Revert "imports: support repairing import grouping/ordering"

This reverts commit CL 116795 12a7c317e894c0a622b5ed27f0a102fcdd56d1ad.

Reason for revert: mangles comments in imports. See comments
on issue golang/go#20818.

Updates golang/go#20818

Change-Id: Iff82f8dc310dceb982b48d82b26176ea279fef10
Reviewed-on: https://go-review.googlesource.com/c/144339
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>

imports/fix_test.go

@@ -514,6 +514,7 @@ c = fmt.Printf
 
 import (
 	"fmt"
+
 	"gu"
 
 	"github.com/foo/bar"
@@ -604,11 +605,15 @@ var _, _, _, _, _ = fmt.Errorf, io.Copy, strings.Contains, renamed_bar.A, B
 
 import (
 	"fmt"
-	"io"
-	"strings"
 
 	renamed_bar "github.com/foo/bar"
+
+	"io"
+
 	. "github.com/foo/baz"
+
+	"strings"
+
 	_ "github.com/foo/qux"
 )
 
@@ -1044,149 +1049,6 @@ var _ = fmt.Printf
 `,
 	},
 
-	// golang.org/issue/20818
-	{
-		name: "sort_all_groups",
-		in: `package p
-import (
-	"testing"
-
-	"github.com/Sirupsen/logrus"
-	"context"
-)
-
-var _, _, _ = testing.T, logrus.Entry, context.Context
-`,
-		out: `package p
-
-import (
-	"context"
-	"testing"
-
-	"github.com/Sirupsen/logrus"
-)
-
-var _, _, _ = testing.T, logrus.Entry, context.Context
-`,
-	},
-
-	// golang.org/issue/20818
-	{
-		name: "sort_many_groups",
-		in: `package p
-import (
-	"testing"
-	"k8s.io/apimachinery/pkg/api/meta"
-
-	"fmt"
-	"github.com/pkg/errors"
-
-	"golang.org/x/tools/cover"
-
-	"github.com/sirupsen/logrus"
-	"context"
-)
-
-var _, _, _, _, _, _ = testing.T, logrus.Entry, context.Context, meta.AnyGroup, fmt.Printf, errors.Frame
-`,
-		out: `package p
-
-import (
-	"context"
-	"fmt"
-	"testing"
-
-	"github.com/pkg/errors"
-	"github.com/sirupsen/logrus"
-	"k8s.io/apimachinery/pkg/api/meta"
-)
-
-var _, _, _, _, _, _ = testing.T, logrus.Entry, context.Context, meta.AnyGroup, fmt.Printf, errors.Frame
-`,
-	},
-
-	// golang.org/issue/20818
-	{
-		name: "sort_all_groups_with_blanks_and_comments",
-		in: `package p
-import (
-
-
-	"testing"
-	"k8s.io/apimachinery/pkg/api/meta"
-
-	// a comment for the "fmt" package (#26921: they are broken, should be fixed)
-	"fmt"
-	"github.com/pkg/errors" // some comment
-
-
-	"golang.org/x/tools/cover"
-
-	"github.com/sirupsen/logrus"
-	"context"
-
-
-)
-
-var _, _, _, _, _, _ = testing.T, logrus.Entry, context.Context, meta.AnyGroup, fmt.Printf, errors.Frame
-`,
-		out: `package p
-
-import (
-	"context"
-	"fmt"
-	"testing"
-
-	"github.com/pkg/errors" // some comment
-	"github.com/sirupsen/logrus"
-	"k8s.io/apimachinery/pkg/api/meta" // a comment for the "fmt" package (#26921: they are broken, should be fixed)
-)
-
-var _, _, _, _, _, _ = testing.T, logrus.Entry, context.Context, meta.AnyGroup, fmt.Printf, errors.Frame
-`,
-	},
-
-	{
-		name: "sort_all_groups_with_local_packages",
-		in: `package p
-import (
-	"local/foo"
-	"testing"
-	"k8s.io/apimachinery/pkg/api/meta"
-
-	"fmt"
-	"github.com/pkg/errors"
-
-	"github.com/local/bar"
-	"golang.org/x/tools/cover"
-
-	"github.com/sirupsen/logrus"
-	"context"
-)
-
-var _, _, _, _, _, _ = testing.T, logrus.Entry, context.Context, meta.AnyGroup, fmt.Printf, errors.Frame
-var _, _ = foo.Foo, bar.Bar
-`,
-		out: `package p
-
-import (
-	"context"
-	"fmt"
-	"testing"
-
-	"github.com/pkg/errors"
-	"github.com/sirupsen/logrus"
-	"k8s.io/apimachinery/pkg/api/meta"
-
-	"github.com/local/bar"
-	"local/foo"
-)
-
-var _, _, _, _, _, _ = testing.T, logrus.Entry, context.Context, meta.AnyGroup, fmt.Printf, errors.Frame
-var _, _ = foo.Foo, bar.Bar
-`,
-	},
-
 	{
 		name: "cryptorand_preferred_easy_possible",
 		in: `package p

imports/sortimports.go

@@ -34,8 +34,18 @@ func sortImports(fset *token.FileSet, f *ast.File) {
 			continue
 		}
 
-		// Sort and regroup all imports.
+		// Identify and sort runs of specs on successive lines.
-		sortSpecs(fset, f, d.Specs)
+		i := 0
+		specs := d.Specs[:0]
+		for j, s := range d.Specs {
+			if j > i && fset.Position(s.Pos()).Line > 1+fset.Position(d.Specs[j-1].End()).Line {
+				// j begins a new run.  End this one.
+				specs = append(specs, sortSpecs(fset, f, d.Specs[i:j])...)
+				i = j
+			}
+		}
+		specs = append(specs, sortSpecs(fset, f, d.Specs[i:])...)
+		d.Specs = specs
 
 		// Deduping can leave a blank line before the rparen; clean that up.
 		if len(d.Specs) > 0 {