rules-jvm-external provides an override mechanism that allows to switch out a group and artifact id with another dependency label. This features allows overriding dependencies that are brought in transitively (ie these dependencies are dragged in through top level dependencies referenced in bazel build files). pomgen honors the same override mechanism.
The library in this example depends on org.antlr:ST4 (@antlr//:org_antlr_ST4). This jar in turn drags in 3 transitives (the transitive closure is):
org.antlr:antlr-runtimereferencesorg.antlr:stringtemplatereferencesantlr:antlr
Generate a pom.xml file for this example's library:
bazel run @pomgen//:pomgen -- --package examples/dep-overrides --destdir /tmp/overrides
Have a look at the generated pom.xml - note that the pom brings in the transitives listed above.
On order to override dependencies brought in transitively, pomgen needs to be pointed to one or more "overrides" file(s). Add to the [general] section of the root .pomgenrc:
override_file_paths=examples/dep-overrides/overrides.bzl
The content of the overrides file is:
"org.antlr:stringtemplate": "@maven//:com_google_guava_guava"
(although this example only has a single override, many override rules are allowed)
This means that the stringtemplate dependency will be overridden with guava. Note that Guave happens to be defined in a different maven install rule (@maven instead of @antlr): overrides may cross maven install boundaries.
Regenerate the pom:
bazel run @pomgen//:pomgen -- --package examples/dep-overrides --destdir /tmp/overrides
Have a look at the generated pom.xml - since the stringtemplate dependency is replaced by guava, the antlr dependency, previously dragged in by stringtemplate, is no longer there.