container/heap: confusing claim of memory leak when shrinking slices #65403
Description
Go version
go version go1.21.1 openbsd/amd64
Output of go env in your module/workspace:
GO111MODULE=''
GOARCH='amd64'
GOBIN=''
GOCACHE='/home/richard/.cache/go-build'
GOENV='/home/richard/.config/go/env'
GOEXE=''
GOEXPERIMENT=''
GOFLAGS=''
GOHOSTARCH='amd64'
GOHOSTOS='openbsd'
GOINSECURE=''
GOMODCACHE='/home/richard/go/pkg/mod'
GONOPROXY=''
GONOSUMDB=''
GOOS='openbsd'
GOPATH='/home/richard/go'
GOPRIVATE=''
GOPROXY='https://proxy.golang.org,direct'
GOROOT='/usr/local/go'
GOSUMDB='sum.golang.org'
GOTMPDIR=''
GOTOOLCHAIN='auto'
GOTOOLDIR='/usr/local/go/pkg/tool/openbsd_amd64'
GOVCS=''
GOVERSION='go1.21.1'
GCCGO='gccgo'
GOAMD64='v1'
AR='ar'
CC='cc'
CXX='c++'
CGO_ENABLED='1'
GOMOD='/dev/null'
GOWORK=''
CGO_CFLAGS='-O2 -g'
CGO_CPPFLAGS=''
CGO_CXXFLAGS='-O2 -g'
CGO_FFLAGS='-O2 -g'
CGO_LDFLAGS='-O2 -g'
PKG_CONFIG='pkg-config'
GOGCCFLAGS='-fPIC -m64 -pthread -fno-caret-diagnostics -Qunused-arguments -Wl,--no-gc-sections -fmessage-length=0 -ffile-prefix-map=/tmp/go-build50129197=/tmp/go-build -gno-record-gcc-switches'What did you do?
I read the "PriorityQueue" example of the container/heap documentation.
What did you see happen?
I came across this line, claiming to prevent a memory leak. It confused, me since I've never heard of a memory leak caused by Go slices.
Upon some pondering, I figured that the author of this line is talking about the memory, that is retained when shrinking a slice. However, I think the term "memory leak" is not right for this, since the memory will be freed once the slice becomes unused or it will be reused when the slice grows again. At most, I would call this a "space leak".
What did you expect to see?
I would prefer this line to be absent. It seems like a premature optimization to me and doesn't help explaining the container/heap package.