checkers: add codegenComment checker (go-critic#783)

Checks whether a file has malformed "auto generated" comment.

Signed-off-by: Iskander Sharipov <[email protected]>

checkers/codegenComment_checker.go

@@ -0,0 +1,61 @@
+package checkers
+
+import (
+	"go/ast"
+	"regexp"
+	"strings"
+
+	"github.com/go-lintpack/lintpack"
+	"github.com/go-lintpack/lintpack/astwalk"
+)
+
+func init() {
+	var info lintpack.CheckerInfo
+	info.Name = "codegenComment"
+	info.Tags = []string{"diagnostic", "experimental"}
+	info.Summary = "Detects malformed 'code generated' file comments"
+	info.Before = `// This file was automatically generated by foogen`
+	info.After = `// Code generated by foogen. DO NOT EDIT.`
+
+	collection.AddChecker(&info, func(ctx *lintpack.CheckerContext) lintpack.FileWalker {
+		patterns := []string{
+			"this (?:file|code) (?:was|is) auto(?:matically)? generated",
+			"this (?:file|code) (?:was|is) generated automatically",
+			"this (?:file|code) (?:was|is) generated by",
+			"this (?:file|code) (?:was|is) (?:auto(?:matically)? )?generated",
+			"this (?:file|code) (?:was|is) generated",
+			"code in this file (?:was|is) auto(?:matically)? generated",
+			"generated (?:file|code) - do not edit",
+			// TODO(Quasilyte): more of these.
+		}
+		re := regexp.MustCompile("(?i)" + strings.Join(patterns, "|"))
+		return &codegenCommentChecker{
+			ctx:          ctx,
+			badCommentRE: re,
+		}
+	})
+}
+
+type codegenCommentChecker struct {
+	astwalk.WalkHandler
+	ctx *lintpack.CheckerContext
+
+	badCommentRE *regexp.Regexp
+}
+
+func (c *codegenCommentChecker) WalkFile(f *ast.File) {
+	if f.Doc == nil {
+		return
+	}
+
+	for _, comment := range f.Doc.List {
+		if c.badCommentRE.MatchString(comment.Text) {
+			c.warn(comment)
+			return
+		}
+	}
+}
+
+func (c *codegenCommentChecker) warn(cause ast.Node) {
+	c.ctx.Warn(cause, "comment should match `Code generated .* DO NOT EDIT.` regexp")
+}

checkers/testdata/_integration/check_comments/autogen1.go

@@ -0,0 +1,2 @@
+// THIS FILE WAS GENERATED BY QUASILYTE!
+package foo

checkers/testdata/_integration/check_comments/autogen2.go

@@ -0,0 +1,2 @@
+// This file is auto generated.
+package foo

checkers/testdata/_integration/check_comments/autogen3.go

@@ -0,0 +1,2 @@
+// This file is automatically generated.
+package foo

checkers/testdata/_integration/check_comments/linttest.golden

@@ -1,4 +1,8 @@
 exit status 1
+./autogen1.go:1:1: codegenComment: comment should match `Code generated .* DO NOT EDIT.` regexp
+./autogen2.go:1:1: codegenComment: comment should match `Code generated .* DO NOT EDIT.` regexp
+./autogen3.go:1:1: codegenComment: comment should match `Code generated .* DO NOT EDIT.` regexp
+./autogen4.go:1:1: codegenComment: comment should match `Code generated .* DO NOT EDIT.` regexp
 ./foo.go:5:2: commentedOutImport: remove commented-out "os" import
 ./foo.go:6:2: commentedOutImport: remove commented-out "fmt" import
 ./foo.go:6:2: commentedOutImport: remove commented-out "strconv" import

checkers/testdata/_integration/check_comments/linttest.params

@@ -1 +1 @@
-check -enable=commentedOutImport ./... | linttest.golden
+check -enable=commentedOutImport,codegenComment ./... | linttest.golden

checkers/testdata/codegenComment/positive_tests.go

@@ -0,0 +1,3 @@
+/*! comment should match `Code generated .* DO NOT EDIT.` regexp */
+// This file was automatically generated by Quasilyte.
+package checker_test