Go 1.25 Release Notes

Summary

Introduction to Go 1.25 The latest Go release, version 1.25, arrives in August 2025, six months after Go 1.24. Most of its changes are in the implementation of the toolchain, runtime, and libraries. As always, the release maintains the Go 1 promise of compatibility. We expect almost all Go programs to continue to compile and run as before. Changes to the language There are no languages changes that affect Go programs in Go 1.25. However, in the language specification the notion of core types has been removed in favor of dedicated prose. See the respective blog post for more information. Go command The go build -asan option now defaults to doing leak detection at program exit. This will report an error if memory allocated by C is not freed and is not referenced by any other memory allocated by either C or Go. These new error reports may be disabled by setting ASAN_OPTIONS=detect_leaks=0 in the environment when running the program. The Go distribution will include fewer prebuilt tool binaries. Core toolchain binaries such as the compiler and linker will still be included, but tools not invoked by build or test operations will be built and run by go tool as needed. The new go.mod ignore directive can be used to specify directories the go command should ignore. Files in these directories and their subdirectories will be ignored by the go command when matching package patterns, such as all or ./..., but will still be included in module zip files. The new go doc -http option will start a documentation server showing documentation for the requested object, and open the documentation in a browser window. The new go version -m -json option will print the JSON encodings of the runtime/debug.BuildInfo structures embedded in the given Go binary files. The go command now supports using a subdirectory of a repository as the path for a module root, when resolving a module path using the syntax <meta name="go-import" content="root-path vcs repo-url subdir"> to indicate that the roo...