FTR Jira issues https://issues.apache.org/jira/browse/MNG-7906 https://issues.apache.org/jira/browse/MNG-7854 https://issues.apache.org/jira/browse/MPH-183 and all linked issues
I don't know how this is relates with bom packaging in Maven 4 https://maven.apache.org/guides/introduction/introduction-to-dependency-mechanism.html#Bill_of_Materials_.28BOM.29_POMs The fact that this dependencyManagement import happens at effective model building stage, and not during dependency resolution, created specific complexity on how to analyze conflict resolution, report (not possible to dependency-tree -Dverbose), and have solutions for end-user to override default conflict resolution result. I dislike the currently non-actionable WARNINGs, particularly when actionable solution when a conflict resolution does not bring you the result you want, you can override by declaring a dependencyManagement entry before import. On what conflict resolution algorithm is in place, should we change it, to which one: discussion never went to a solid proposition. Notice that we don't have great usable documentation on that feature and its problems: just long discussions in Jira issues. I discover here what I'll call a new proposal from Tamasz: 1. promote avoiding multiple conflicting dependencyManagement imports, as they are hard to analyze 2. promote a merging tool where these conflicts can be worked on and choices done: first wins? last wins? (personal addition) greater wins? I'm sure some reporting on BOM POMs could also be interesting, given they started small and easy to get when used individually, but went complex when people started to assemble them HTH Hervé Le mardi 18 mars 2025, 18:47:49 CET Tamás Cservenák a écrit : > Howdy, > > Problem with BOM imports is that they were never "done done" in Maven > 3.x time-frame, and they work the total opposite to everything else in > Maven (think dependencies, as Delany says), hence they work in "non > Maven way", not intuitive way, and tend to cause (usually bad) > surprises. Sadly, they are overused in many projects, especially with > recursive-imports happening. Maven 4 just tries to warn you about > these, when a dependency is "stepping on toe" of another dependency, > but again, as a consumer, you have not much control over it. > Personally, I'd avoid using BOMs like these, and I'd preferably > generate my own. > > In short, BOMs should be > * flat (no recursive import) > * generated > * curated > > Sadly, with BOM you point at, none of these stands. Maven 4 tries to > "fix" things, that's all. Same as with CI Friendly support, this is > just yet another "incomplete" implementation. > > Personally, I'd prevent or better REMOVE recursive import capability > (so dep type=pom scope=import would NOT recursively import anything) > -- just to force them to be flat for start. > BOMs should be curated and generated (and flat). > > For these cases: > * take a peek at BOM generator (used in Maven build as well): > https://github.com/maveniverse/bom-builder-maven-plugin > * took a stab for a tool I'd use: BOM flatten, try it > out!https://github.com/maveniverse/toolbox/pull/180 > > Regarding flatten-BOM: again, perso I'd NOT use BOM specified by you, > but instead I'd deploy "flattened" BOM under my namespace (see gist > example) and use that. Given it is generated, you can just generate > new for any new version out there, > > > My 5 cents > T > > On Mon, Mar 17, 2025 at 8:43 PM Karl Heinz Marbaise > > <khmarba...@gmx.de.invalid> wrote: > > Hi to all, > > > > currently I'm trying to build a simple spring boot application which > > uses a BOM for spring-boot-dependencies.. > > > > <dependency> > > > > <groupId>org.springframework.boot</groupId> > > <artifactId>spring-boot-dependencies</artifactId> > > <version>3.3.3</version> > > <scope>import</scope> > > <type>pom</type> > > > > </dependency> > > > > So based on the releases of JUnit Jupiter, Mockito etc. > > I define the BOM's of JUnit Jupiter and Mockito (and others; only > > excerpts shown here) before the spring boot dependencies like this, > > because I want to use newer versions, than spring-boot-dependencies > > defines.> > > <dependencyManagement> > > > > <dependencies> > > > > <dependency> > > > > <groupId>org.junit</groupId> > > <artifactId>junit-bom</artifactId> > > <version>5.12.1</version> > > <type>pom</type> > > <scope>import</scope> > > > > </dependency> > > <dependency> > > > > <groupId>org.mockito</groupId> > > <artifactId>mockito-bom</artifactId> > > <version>5.16.1</version> > > <scope>import</scope> > > <type>pom</type> > > > > </dependency> > > .. > > <dependency> > > > > <groupId>org.springframework.boot</groupId> > > <artifactId>spring-boot-dependencies</artifactId> > > <version>${spring.boot.version}</version> > > <scope>import</scope> > > <type>pom</type> > > > > </dependency> > > .. > > > > </dependencies> > > > > </dependencyManagement> > > > > If I build the project Maven 4.0.0-rc3 I got a bunch of warnings like > > this: > > mvn clean -e > > [INFO] Error stacktraces are turned on. > > [INFO] > > ..... > > [INFO] Scanning for projects... > > [WARNING] > > [WARNING] 26 problems were encountered while building the effective > > model for 'com.soebes.spring.example:employee:jar:0.0.1-SNAPSHOT' (use > > -e to see details) > > [WARNING] Ignored POM import for: > > org.assertj:assertj-core:jar:3.25.3@compile as already imported > > org.assertj:assertj-core:jar:3.27.3@compile. Add the conflicting managed > > dependency directly to the dependencyManagement section of the POM. > > [WARNING] Ignored POM import for: > > org.assertj:assertj-guava:jar:3.25.3@compile as already imported > > org.assertj:assertj-guava:jar:3.27.3@compile. Add the conflicting > > managed dependency directly to the dependencyManagement section of the > > POM. > > [WARNING] Ignored POM import for: > > org.junit.jupiter:junit-jupiter:jar:5.10.3@compile as already imported > > org.junit.jupiter:junit-jupiter:jar:5.12.1@compile. Add the conflicting > > managed dependency directly to the dependencyManagement section of the > > POM.... > > > > In Maven 3.9.9 I can build that project without any warning, because the > > junit-bom is defined before the spring-boot-dependencies (which has > > junit-bom on it's own in an older version), but overwrites the defined > > in the spring-boot-dependencies with the newer versions, which is > > exactly what I want.. > > > > Back to Maven 4: > > So does that mean I have to add all the deps which are coming from the > > junit-bom (also for the deps from assertj-bom, mockito-bom etc.) > > manually into my dependencyManagement, as suggested? > > > > That will wipe away any advantage that using BOMs gives me. > > > > Is there a better solution which I'm not yet aware of? > > > > Kind regards > > Karl Heinz Marbaise > > > > --------------------------------------------------------------------- > > To unsubscribe, e-mail: dev-unsubscr...@maven.apache.org > > For additional commands, e-mail: dev-h...@maven.apache.org > > --------------------------------------------------------------------- > To unsubscribe, e-mail: dev-unsubscr...@maven.apache.org > For additional commands, e-mail: dev-h...@maven.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: dev-unsubscr...@maven.apache.org For additional commands, e-mail: dev-h...@maven.apache.org
