FUSETOOLS2-689 - fixing webview disposed error

[bfitzpat]

Signed-off-by: bfitzpat@redhat.com bfitzpat@redhat.com

[apupier]

Can you explain why the dispose method and the wrapDidactContent are called although the Webview is disposed? Can it hide another issue?

[bfitzpat]

Can you explain why the dispose method and the wrapDidactContent are called although the Webview is disposed? Can it hide another issue?

I could move it up further, in _update, but I put the fix where the error was appearing. I have not seen any other issues in my testing.

[apupier]

_update

why _update is called although the webview is disposed? Shouldn't be dereferenced from somewhere when the dispose is called?

[bfitzpat]

Since there are NO other indicators of trouble, I am going with the simplest solution to solve the issue that was presented. We had messages that appeared in a test console indicating that the webview was disposed and those messages did not prevent tests from passing. I found a solution that was used elsewhere to handle a similar problem (microsoft/vscode@5a0ead5). End of story. I'm not going looking for trouble.

[apupier]

Just hiding the error log might hide a bigger problems. A problem with not-disposed elements might be a sign of a memory leak. It can also be less harmful like just a problem of wrong order of operations during disposal. i'm asking because i think that it is importan to know if we know what is the root cause. If it is a memory leak it can be important to at least create another issue to investigate as it won't be very visible anymore given that the log has been removed.

[lhein]

One oddity I spotted right now is

vscode-didact/src/didactWebView.ts

Line 225 in 239887b

this._panel.onDidDispose(() => this.dispose(), null, this._disposables);

If I understand well then this handler will call the dispose function whenever the 'vscode.WebviewPanel' is disposed. However in the dispose function we call there is another call to the 'vscode.WebviewPanel's dispose function.
See

vscode-didact/src/didactWebView.ts

Line 288 in 239887b

this._panel.dispose();

.

So we basically try to dispose the same object 2 times which most likely causes the initial error and all the other handlings added by this PR are probably not even needed to fix the issue. Please correct me if I am wrong.

spotted a problem

[bfitzpat]

Please correct me if I am wrong.

Though we can explicitly dispose the object ourselves, there are listeners in place already that also have to handle that responsibility. Think things like when the window closes. We do not explicitly listen for such events and rely on the onDispose handler to call it for us. We do call it explicitly when the user opens a new didact file -- disposing the old panel and creating a new one. We're not disposing it twice. The dispose function is called in two places, but it's not redundant.

[bfitzpat]

Spinning off the separate issue to handle it - https://issues.redhat.com/browse/FUSETOOLS2-698