x/tools/cmd/goimports: incorrectly adds imports for variables that match package names

[cep21]

Please see the following console output as a test case. log is a varaible defined in another file and therefor does not need a package import. The expected behavior is for goimports to detect no issues.

11:19:35 jack@Jacks-MacBook-Pro.local:/tmp/b
< go get -u golang.org/x/tools/cmd/goimports
11:20:02 jack@Jacks-MacBook-Pro.local:/tmp/b
< ls -la
total 16
drwxr-xr-x   4 jack  wheel   136B Oct 22 11:18 .
drwxrwxrwt  32 root  wheel   1.1K Oct 22 11:17 ..
-rw-r--r--   1 jack  staff   111B Oct 22 11:18 a.go
-rw-r--r--   1 jack  staff    82B Oct 22 11:18 a_test.go
11:20:05 jack@Jacks-MacBook-Pro.local:/tmp/b
< cat a.go 
package main

import "github.com/Sirupsen/logrus"

var log *logrus.Logger

func init() {
    log = logrus.New()
}
11:20:07 jack@Jacks-MacBook-Pro.local:/tmp/b
< cat a_test.go 
package main

import "testing"

func TestB(t *testing.T) {
    log.Printf("Hello")
}
11:20:09 jack@Jacks-MacBook-Pro.local:/tmp/b
< goimports -d .
diff a_test.go gofmt/a_test.go
--- /var/folders/5r/x8pdxnqs0sdg7w_262278m800000gn/T/gofmt282742701 2015-10-22 11:20:12.000000000 -0700
+++ /var/folders/5r/x8pdxnqs0sdg7w_262278m800000gn/T/gofmt424960296 2015-10-22 11:20:12.000000000 -0700
@@ -1,6 +1,9 @@
 package main

-import "testing"
+import (
+   "log"
+   "testing"
+)

 func TestB(t *testing.T) {
    log.Printf("Hello")

[ianlancetaylor]

I think we're probably going to have to chalk this up to heuristic failure, but if somebody can figure out a good fix, by all means go for it.

[cep21]

In my case, an option to reorder imports but not add new ones would do.

[mdempsky]

@cep21 gofmt reorders imports without adding/removing them. Does that do what you want?

[cep21]

I don't currently see that behavior in go1.5.1. Is it new?

[mdempsky]

I don't think so. These cmd/gofmt test files haven't changed in 2+ years:

https://github.com/golang/go/blob/master/src/cmd/gofmt/testdata/import.input
https://github.com/golang/go/blob/master/src/cmd/gofmt/testdata/import.golden

[cep21]

I don't observe gofmt reordering imports like goimports

15:24:59 jack@Jacks-MacBook-Pro.local:/tmp/b
< cat a.go 
package main

import (
    "fmt"
    "github.com/Sirupsen/logrus"
)

var log *logrus.Logger

func init() {
    log = logrus.New()
    fmt.Printf("Hello world")
}
15:25:02 jack@Jacks-MacBook-Pro.local:/tmp/b
< goimports -d a.go
diff a.go gofmt/a.go
--- /var/folders/5r/x8pdxnqs0sdg7w_262278m800000gn/T/gofmt609869718 2015-10-22 15:25:05.000000000 -0700
+++ /var/folders/5r/x8pdxnqs0sdg7w_262278m800000gn/T/gofmt029612029 2015-10-22 15:25:05.000000000 -0700
@@ -2,6 +2,7 @@

 import (
    "fmt"
+
    "github.com/Sirupsen/logrus"
 )

15:25:05 jack@Jacks-MacBook-Pro.local:/tmp/b
< gofmt -s -d a.go 
15:25:08 jack@Jacks-MacBook-Pro.local:/tmp/b

[mdempsky]

Ah, I suppose gofmt doesn't separate stdlib imports from third-party imports like goimports does. If you separate them yourself, it should still sort contiguous runs of imports.

[mdempsky]

@ianlancetaylor Maybe goimports could run go/types on the AST and only consider ast.Idents that don't resolve to a variable/const/function/type?

[bradfitz]

Dup of #7463