1439040 - Various startup cache warnings

Status: NEW

(Core :: XPCOM, defect)

Description

[Eric Rahm [:erahm]]

We seem to be spamming a fair amount of startup cache warnings on startup. It's possible this is a build/packaging issue.

STR w/ a debug build:

#1) |./mach run|
#2) Wait a minute, close
#3) ./mach run
#4) Wait a minute, note warnings

I added code to dump the entries the warnings are upset about:

> Chrome file doesn't exist: /var/dev/erahm/mozilla-unified/layout/tools/layout-debug/ui/content/layoutdebug-overlay.xul
> [18631, Main Thread] ###!!! ASSERTION: Existing entry in disk StartupCache: xulcache/resource/gre/chrome/layoutdebug/content/layoutdebug/layoutdebug-overlay.xul: 'zipItem == nullptr', file startupcache/StartupCache.cpp, line 327
> 
> Chrome file doesn't exist: /var/dev/erahm/mozilla-unified/browser/base/content/report-phishing-overlay.xul
> [18631, Main Thread] ###!!! ASSERTION: Existing entry in disk StartupCache: xulcache/resource/app/chrome/browser/content/browser/report-phishing-overlay.xul: 'zipItem == nullptr', file startupcache/StartupCache.cpp, line 327
> 
> [18631, Main Thread] ###!!! ASSERTION: Existing entry in disk StartupCache: xulcache/resource/app/chrome/browser/content/browser/browser.xul: 'zipItem == nullptr', file startupcache/StartupCache.cpp, line 327
> 
> [Parent 18631, StartupCache] ###!!! ASSERTION: Existing entry in disk StartupCache: xulcache/resource/gre/chrome/layoutdebug/content/layoutdebug/layoutdebug-overlay.xul: 'NS_SUCCEEDED(rv) && hasEntry == false', file startupcache/StartupCache.cpp, line 385
> [Parent 18631, StartupCache] WARNING: cache entry deleted but not written to disk: xulcache/resource/gre/chrome/layoutdebug/content/layoutdebug/layoutdebug-overlay.xul: file startupcache/StartupCache.cpp, line 390
> 
> [Parent 18631, StartupCache] ###!!! ASSERTION: Existing entry in disk StartupCache: xulcache/resource/app/chrome/browser/content/browser/report-phishing-overlay.xul: 'NS_SUCCEEDED(rv) && hasEntry == false', file startupcache/StartupCache.cpp, line 385
> [Parent 18631, StartupCache] WARNING: cache entry deleted but not written to disk: xulcache/resource/app/chrome/browser/content/browser/report-phishing-overlay.xul: file startupcache/StartupCache.cpp, line 390
> 
> [Parent 18631, StartupCache] ###!!! ASSERTION: Existing entry in disk StartupCache: xulcache/resource/app/chrome/browser/content/browser/browser.xul: 'NS_SUCCEEDED(rv) && hasEntry == false', file startupcache/StartupCache.cpp, line 385
> [Parent 18631, StartupCache] WARNING: cache entry deleted but not written to disk: xulcache/resource/app/chrome/browser/content/browser/browser.xul: file startupcache/StartupCache.cpp, line 390

So it seems concerned about the following:
  - layoutdebug-overlay.xul
  - report-phishing-overlay.xul
  - browser.xul

The pattern is adding the entry to the cache, but it's already in the zip file and we warn [1], then trying to write out the cache and again it's already in the zip file and we warn [2], and then the zipwriter fails to write the entry and we warn [3]. The third failure makes sense because the zipwriter bails if there's already an entry [4].

I'm not sure if this warning is useful or not, but we could probably just either:
  a) Stop storing the entry in `PutBuffer` if it's already in the zip
  b) Remove the warnings that check if it's in the zip and still warn when writing fails and tailor the message for NS_ERROR_FILE_ALREADY_EXISTS

[1] https://searchfox.org/mozilla-central/rev/cac28623a15ace458a8f4526e107a71db1519daf/startupcache/StartupCache.cpp#329
[2] https://searchfox.org/mozilla-central/rev/cac28623a15ace458a8f4526e107a71db1519daf/startupcache/StartupCache.cpp#385-386
[3] https://searchfox.org/mozilla-central/rev/cac28623a15ace458a8f4526e107a71db1519daf/startupcache/StartupCache.cpp#391
[4] https://searchfox.org/mozilla-central/rev/cac28623a15ace458a8f4526e107a71db1519daf/modules/libjar/zipwriter/nsZipWriter.cpp#469-470

Comment 2

[Eric Rahm [:erahm]]

dholbert also saw something similar in bug 744652, but decided it was a build issue.

Comment 3

[Eric Rahm [:erahm]]

I see a few of these as well, they definitely seem to be related.

> [26741, Main Thread] ###!!! ASSERTION: Unexpected prototype node type: 'Not Reached', file /var/dev/erahm/mozilla-unified/dom/xul/nsXULPrototypeDocument.cpp, line 222

Note the node type is not 'Not Reached', it's some sort of enum.

I've been testing with a build produced from |mach build binaries| and also confirmed a |mach build| also shows the same errors.