Introduce gci as new linter

Signed-off-by: Xiang Dai <long0dai@foxmail.com>

Author: daixiang0

.golangci.example.yml

@@ -109,6 +109,10 @@ linters-settings:
   funlen:
     lines: 60
     statements: 40
+  gci:
+    # put imports beginning with prefix after 3rd-party packages;
+    # only support one prefix
+    local-prefixes: github.com/org/project
   gocognit:
     # minimal code complexity to report, 30 by default (but we recommend 10-20)
     min-complexity: 10

.golangci.yml

@@ -14,6 +14,8 @@ linters-settings:
   funlen:
     lines: 100
     statements: 50
+  gci:
+    local-prefixes: github.com/golangci/golangci-lint
   goconst:
     min-len: 2
     min-occurrences: 2

pkg/config/config.go

@@ -155,6 +155,9 @@ type Run struct {
 }
 
 type LintersSettings struct {
+	Gci struct {
+		LocalPrefixes string `mapstructure:"local-prefixes"`
+	}
 	Govet  GovetSettings
 	Golint struct {
 		MinConfidence float64 `mapstructure:"min-confidence"`

pkg/golinters/gci.go

@@ -0,0 +1,69 @@
+package golinters
+
+import (
+	"sync"
+
+	"github.com/daixiang0/gci/pkg/analyzer"
+	"github.com/daixiang0/gci/pkg/gci"
+	"github.com/golangci/golangci-lint/pkg/golinters/goanalysis"
+	"github.com/golangci/golangci-lint/pkg/lint/linter"
+	"github.com/pkg/errors"
+	"golang.org/x/tools/go/analysis"
+	"golang.org/x/tools/imports"
+)
+
+func NewGci() *goanalysis.Linter {
+	var mu sync.Mutex
+	var resIssues []goanalysis.Issue
+
+	analyzer := analyzer.Analyzer
+
+	return goanalysis.NewLinter(
+		analyzer.Name,
+		analyzer.Doc,
+		analyzer.Requires,
+		nil,
+	).WithContextSetter(func(lintCtx *linter.Context) {
+		localFlag := lintCtx.Settings().Gci.LocalPrefixes
+		analyzer.Run = func(pass *analysis.Pass) (interface{}, error) {
+			var fileNames []string
+			for _, f := range pass.Files {
+				pos := pass.Fset.PositionFor(f.Pos(), false)
+				fileNames = append(fileNames, pos.Filename)
+			}
+
+			var issues []goanalysis.Issue
+			for _, f := range fileNames {
+				diff, err := gci.Run(f, &gci.FlagSet{LocalFlag: localFlag})
+				if err != nil {
+					return nil, err
+				}
+
+				if diff == nil {
+					continue
+				}
+
+				is, err := extractIssuesFromPatch(string(diff), lintCtx.Log, lintCtx, analyzer.Name)
+				if err != nil {
+					return nil, errors.Wrapf(err, "can't extract issues from gci diff output %q", string(diff))
+				}
+
+				for i := range is {
+					issues = append(issues, goanalysis.NewIssue(&is[i], pass))
+				}
+			}
+
+			if len(issues) == 0 {
+				return nil, nil
+			}
+
+			mu.Lock()
+			resIssues = append(resIssues, issues...)
+			mu.Unlock()
+
+			return nil, nil
+		}
+	}).WithIssuesReporter(func(*linter.Context) []goanalysis.Issue {
+		return resIssues
+	}).WithLoadMode(goanalysis.LoadModeSyntax)
+}

pkg/lint/lintersdb/manager.go

@@ -206,6 +206,9 @@ func (m Manager) GetAllSupportedLinterConfigs() []*linter.Config {
 			WithPresets(linter.PresetStyle).
 			WithLoadForGoAnalysis().
 			WithURL("https://github.com/denis-tingajkin/go-header"),
+		linter.NewConfig(golinters.NewGci()).
+			WithLoadForGoAnalysis().
+			WithURL("https://github.com/daixiang0/gci"),
 		linter.NewConfig(golinters.NewMaligned()).
 			WithLoadForGoAnalysis().
 			WithPresets(linter.PresetPerformance).

test/testdata/gci.go

@@ -0,0 +1,13 @@
+//args: -Egci
+//config: linters-settings.gci.local-prefixes=github.com/golangci/golangci-lint
+package testdata
+
+import (
+	"fmt" // ERROR "File is not `goimports`-ed"
+	"github.com/golangci/golangci-lint/pkg/config"
+)
+
+func Bar() {
+	fmt.Print("x")
+	_ = config.Config{}
+}