third_party: goimports: apply import grouping patch
This allows developers to build //:goimports and point their IDE/editor
to it to easily conform to the import style guide.
We also document how to run this tool in CODING_STANDARDS.md.
Integration with IntelliJ is TBD.
Change-Id: I61e412162e51e513ec5888eda5221c9d145b6454
Reviewed-on: https://review.monogon.dev/c/monogon/+/493
Reviewed-by: Leopold Schabel <leo@nexantic.com>
diff --git a/third_party/go/patches/goimports-group-merging.patch b/third_party/go/patches/goimports-group-merging.patch
new file mode 100644
index 0000000..ed87faf
--- /dev/null
+++ b/third_party/go/patches/goimports-group-merging.patch
@@ -0,0 +1,152 @@
+Upstream CL: https://go-review.googlesource.com/c/tools/+/321409
+
+From cdd84f3789f3ebbd1c55dc220bbbe4a77ab4024a Mon Sep 17 00:00:00 2001
+From: Moekr <1143757638wlw@gmail.com>
+Date: Thu, 20 May 2021 15:41:17 +0800
+Subject: [PATCH] internal/imports: merge mergeable import groups
+
+Merge two import groups if there is no comments between them.
+This can make import blocks look more pretty.
+
+Fixes golang/go#20818 golang/go#28200
+
+Change-Id: Ic02ca83bd778e6d5b5b3c15292cde4fba6c842a9
+---
+ internal/imports/fix_test.go | 65 +++++++++++++++++++++++++++++----
+ internal/imports/sortimports.go | 23 ++++++++++--
+ 2 files changed, 77 insertions(+), 11 deletions(-)
+
+diff --git a/internal/imports/fix_test.go b/internal/imports/fix_test.go
+index 005bf96e..5ff84cdd 100644
+--- a/internal/imports/fix_test.go
++++ b/internal/imports/fix_test.go
+@@ -553,7 +553,6 @@ c = fmt.Printf
+
+ import (
+ "fmt"
+-
+ "gu"
+
+ "manypackages.com/packagea"
+@@ -644,15 +643,11 @@ var _, _, _, _, _ = fmt.Errorf, io.Copy, strings.Contains, renamed_packagea.A, B
+
+ import (
+ "fmt"
+-
+- renamed_packagea "manypackages.com/packagea"
+-
+ "io"
+-
+- . "manypackages.com/packageb"
+-
+ "strings"
+
++ renamed_packagea "manypackages.com/packagea"
++ . "manypackages.com/packageb"
+ _ "manypackages.com/packagec"
+ )
+
+@@ -1151,6 +1146,62 @@ var _, _ = rand.Read, rand.NewZipf
+ import "math/rand"
+
+ var _, _ = rand.Read, rand.NewZipf
++`,
++ },
++ {
++ name: "comment_between_imports_simple",
++ in: `package main
++
++import (
++ _ "foo2"
++ // foo3 has side effects.
++ _ "foo3"
++ _ "foo1"
++)
++`,
++ out: `package main
++
++import (
++ _ "foo2"
++ // foo3 has side effects.
++ _ "foo1"
++ _ "foo3"
++)
++`,
++ },
++ {
++ name: "comment_between_imports_complex",
++ in: `package main
++
++import (
++ _ "foo1" // foo1, "std" package
++ _ "github.com/bar/foo1" // github.com/bar/foo1, third-party package
++ _ "local/foo1" // local/foo1, local package
++
++ _ "appengine"
++
++ _ "foo2"
++ // local/foo3 comment
++ _ "local/foo3"
++ _ "github.com/bar/foo2"
++)
++`,
++ out: `package main
++
++import (
++ _ "foo1" // foo1, "std" package
++ _ "foo2"
++ _ "local/foo1" // local/foo1, local package
++
++ _ "github.com/bar/foo1" // github.com/bar/foo1, third-party package
++
++ _ "appengine"
++
++ // local/foo3 comment
++ _ "local/foo3"
++
++ _ "github.com/bar/foo2"
++)
+ `,
+ },
+ }
+diff --git a/internal/imports/sortimports.go b/internal/imports/sortimports.go
+index be8ffa25..25c5ca3f 100644
+--- a/internal/imports/sortimports.go
++++ b/internal/imports/sortimports.go
+@@ -34,14 +34,29 @@ func sortImports(localPrefix string, fset *token.FileSet, f *ast.File) {
+ continue
+ }
+
++ // Find comments.
++ commentLines := make([]int, len(f.Comments))
++ for j, comment := range f.Comments {
++ commentLines[j] = fset.Position(comment.Pos()).Line
++ }
++
+ // Identify and sort runs of specs on successive lines.
+ 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(localPrefix, fset, f, d.Specs[i:j])...)
+- i = j
++ if j > i {
++ curLine, prevLine := fset.Position(s.Pos()).Line, fset.Position(d.Specs[j-1].End()).Line
++ if curLine > 1+prevLine {
++ // j begins a new run.
++ for _, commentLine := range commentLines {
++ if prevLine < commentLine && commentLine < curLine {
++ // End this one if there is a comment before the new one.
++ specs = append(specs, sortSpecs(localPrefix, fset, f, d.Specs[i:j])...)
++ i = j
++ break
++ }
++ }
++ }
+ }
+ }
+ specs = append(specs, sortSpecs(localPrefix, fset, f, d.Specs[i:])...)
+--
+2.31.1
+