Hi Sterling, This is certainly something we could consider for Groovy 6. That is currently where we'd like to put most of our focus, and where we have some nice performance improvements that could be of benefit to Gradle and other frameworks in the Groovy ecosystem. The current implementation chose a very specific way to handle all of the assignment operators, and this leads to simplicity and minimises edge cases across the variations: ADD_ASSIGN, SUB_ASSIGN, MUL_ASSIGN, DIV_ASSIGN, AND_ASSIGN, OR_ASSIGN, XOR_ASSIGN, MOD_ASSIGN, LSHIFT_ASSIGN, RSHIFT_ASSIGN, URSHIFT_ASSIGN, and ELVIS_ASSIGN.
The more backwards compatible the change is, the more likely it is we could backport, but we'll be ramping down focus on Groovy 4 soon and mostly attempting to handle critical bugs. Having said that, I am interested in others' thoughts. Cheers, Paul. On Sun, Mar 8, 2026 at 6:33 PM Sterling Greene <[email protected]> wrote: > Hey Groovy people. > > Groovy currently supports operators like a+=b by decomposing them into > a=a+b and + is implemented with a plus() method. Kotlin does something > similar. > > Kotlin also supports overloading "augmented assignments": > https://kotlinlang.org/docs/operator-overloading.html#augmented-assignments > which appears to just be another way of saying "assignment arithmetic > operators." In Kotlin, a type can implement plusAssign and plus and the > appropriate one will be selected depending on the scenario. > > My proposal is to add support in Groovy for these methods too. Groovy > would start calling plusAssign instead of decomposing into an assignment > and call to plus. There are details about fallbacks and differences between > static and dynamic Groovy, but I'm happy to provide those if this seems > like a reasonable idea. > > I would also be willing to implement this. > > My questions: > > Is this reasonable and what's the best way to discuss this further? > > Is it possible for this to be added to Groovy 4? > > The reason Groovy 4 is important to us is that Gradle 9 currently uses > Groovy 4. We want to make API changes in Gradle 10 and the current behavior > of += with FileCollections is causing some headaches. Getting support for > overloading += directly in Gradle 9 could make the API changes in Gradle 10 > less painful. > > Thanks! > > -- > > > Sterling Greene > > Senior Lead Software Engineer > > Gradle Technologies > gradle.com > [image: image.png] > > > *CONFIDENTIALITY NOTICE*: The contents of this email message, and any > attachments, are intended solely for the addressee(s) and may contain > confidential, proprietary and/or privileged information legally protected > from disclosure. If you are not the intended recipient of this > communication, or if you received this communication by mistake, please > notify the sender immediately and delete this message and any attachments. > If you are not the intended recipient, you are hereby notified that any > use, retransmission, dissemination, copying or storage of this message or > its attachments is strictly prohibited. >
