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WebView state unexpectedly persists across sessions without a WebviewPanelSerializer #236494
Description
In the docs at https://code.visualstudio.com/api/references/vscode-api#WebviewPanelSerializer<T>, it says:
There are two types of webview persistence:
- Persistence within a session.
- Persistence across sessions (across restarts of the editor).
A
WebviewPanelSerializeris only required for the second case: persisting a webview across sessions.
The suggestion is that without a WebviewPanelSerializer, state is not persisted across sessions.
However, that's not what I'm seeing. I don't have a WebviewPanelSerializer but my state is persisting across restarts. I added the following to the top of my webview script:
const vscode = acquireVsCodeApi();
const originalState = vscode.getState();
const originalFrameUrl = originalState?.frameUrl;
console.log(\`State log: \${originalState.log?.join("\\n")}\`);
vscode.setState({
...(originalState ?? {}),
log: [...(originalState.log ?? []), \`Webview state added at \${new Date()}\`]
});Then I loaded the webview, ran "Reload Webviews" a few times, then shut down VS Code. Then when I re-opened VS Code and opened my webview, I saw the following:
This is not what I'd expect - I would've expected any state from previous launches of VS Code to be gone.
As an aside, things that aren't clear to me from the limited docs:
- is the intention that state is lost in VS Code restart, or extension host restart? What about "Reload Window"?
- is state shared across all webviews, or scoped by an id?
- does
setStatealways replace the entire object, or is there a way to add just new fields (I ask because if the state is shared amongst all webviews, that could result in them overwriting each others state)
Does this issue occur when all extensions are disabled?: Yes
Version: 1.96.0 (user setup)
Commit: 138f619
Date: 2024-12-11T02:29:09.626Z
Electron: 32.2.6
ElectronBuildId: 10629634
Chromium: 128.0.6613.186
Node.js: 20.18.1
V8: 12.8.374.38-electron.0
OS: Windows_NT x64 10.0.26100
Activity
mjbvz commentedon Dec 19, 2024
Can you share some example extension code for this. I tested with our built in markdown preview and don't see this happening
vs-code-engineering commentedon Dec 27, 2024
This issue has been closed automatically because it needs more information and has not had recent activity. See also our issue reporting guidelines.
Happy Coding!
DanTup commentedon Jan 6, 2025
Matt Bierner (@mjbvz) sorry for the delay. I can reproduce this with the
webview-view-samplesample. I replaced the reference to the external script with inline script:Then I run the extension and run Reload Window a few times. Then close the extension dev host, close VS Code. Reopen VS Code, and re-run and you see the issue:
DanTup commentedon Jan 22, 2025
Matt Bierner (@mjbvz) ping in case you didn't see this :-)
DanTup commentedon Jan 28, 2025
Matt Bierner (@mjbvz) ping :-)