RFC: Automatically generated BuildRequires for maven-based Java projects

Good $LOCAL_TIME_OF_DAY, I've been working on experimental support for automatically generating BuildRequires for maven-based Java projects, and it's now available for testing in rawhide (and in fedora 32, for local testing). There's no "macro support" for this yet, because it's still work-in-progress, though when it proves useful support for it might eventually get merged into the Java packaging macros directly. The good new is: it should basically "just work" if your package isn't doing anything weird, but this is Java we're talking about, so there's at least three limitations I can think of right now (the bad news): 1. no built-in blacklist for irrelevant plugins yet (e.g. maven-release-plugin) 2. no support for different profiles yet 3. no support for plugins that add additional dependencies in their configuration There are workarounds for the first two limitations: 1. It's pretty easy to just disable those plugins manually in %prep with "%pom_remove_plugin :maven-foo-plugin". 2. If you know ahead of time which submodules will get activated (e.g. based on a previous package build), just specify those modules on the mvn-genbr command line instead of letting mvn-genbr fail to find them. 3. just continue to specify those non-discoverable dependencies manually Usage in .spec files should be pretty simple, and similar to how other tools handle generated BuildRequires: - replace all java / "mvn(foo:bar)" dependencies with "BuildRequires: mvn-genbr", - but keep "BuildRequires: maven-local" (this is not automatically generated). - keep your "pom.xml" modifications in %prep, as usual (e.g. removing unnecessary maven plugins, changing dependencies, modifying XML with XPath queries) - add the following section to your .spec after %prep: %generate_buildrequires mvn-genbr -t . If you're not running the test suite (%mvn_build -f), then drop the -t / --with-tests flag. If the root directory of the maven project is not the toplevel directory, specify the name of the root directory / directories instead of "." (mvn-genbr accepts multiple arguments for this purpose. use "mvn-genbr --help" for current list of command line options). If you want to check out what automatic dependencies mvn-genbr will generate for your package, you can try it without kicking off a package build by dnf-installing "mvn-genbr" (available fedora 32+), and running it with the same arguments as in your .spec file in the source directory that's generated and processed by "fedpkg prep". Comparisons between the generated dependency lists and those that were curated "manually" would be of interest, especially for bug reports :) Since this is still work-in-progress (though it works for a few simple packages I tried it with), please feel free to report your experiences, and - more importantly - open issues when the tool either crashes (it shouldn't, since the POM parser successfully parsed all non-broken maven project files from all fedora packages), or when it generates too many (not that problematic) or too few (not so good) dependencies. The code for the POM parser and mvn-genbr lives in this project on pagure: https://pagure.io/ironthree/pommes Go forth and break my code! Fabio