Hi Michael, On 6/18/2014 8:10, Michael Osipov wrote:
That argument does count "maintain backward compatibility" because Logback broke it already several times in a patch version:
1.1.2: Removed deprecated constructors in SocketAppender and related classes. 1.0.7: Groovy and Janino upgrade 1.0.2: By default PatternLayout will now output its pattern at the top of log files
and so forth, so it is a lousy argument.
Right. I am not advocating backward compatibility as an absolute principle which can never be infringed. There are occasions where backward compatibility needs to abandoned in light of other considerations. Let me respond to the examples you brought up where compatibility was broken:
1.1.2: Removed deprecated constructors in SocketAppender and related classes.
IMO, the code in SocketAppender needs to be partially re-written to make it less confusing. I'd expect much heavier changes there in the future.
1.0.7: Groovy and Janino upgrade
When a component that logback optionally depends on, e.g Janino, breaks compatibility, there is no alternative that can keep everyone happy in every case. No later than as yesterday, I was bitten by the Janino issue in a client project. My project relies on logback 1.1.3 for logging and on Janino 2.5 to perform certain computations. In order to enable logback features requiring Janino (version 2.6), I had to adapt parts of the project code to use Janino 2.6 (instead of 2.5). Luckily, the required changes were not too extensive *and* the affected code was under the control of my team. The problem would have become unsolvable otherwise. Had logback not upgraded to Janino 2.6 and stayed with 2.5, the compatibility problem would have been just as bad if my client project depended on Janino 2.6 (instead of 2.5).
1.0.2: By default PatternLayout will now output its pattern at the top of log files
The sentence "By default PatternLayout will now output..." is in the release notes [1] of version 1.0.2 dated 2012-04-26. However, the sentence that _just_ follows it, states: This feature, although still available, is no longer enabled by default. See release notes for version 1.0.3 for details. In 1.0.2, it was decided to add by default a comment at the top each log file in order to help with the parsing. After the release of 1.0.2, several people complained about the change. See http://jira.qos.ch/browse/LOGBACK-201 A survey was created to request user input. It appeared that a majority of the users preferred not to enable by default printing of the pattern as the first line in the log files. Bowing to popular demand, the compatibility breaking change was *reverted* in 1.0.3. It seems to me that the ISO8601-related case bears many resemblances to LOGBACK-201. Cheers, [1] http://logback.qos.ch/news.html
Michael
-- Ceki