126563 - Starting a second browser instance deletes existing cache

Status: RESOLVED DUPLICATE of bug 76431

(Core :: Networking: Cache, defect)

Description

[Krishnakumar B]

From Bugzilla Helper:
User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:0.9.8+) Gecko/20020219
BuildID:    2002021906

Starting a new instance of the browser (not a new window) results in the browser
deleting the cache directory. So the existing browser doesn't load any more
pages and pops out messages that the URL is valid. This is because the cache has
been deleted from undeneath it by the new browser instance. This seems broken.

Reproducible: Always
Steps to Reproduce:
1.Start the browser. Browse a few pages and fill up cache.
2.Open a new browser instance (not a new window)
3.Close the new browser. Now try reloading a page or visiting a new page from
the personal toolbar.

Actual Results:  Unable to browse in the old window. Reloads, history don't work.

Expected Results:  I should be able to browse in the old instance of the browser.


I straced the second instance of Mozilla and have attached the output. It is
obvious that it deletes the whole directory. It happens irrespective of whether
I crashed previously (I saw that if Mozilla is recovering from a crash it will
delete the cache directory). I confirmed this by removing ~/.fullcircle. 

If sharing of cache between two instances of Mozilla is not possible, it should
atleast give the behaviour of Netscape 4.x where it warned that history and
cache is unusable. Or warn that another instance is running and exit. It should
definitely not go ahead and delete the directory and render an existing instance
unusable. 

My cache directory is /tmp/Cache.

Comment 1

[Krishnakumar B]

Attachment: strace of second mozilla instance

Comment 2

[gordon]

Are the two instances using the same profile, or do you have separate profiles
pointing to the same cache directory?

Multiple instances using the same cache directory is not supported.

Comment 3

[Krishnakumar B]

> Are the two instances using the same profile, or do you have separate profiles
> pointing to the same cache directory?

The two instances share the same profile. However I didn't set any profile
explicitly. So it is using the default profile. In fact, I just didn't create
any profile at all. I just changed some of the default options and I think these
changes went into the default profile.

> Multiple instances using the same cache directory is not supported.

However I didn't specify it do so. I also don't see any option to specify a
different cache directory for each instance. I see that you will have to do a
lot of book keeping to support sharing of cache directory among different
instances. But what I fail to see is why it should delete the cache without
warning the user. If this is indeed the behaviour, it should be listed in the
release notes. My apologies if I have missed that. All I read was that multiple
users are supported only if I use the script that was given in the release notes. 

If what you suggest is true, if I inadvertently open another browser (say with
some hotkey on MS keyboard), I can't use my existing browser window anymore. I
think such a behaviour is very broken.

Comment 4

[gordon]

Yes, such behaviour is broken.  We have a bug open to fix this problem (bug
76431  ).  I just wanted to confirm that it was likely the same issue.

I'm going mark this as a duplicate of bug 76431.  Thanks for the well-written
report.

*** This bug has been marked as a duplicate of 76431 ***

Comment 5

[Intermittent Failures Robot]

1 failures in 5144 pushes (0.0 failures/push) were associated with this bug in the last 7 days.

Repository breakdown:

• autoland: 1

Platform breakdown:

• linux64: 1

For more details, see:
https://treeherder.mozilla.org/intermittent-failures.html#/bugdetails?bug=126563&startday=2019-12-02&endday=2019-12-08&tree=all