+1. We already have Gradle in our build process, it'd be great to make it first class.
On Wed, Apr 29, 2026 at 11:06 AM Josh McKenzie <[email protected]> wrote: > *Plus.* > *One.* > > On Tue, Apr 28, 2026, at 7:22 PM, David Capwell wrote: > > I'd like to propose adding Gradle build support to the project. This is > not a proposal to remove ant -- ant remains the primary build system. The > patch (PR #4778) adds gradle as an opt-in developer tool that sources its > configuration from ant's build.xml, layering gradle's task graph and > caching on top of what we already have. > > **What the patch does** > > Gradle wraps ant's existing configuration. You maintain ant as before; > gradle reads from it. The result is a developer experience layer on top of > our current build: > > ``` > $ ./gradlew test --tests org.apache.cassandra.utils.UUIDTest --rerun > BUILD SUCCESSFUL in 2s > 27 actionable tasks: 1 executed, 26 up-to-date > ``` > > Compare this to the correct way to run a single test via ant that matches > what CI actually executes and doesn't rebuild unneeded work: > > ``` > $ # human validates that the cache is still valid... did you change the > JDK? Did any file change? Human must maintain this in their head > $ ant -Dant.gen-doc.skip=true \ > -Dno-checkstyle=true \ > -Dant.gen-doc.skip=true \ > -Drat.skip=true \ > -Dno-build-test=true \ > testclasslist \ > -Dtest.timeout=480000 \ > -Dtest.classlistprefix=unit \ > -Dtest.classlistfile=<(echo org/apache/cassandra/utils/UUIDTest.java) > ``` > > Most developers use `ant test-some` instead because of this complexity, > but `test-some` uses different JVM arguments than `testclasslist` (which is > what CI runs). This means test failures in CI may not reproduce locally > because the developer ran the test differently. With gradle there is one > way to run a test; local and CI do not have different behaviors. > > **Why Gradle and not Maven** > > This question has come up in every prior discussion, so let me address it > directly. > > 1. **The ecosystem already chose Gradle.** Accord, Sidecar, and Analytics > are all Gradle projects. Choosing Maven for the server would mean three > subprojects on Gradle and one on Maven. Accord integration is the clearest > example of the problem: today, ant works around Accord being a Gradle > project by having Accord *publish* artifacts to the user's local Maven > repository, then ant resolves them from there. Maven would have the same > problem -- it would also need Accord to publish locally before the server > build can proceed. With Gradle, there's no publish step at all. Gradle > understands how to build Accord directly via composite builds: > > ```groovy > includeBuild('modules/accord') { > dependencySubstitution { > substitute module('org.apache.cassandra:cassandra-accord') > using project(':accord-core') > } > } > ``` > > Gradle builds Accord from source as part of the server build. No > intermediate publish, no stale local artifacts, no coordination. > > 2. **Maven forces us into its model; Gradle lets us keep ours.** Over the > years with ant we've grown a number of custom solutions to problems -- > custom test execution, custom artifact assembly, custom dependency > handling. These work for us. Maven's opinionated structure (one artifact > per POM, standard lifecycle phases, rigid directory layout) would require > us to restructure the project to fit Maven's expectations. We'd be fighting > the tool. Gradle lets us express our existing custom workflows naturally > while still benefiting from a modern build system's caching, dependency > resolution, and task graph. > > 3. **Maven can't wrap ant.** The approach in this patch -- gradle sourcing > ant's config so we incrementally adopt without a big-bang rewrite -- isn't > possible with Maven. A Maven migration would require rewriting build > configuration from scratch, which is exactly the kind of disruption that > has killed every prior proposal on this mailing list. > > 4. **Incremental builds are first-class in Gradle.** Maven's incremental > story requires plugins and is unreliable in practice. Gradle's task > avoidance and build cache are core features. > > 5. **Gradle version stability -- an honest assessment.** The concern about > Gradle version churn is legitimate. We pin a specific version via the > wrapper (Gradle 9 in this patch), so day-to-day there is no drift. However, > when we do need to upgrade -- for example, to pick up JDK support for a new > Java version -- there is real risk of breaking changes requiring work. If > we release annually, we may need to update Gradle annually, and that could > require effort. > > Two things that mitigate this: First, Gradle has improved its > deprecation cycle -- they warn for a full major version before removing > APIs, giving upgrade windows. This patch already addressed Accord's Gradle > 8 to 9 migration, which involved deprecation warnings (not breakage) that > will become errors in 10.x. Second, AI tooling dramatically lowers the > migration cost. This patch itself was written by Claude opus and it had no > issues understanding Gradle's conventions and generating the correct > configuration. Future version upgrades are well-suited to the same approach > -- the tool reads the migration guide, reads our config, and produces the > update. > > **Maintenance cost** > > I want to be clear-eyed about this: "gradle sources ant" means there is > minimal maintenance overhead *for the current project structure*. If we had > this patch 5 years ago, there would have been zero drift in that time. But > it's not zero-maintenance in all scenarios -- if we want to do larger > structural changes (splitting into multiple modules, reorganizing source > sets), both systems would need updates. For the day-to-day reality of how > the project evolves, though, the cost is very low. > > **The long-term path** > > If gradle proves itself I foresee that we eventual rely on gradle as the > source of truth for builds and we update ant to delegate to gradle. If the > community eventually feels that gradle is getting in our way its isolated > and able to revert; so very low risk. > > **What's in this patch and what isn't** > > The patch covers the core developer loop: > > - Main source compilation with correct JDK flags and `--add-exports` > - Dependency resolution from existing POM files > - ANTLR 3 and JFlex code generation > - Unit, long, burn, distributed, and simulator test suites with correct > JDK-specific JVM args > - All 5 test variants (compression, cdc, latest, oa, > system-keyspace-directory) > - Checkstyle (main + test) > - Main JAR and simulator JARs > - Accord composite build (no local publish step) > > What's not covered yet: > > | Category | What's Missing | > |---|---| > | Packaging | stress.jar, fqltool.jar, sstableloader.jar, dtest-jar, > sources-jar, javadoc-jar | > | Release | bin/src tarballs, checksums, dist directory assembly | > | Publishing | Maven local install and remote deploy with signing | > | Test suites | upgrade dtests, memory tests, stress/fqltool/sstableloader > tests, CQL-specific tests | > | Code coverage | JaCoCo integration | > | Documentation | Javadoc, Asciidoc/Antora | > | Benchmarks | JMH microbench | > | Static analysis | Apache RAT license check | > | Security scanning | OWASP, SonarQube | > > This is roughly 52% of ant's total logical outcomes. The intentional > scoping choice was: cover what developers actually use daily, get buy-in on > the approach, then fill in the rest. I'm happy to add any of the above -- > particularly release/publishing support -- once the direction is agreed. > None of these are architecturally difficult; they're just additional tasks > to wire up. > > **Patch details** > > - JIRA: https://issues.apache.org/jira/browse/CASSANDRA-21344 > - PR: https://github.com/apache/cassandra/pull/4778 > > Looking forward to feedback. > > --- > > **Prior mailing list discussions referenced:** > > - "[DISCUSS] Build tool" (Feb 2022) -- Aleksei Zotov's proposal to migrate > from ant > - "RFC try for s/ant/gradle/" (Sep 2014) -- Robert Stupp's original Gradle > proposal and prototype > - "[discuss] Modernization of Cassandra build system" (Jun 2015) > - "[DISCUSS] CASSANDRA-17750: Security migration away from Maven Ant > Tasks" (Aug 2022) > - "Any plan to migrate from Ant to Maven?" (May 2020) > > >
