544800 - Download Manager overwrites downloaded files when Firefox is restarted after disk full error

Status: UNCONFIRMED

(Toolkit :: Downloads API, defect)

Description

[klaus_p_koch]

User-Agent:       Mozilla/5.0 (X11; U; Linux i686; de; rv:1.9.2) Gecko/20100115 Firefox/3.6
Build Identifier: Mozilla/5.0 (X11; U; Linux i686; de; rv:1.9.2) Gecko/20100115 Firefox/3.6

When files are downloaded to the home partition (or the partition that contains the .mozilla folder), and the disk gets full before the downloads are completed, unexpected and unnecessary data losses can occur:
The downloads window freezes, becomes unresponsive. After closing Firefox, freeing up some space on the partition and restarting Firefox, Firefox tries --without asking-- to restart all downloads that were still in the list, whether finished or not. All these previous downloads are overwritten instantly. If the download URL is still valid, this is just a loss of time and bandwidth. If it was a one-time URL (as with share hosters, paid content etc.), the download is lost permanently.

Reproducible: Always

Steps to Reproduce:
1. Download several files to your home partition until it runs out of memory
2. Close Firefox, free up some space on your home partition
3. Restart Firefox
Actual Results:  
Downloads are lost, including those that were finished, but still in the list

Expected Results:  
Firefox should never overwrite completed downloads without asking.
Even unfinished downloads should not be overwritten without asking.
The downloads window should not become unresponsive.


When the downloads window is "frozen", it is still possible to download files. These downloads will be "invisible" to the downloads windows.
I am using Ubuntu 9.04, no special themes or plugins.
A workaround for this bug is to delete the downloads.sqlite file in the .mozilla folder before restarting Firefox.
I suspect the bug has to do with Firefox being unable to update this file when the drive is full.
It seems to me that the worst troubles can be cured if this file is updated every time a download has been successfully completed.
But an able developer should be able to come up with a solution that follows a more systematic approach. The 'replace a text file' method of download management does not seem to me to be robust enough for a "mass product" like Firefox.
Personally, I think this is a major bug, but I hope it will still be fixed if I categorize it as "normal."

Comment 1

[klaus_p_koch]

Bug 471067 is related to this one. In the comments there, several people confirmed my observations. I do believe, however, that my description is closer to the heart of the problem. Marking this report as a duplicate of bug 471067 is therefore not a good idea. The two should be merged into a 'best of both worlds' version.