mutate

Overview ¶

Command mutate runs mutation testing over the lines a branch changed: it applies one small fault at a time (an operator flipped, a condition forced, a statement removed) to the Go files changed since a base commit, runs the tests of the mutated file's package, and reports every mutant the tests do not catch.

go run ./tools/mutate -base origin/main [-workers 3] [-pkgs ./pkg/...] [-run regexp]

A mutant that does not compile is not counted. A surviving mutant is either a missing test or code whose effect no test can observe (dead, redundant or performance-only); each one needs one or the other answer.