version: 1.52.0 preview

[tsmaeder]

I was able to reproduce the issue in the electron sample app, but only after working for a couple of hours. The editor I closed was a new file, I believe.

[tsmaeder]

I added some debug logging and it seems the invalid tab messages always come from TabOperation.UPDATED operations, which get invoked upon the Title.changed signal.

{
   "kind":2,
   "index":-1,
   "tabDto":{
       "id":"11~code-editor-opener:file:///c%3A/Users/thomas/code/theia/packages/core/src/browser/shell/tab-bar-toolbar/tab-bar-toolbar-registry.ts:1",
       "label":"tab-bar-toolbar-registry.ts",
       "input":{
           "kind":1,
           "uri":{
               "$mid":1,"path":"/c:/Users/thomas/code/theia/packages/core/src/browser/shell/tab-bar-toolbar/tab-bar-toolbar-registry.ts",
               "scheme":"file"
           }
       },
       "isActive":false,
       "isPinned":false,
       "isDirty":false,
       "isPreview":false
   },
   "groupId":11
}

[tsmaeder]

I suspect the -1 index comes from tabs-main.ts#updateTabIndices#349. It's the only place I could find where -1 might be set as the index.

[tsmaeder]

I was able to catch the moment the -1 index happens in the debugger. It happened when I was closing a tab: The situation was as follows:

• Open Tabs: promise-util.ts | lib.es5.d.ts | tab-bar-toolbar-registry.ts | tab-bar-toolbar.tsx | tab-bar-toolbar-types.ts | widget.d.ts
• Tab being closed was "lib.es5.d.ts"
• In updateTabIndices, the tabInfo is the tab being closed (lib.es5.d.ts),
• the tab being updated is tab-bar-toolbar-registry.ts
• tab.group.tabs at this point contains twice the tab for tab-bar-toolbar.tsx instead of tab-bar-toolbar-registry.ts | tab-bar-toolbar.tsx

=> so the tabInfo.group.tabs values are already corrupt that this point. Not clear whether the structure has been rebuilt or if it was corrupted incrementally.

[tsmaeder]

Since I did not move any tabs, I think the duplicat tab must come from tabs-main.ts#onTabTitleChanged(), there, it says:

if (!this.tabDtosEqual(oldTabDto, newTabDto)) {
            tabInfo.group.tabs[tabInfo.tabIndex] = newTabDto;

What if tabInfo.tabIndex is not the same as the previous index in the group? Is that even possible?