Hi. I have allready sent this message but I believe it wasn't delivered, so i try again. I am currently working on a very large project and among other, I am in charge of the build process in which we use ant. I really like ant and its ideas and I've decided to get involved in the project. During the development of our project, the issue of incremental build had been brought up several times while using ant. In my opinion - it is one of ant's biggest flaws. I'll explain. We maintain all the build process as ant files in order to run nightly builds. The problem is that the build process is not applicable for a developer who had changed two-three files and want to run the project and test his/her changes. The full build process is highly time consuming - which is ok for night builds, yet unbearable for developers. The catch is that we don't want to re-write the building process in our IDE in order not to increase maintenance time and error probability of our building process. As for now, we maintain the classpaths and more of the build process (packing..) in two places - in the build file and in the IDE. My suggestion is to add ant a support for incremental build in the task level. Since the current state is that tasks do not support incremental build, this will remain the default. A -incremental option will be supported as an argument to ant, and then every task will be able to test the incremental flag of the project, and behave accordingly. For example - the copy task will behave under incremental build as follows - it will copy the files only if they do not exist or if they are "younger" at the target dir. Another example - the jar task will behave under incremental build as follows - it will touch the file only if one of the source files for the jar is "older" than the jar itself (pitfall - if the build process will use the same jar file name to create two different archives - by the second jaring the jar will be assumed as newer than its source files and therefore will not be packed). There are problems with adding support to all the tasks (for example delete) but it seems that it all can be solved elegantly (as for the delete problem, using sync task instead of delete and then copy will allow adding the incremental support to the sync task). The beauty is that after adding support for the -incremental option, it does not affect the tasks immediately, and instead you can go over it one by one, slow and easy, and add the incremental support. In other words - the change can be done with out adding the support to any task and can be a part of the new version even without task support - which makes this change much more subtle. The advantages are that ant will become a tool also for the developers, and the project will have a single point of build definition rather than two or more. Ant was said to have all the advantages of makefiles, but the lack of incremental support is definitely an advantage of makefiles which I miss the most. What do you say?
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