Tooling
Go 1.26 rebuilt go fix on the analysis framework. It modernizes your code and respects the Go version your module declares. The post covers the modernizers, the bigger x/tools suite, and what //go:fix inline can and can't migrate.
How cmd/go's script tests led me to testscript, and how to use it for CLI tests that exercise argv, stdout, stderr, exit codes, and scratch files.
txtar is a tiny plain-text archive format Russ Cox introduced in 2018 for multi-file test fixtures. The Go Playground, cmd/go's script tests, gopls's marker tests, and rsc.io/rf all reach for it.