🧩 Title:

How can I dynamically share and update Maven artifact versions across multiple MODULE.bazel files using Bzlmod?

📝 Description:

Hi Bazel team 👋

I’m currently working in a large Bazel monorepo where we useBzlmod andrules_jvm_external for dependency management.
We want to have asingle source of truth for dependency versions (e.g.,FIP_VERSION,SWAGGER_VERSION, etc.) that can be shared across multiple.MODULE.bazel files — for example:

/MODULE.bazel/third-party-deps/main-maven.MODULE.bazel

Both define Maven repositories and should stay in sync automatically.

💡 What we’ve tried so far

1. We created a centralversions.json file containing all artifact versions.

2. We implemented amodule extension that reads this JSON and prints the values:

   def_maven_versions_ext_impl(module_ctx):data=json.decode(module_ctx.read(module_ctx.path(module_ctx.attr.json_file)))print("✅ Loaded versions:",data)

   That part works — the extension can read the JSON and print dynamic versions.

3. We tried to reuse those versions in another.MODULE.bazel file by loading them like this:

   use_extension("//third-party-deps:maven_versions_ext.bzl","maven_versions_ext")maven_versions_ext.maven_versions(json_file="//:versions.json")use_repo(maven_versions_ext,"versions_repo")load("@versions_repo//:versions.bzl","version_json")

   However, that fails becauserepositories generated by a module extension are not visible during the same module evaluation phase.
   (We get:name 'versions_repo' is not defined or similar errors.)

4. We also tried variants using:

   • module_ctx.generate_repo()
   • repository_rule withuse_repo_rule()
   • Directly referencing JSON insidemaven.install(artifacts = "//:artifacts.json")

   But Bzlmod’s evaluation model prevents dynamic file loading during module evaluation.

❓ The question

Is there an officially supported or recommended way inBzlmod to:

• Define shared version data (e.g.,versions.json) once,
• Have it dynamically read and exported by a module extension,
• And make it accessible acrossmultiple MODULE.bazel files in the same monorepo?

Essentially:

How can multiple module files use the same dynamically generated repository or version constantswithout duplicating logic or hardcoding versions?

⚙️ Context

• Bazel version:7.x

• rules_jvm_external:6.5

• rules_spring / rules_kotlin / aspect_rules_js also used

• The goal is to have something like this:

  # in MODULE.bazeluse_extension("//third-party-deps:maven_versions_ext.bzl","maven_versions_ext")maven_versions_ext.maven_versions(json_file="//:versions.json")use_repo(maven_versions_ext,"versions_repo")

  # in another MODULE.bazeluse_extension("//third-party-deps:maven_versions_ext.bzl","maven_versions_ext")use_repo(maven_versions_ext,"versions_repo")load("@versions_repo//:versions.bzl","version_json")

But Bazel currently doesn’t seem to allow reading a generated repo in another module file in the same evaluation phase.

💬 Expected outcome

A supported pattern (or documentation reference) forsharing dynamically generated data (like Maven versions) between multiple.MODULE.bazel files using module extensions — without duplicating constants or breaking Bazel’s module loading order.

Would this be possible through:

• A new feature inmodule_ctx (e.g. exposing generated repos earlier)?
• A recommended Bazel-native pattern for shared configuration between multiple module files?
• Or is the only safe path to hardcode or script the version updates externally?

🙏 Thank you

Any guidance or official example on this kind of multi-MODULE shared state in Bzlmod would be greatly appreciated.
It would help a lot for large-scale monorepos managing dependency versions centrally.

—
Environment:

• macOS / Linux
• Bazel 7.x
• Usingrules_jvm_external,rules_kotlin,rules_js,rules_spring, etc.

Would you like me to make it slightly shorter and more “GitHub issue” friendly (i.e. fewer explanations, more condensed)?
That way you can copy-paste it directly into a GitHub issue.