On Thu, Jan 27, 2011 at 1:11 PM, Ron Wheeler <rwhee...@artifact-software.com> wrote: > Does this matter?
Yes. A cycle is a serious dependency problem that gone unnoticed may be harder to fix later. > Is more than 1 copy of mygroup:compa:zip:vc-all:1.0.0 being included. Yes, in the sense that compa exists where it is checked out, and then another (older) copy of the binaries of compa gets unpacked below target\dependency. > It seems silly to make something dependent on itself and I can't imagine how Well obviously no one does it on purpose. > your would build it in the first place withyout getting an error. It can happen without getting an error. Just follow these steps and you'll see: 1. Make B that doesn't depend on anything. Deploy a snapshot of B. 2. Make A that depends on the snapshot of B . Deploy a snapshot of A. 3. Change B to depend on the snapshot of A. Now deploy a new snapshot of B (same version as in step 1). Now A depends on itself through B, but Maven gives no errors when building A. Now a tight cycle like this would not likely happen in real life because it's too obvious. But with a bigger dependency tree it can and actually DID happen to me just last week (well, not me personally; of course it was someone else at my workplace). > But for mygroup:compa:pom:1.0.0, it will get 1 > mygroup:compa:zip:vc-all:1.0.0 and that is what it needs. No, it was never intended for compa to depend on itself and of course it doesn't need to depend on itself. That's ridiculous and ought to result in an error. BTW, the type and classifier is kind of a red herring here. It shows "pom" because the packaging type is pom and "zip:vc-all" because the artifact is packaged as a zip with classifier vc-all, but that doesn't change the fact that it is compa depending on itself. Also, this can happen with "jar" packaging too, and then it would say "jar" in both places (I did that test too). > I am missing the harm that this does since it will get detected earlier in > the process. Wrong. See steps above. I guess I shouldn't be surprised that Maven doesn't detect a cycle as an error. It's just funny because before we even made the decision to go with Maven at my workplace, we had talked specifically about how a dependency management system would automatically prevent issues like cycles and version clashes. And we chose Maven, but Maven doesn't detect either of these. The good news is Maven is flexible with plugins. We wrote a plugin to detect version clashes, and it won't be hard to add cycle detection. We execute this in our parent pom during the validate phase, so it will fail when we want. I just can't believe no one else has run into this. Phillip --------------------------------------------------------------------- To unsubscribe, e-mail: users-unsubscr...@maven.apache.org For additional commands, e-mail: users-h...@maven.apache.org
