Migrating Twitter's monorepo from Pants to Bazel
summary
Twitter migrates its monorepo Source (20 million hand‑crafted lines and ~10× generated code, mostly Scala, plus Java, Python, NodeJS, Go and C/C++) from Pants to Bazel. Migration uses a translation layer that maps each Pants target to Bazel macros and loads them in Bazel prelude so existing build files run unchanged; a pilot proves some teams use Bazel daily and are happy. Remaining hard work centers on dependency resolution — experimenting with designs to support multiple incompatible versions across ~2,000 engineers.
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chapters (7)
- 0:00Monorepo migration intro
- 1:44Why Twitter’s monorepo is large
- 2:47Pants versus Bazel differences
- 5:16Gradual migration strategy
- 8:11Handling model differences
- 10:20Next steps for teams
- 14:53Acknowledgments
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