Exposing developer tools contexts in runtime.getContexts() API

[sohailrajdev97]

Exposing developer tools contexts in runtime.getContexts() API

WECG proposal for runtime.getContexts()

https://github.com/w3c/webextensions/blob/main/proposals/runtime_get_contexts.md

Background

Extensions can customize the browser developer tools. When an extension customises the developer tools, it can run code in the following contexts:

1. Developer tools page: This is a background page which is spawned as soon as developer tools is opened. Its lifetime is tied to the developer tools.
2. Developer tools panel: This is a panel which the extension can add to the developer tools by calling devtools.panels.create() from the developer tools page (1).
3. Developer tools sidebar pane: This is a side pane which the extension can add to a particular panel (2) by calling devtools.panels.<panel>.createSidebarPane() from the developer tools page (1).

Proposal

All the above contexts host extension content (HTML and JavaScript). These should be available in the results of runtime.getContexts() API. runtime.getContexts() asynchronously returns a list of ExtensionContext objects. Following is a description of how ExtensionContext’s fields would be populated for developer tools contexts.

• contextType: Three new context types would be added (one for each context described above)
  1. DEVTOOLS_PAGE for developer tools page.
  2. DEVTOOLS_PANEL for developer tools panel.
  3. DEVTOOLS_SIDEBAR_PANE for developer tools sidebar pane.
• tabId: -1 as these contexts are not associated with a browser tab.
• windowId
  • If developer tools are docked, the ID of the parent window (to which it is docked).
  • If developer tools are undocked, the ID of the window hosting developer tools.

Other fields (contextId, documentId, frameId, documentUrl, documentOrigin, incognito) should be populated as expected. No special handling is needed for them.

Current support

1. Firefox 129 does not return these contexts via the API call.
2. Chrome 129 returns these contexts with a “TAB” context type, which is incorrect.

Compatibility issues

Chrome already returns developer tools contexts via the API; some extensions might be using that information. Currently the contexts are returned with the “TAB” context type and that is a bug.

Creating this issue to get group's feedback. We will create a follow-up PR to modify the runtime.getContexts() proposal after we have consensus within the group.

[oliverdunk]

Thanks again for filing this @sohailrajdev97. On the Chrome side, we are supportive - we would prefer only a single new ContextType variant to avoid adding several. We should also work together to communicate the change to developers before it happens since it is a behavior change, even if adoption is low.

Looking forward to seeing this progress :)

[Rob--W]

I filed this bug on the Firefox side to implement DEVELOPER_TOOLS in runtime.getContexts(): https://bugzilla.mozilla.org/show_bug.cgi?id=1918719