"I expect around 30 percent of users will suffer serious breakage that could have been avoided," wrote Debian developer Bill Allombert in an e-mail warning to the community. He said he was personally not satisfied with the state of the upgrade process to version 3.1, which was released earlier this week.
Allombert said many of the software bugs that would cause problems for users had previously been reported to Debian's bug-tracking database. He said he reached a number of conclusions by trying to artificially reproduce the reported issues.
Firstly, he said, a lot of problems were caused by software packages dependent upon other software packages, which in turn were dependent on the first lot in a cycle known as "circular dependencies". This would create problems installing or upgrading either bunch.
Also, key software installation tools 'apt' and 'aptitude' depended heavily on the C++ software library, which made them difficult to upgrade if the library changed. Compounding the problem, the tools needed to upgraded before most other software packages.
Thirdly the developer said far too many software packages tinkered with configuration files needed during the upgrade.
Allombert finally highlighted what he saw as a deficiency in the thoroughness of Debian's testing of the upgrade process.
The upgrade process should be tested continually during development, he said, because there was not enough time during a crucial code 'freeze' period immediately before the distribution's release date.
"Another conclusion is that this needs to be done automatically," he said. "Unfortunately I do not have access to suitable hardware anymore to do such [an] upgrade test, so help with this project would be more than welcome."
Allombert concluded by calling for Debian developers to achieve a better result for the project's next software release.
The news comes as Debian was forced to update version 3.1 of its distribution less than 24 hours after it was released this week. The software -- which has been three years in development -- was released with the security update feature disabled for installations from optical media.