x/tools/cmd/goimports: missing import alias

[vearutop]

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

$ go version
go version go1.11.5 darwin/amd64

Does this issue reproduce with the latest release?

Yes

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

go env Output

$ go env
GOARCH="amd64"
GOBIN=""
GOCACHE="/Users/viacheslav.poturaev/Library/Caches/go-build"
GOEXE=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="darwin"
GOOS="darwin"
GOPATH="/Users/viacheslav.poturaev/go"
GOPROXY=""
GORACE=""
GOROOT="/usr/local/Cellar/go/1.11.4/libexec"
GOTMPDIR=""
GOTOOLDIR="/usr/local/Cellar/go/1.11.4/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/lb/j0gz8jln36z4frqkrzmkdb0c0000gp/T/go-build387979460=/tmp/go-build -gno-record-gcc-switches -fno-common"

What did you do?

After go get -u golang.org/x/tools/cmd/goimports.
Having a file.go with

import "github.com/bla/updater-go"

I'm running goimports -w file.go.

What did you expect to see?

import updater "github.com/bla/updater-go"

What did you see instead?

import "github.com/bla/updater-go"

Not long ago goimports started adding aliases in case package name differs from import path, with recent update that seem to be reverted.

[puellanivis]

This was an intentional reversion to prior behavior: #29556

[vearutop]

#29556 is likely to be relevant, I tried with different imports:

	“github.com/acme/stats-go”
	uuid “github.com/acme/go.uuid”

and got uuid added because go does not match package name uuid, while stats-go does match stats package name after non-identifier rune cut off.

[ianthehat]

This was an intentional change.
We decided that goimports was adding a local alias in cases where the name was easy to determine from a simple rule, in cases where the base name is not valid as a package name.
RIght now the rules are, any trailing path fragments that look like versions are dropped.
The last remaining fragment is examined, if it starts with go- then that bit is dropped.
If the remains contains a character that would not be valid in an identifier, then only the part before that character is considered.
If what we have left matches the internal name, then no local alias is added, otherwise one is.

[hiromaily]

@ianthehat
As you mentioned, goimports added many aliases but it affects many our source code and it's not readable for us because we are used to previous code without alias.
Is there any way to prevent alias addition functionality??