CODEWITHSUNDEEP
maven
l4rmbr
l4rmbr

Reputation: 1307

How to resolve this weird dependency in maven?

Have 3 projects. B depends on A, C depends on A and B. Both A and B depend on a package P of version 1, namely P1. Now C introduce another versoin of P, name it P2.

The denpendency tree may looks like

  P1   P1
  ^     ^
  |     |
  A  <- B
  ^     ^
   \   /
    \ /
     C -> P2

To avoid P confilict, I decide to prune P1, by modifying the pom.xml in A and B. But weird
thing occurs: when I ran mvn eclipse:eclipse in C, I found it still try to resolve the dependency of P1 !

I then carefully checked every project.

In A:  Re-check the pom.xml -> NO dependency of P1 , it won't resolve P1 !

In B:  Re-check the pom.xml -> NO dependency of P1 , it won't resolve P1 !

In C:  Re-check the pom.xml -> NO dependency of P1 itself , but it DOES resolve P1!
  |
  | -  Comment out dependency of A:  Resolve P1 !
  |
  | -  Comment out dependency of B:  Resolve P1 !
  |  
  | -  Comment out dependency of both A & B: Won't resolve P1 !

Finally, I make sure that other packages of A , B and C that depend on do not
 depend on  P1(Actually, P1 is a small SDK with limited usage, I'm sure other
 packages won't denpend on it)

So Here is the weird thing: From the check, it seems either A or B introduces P1, but in A and B respectively, I check and conclude that neither will introduce P1.

Anything wrong?

UPDATE

I finally figure out what is wrong: see the answer.

Upvotes: 0

Views: 157

Answers (2)

l4rmbr
l4rmbr

Reputation: 1307

I finally figure out what is wrong:

From mvn dependency:tree in C, I found that P1 exists in the sublevel of B.jar. So I went to B and ran mvn clean install to update B.jar, then went back to C, and now everything is OK.

I think this might be what happens:

Since B is project-depending on P1, so the old file in B.jar that records the dependency of B(actually I extracted B.jar and found it is called META-INF/maven/path/to/B/pom.xml) DOES NOT update as the pom.xml in B does. So when I ran mvn eclipse: eclipse in C, it resovles B(C is also project-denpending on B, so it resolve B.jar ), which then resovles P1 by the dirty pom.xml in B.jar, not the fresh pom.xml in B). I think this is a poor design and ambiguous-bug-prone!

Upvotes: 1

Samuel EUSTACHI
Samuel EUSTACHI

Reputation: 3156

Try to run mvn dependency:tree on project C, you should see where P1 comes from.

Upvotes: 0

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