Open Bug 1206391 Opened 9 years ago Updated 2 years ago

UX when navigating to a script from a revoked blob is confusing


(DevTools :: Debugger, defect, P3)

43 Branch


(firefox43 affected)

Tracking Status
firefox43 --- affected


(Reporter: jujjyl, Unassigned)


(Blocks 1 open bug)


(Whiteboard: [gaming-tools])


(1 file)

Three different errors here, possibly caused by same underlying bugs(?), so reporting as one:


1. Open view_source_blob.html in attachment.
2. Open page console, the page has by design an error "SyntaxError: expected expression, got '.'" (page developer is attempting to debug that error)
3. Click on the far right on the link "30911c94-8230-5545-8cdc-e6ce4a2ef7b4:10770:28" to jump in the debugger to the line where the error occurs.


A. In current Firefox Stable 40, there is a systematically reproducible crash:

however that crash no longer occurred in current Nightly, so this is possibly something that has already been fixed since.

B. In current FF Nightly 43.0a1 (2015-09-19), when clicking on the source, a new empty tab is opened which has the url "view-source:blob:null/30911c94-8230-5545-8cdc-e6ce4a2ef7b4". However, the page title is empty, and the page contents is empty. Expected: Instead of opening a new browser tab, the browser debugger should have opened up and showed the JS code source of the blob and the line where the SyntaxError occurred.

C. Continuing the STR: in the same empty tab that popped up with the URL "view-source:blob:null/30911c94-8230-5545-8cdc-e6ce4a2ef7b4", replace the URL and navigate to "".

Observed: Google main page is loaded, and a new alert dialog "Line not found: The specified line was not found <OK>" pops up on top of the Google search page. Clicking ok on the alert, a second alert popup comes up that says "Go to line: Enter line number <textbox> <Cancel> <OK>". Expected: These two popups should not appear. It looks like the tab has gone to some kind of bad state here from the previous failed navigation.
After reporting this I realized that the test case is using .revokeObjectURL() on the blob, so it is understandable that the debugger won't be available on it. However the odd behavior is still odd, perhaps the debugger window should open up, but instead of showing the source, it should show the blob URL and "(source not available)" in the source code listing?
We only fall back to view-source if we can't find the source ourselves. Perhaps we should embed view-source within the debugger's view in these cases?
Blocks: dbg-gaming
Whiteboard: [gaming-tools]
Priority: -- → P3
Product: Firefox → DevTools
Summary: Viewing source of .js code loaded from a blob gives various errors. → UX when navigating to a script from a revoked blob is confusing
Severity: normal → S3
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