x/tools/cmd/goimports: format is not the same

[tomocy]

What version of Go are you using (go version)?

$ go version
go version go1.12.5 darwin/amd64

Does this issue reproduce with the latest release?

Yes in 1.12.5

What operating system and processor architecture are you using (go env)?

go env Output

$ go env
GOARCH="amd64"
GOBIN="/Users/tomocy/Codes/bin"
GOCACHE="/Users/tomocy/Library/Caches/go-build"
GOEXE=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="darwin"
GOOS="darwin"
GOPATH="/Users/tomocy/Codes"
GOPROXY=""
GORACE=""
GOROOT="/usr/local/Cellar/go/1.12.5/libexec"
GOTMPDIR=""
GOTOOLDIR="/usr/local/Cellar/go/1.12.5/libexec/pkg/tool/darwin_amd64"
GCCGO="gccgo"
CC="clang"
CXX="clang++"
CGO_ENABLED="1"
GOMOD=""
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"
PKG_CONFIG="pkg-config"
GOGCCFLAGS="-fPIC -m64 -pthread -fno-caret-diagnostics -Qunused-arguments -fmessage-length=0 -fdebug-prefix-map=/var/folders/19/1v1v30rd7fn4vzqt6xf_2g580000gn/T/go-build769896193=/tmp/go-build -gno-record-gcc-switches -fno-common"

What did you do?

When one package is imported in one line

import "error"

I imported a package

import (
    "log"
    "error"
)

but, I stopped using the package after all and format with goimport.

What did you expect to see?

Import the first package in one line.

import "error"

What did you see instead?

Import the package with parenthesis.

import (
    "error"
)

[ALTree]

Thanks for the report.

This is an intentional goimports feature. It was introduced to fix #18051; essentially for two reasons: the fact that it minimizes diff noise when committing, and the fact that switching to the one-line format can misplace comments when there are commented lines between the lines with the packages names in the grouped version, if that is converted to the single-line version.

I'm closing here, since this is WAI.