checkers: optimize deprecatedComment (#1188)

Deleted regexp usage. 

Fixes #1184

checkers/deprecatedComment_checker.go

@@ -2,7 +2,6 @@ package checkers
 
 import (
 	"go/ast"
-	"regexp"
 	"strings"
 
 	"github.com/go-critic/go-critic/checkers/internal/astwalk"
@@ -24,12 +23,15 @@ func FuncOld() int`
 	collection.AddChecker(&info, func(ctx *linter.CheckerContext) (linter.FileWalker, error) {
 		c := &deprecatedCommentChecker{ctx: ctx}
 
-		c.commonPatterns = []*regexp.Regexp{
-			regexp.MustCompile(`(?i)this (?:function|type) is deprecated`),
-			regexp.MustCompile(`(?i)deprecated[.!]? use \S* instead`),
-			regexp.MustCompile(`(?i)\[\[deprecated\]\].*`),
-			regexp.MustCompile(`(?i)note: deprecated\b.*`),
-			regexp.MustCompile(`(?i)deprecated in.*`),
+		c.commonPatterns = []string{
+			"this type is deprecated",
+			"this function is deprecated",
+			"[[deprecated]]",
+			"note: deprecated",
+			"deprecated in",
+			"deprecated. use",
+			"deprecated! use",
+			"deprecated use",
 			// TODO(quasilyte): more of these?
 		}
 
@@ -41,6 +43,7 @@ func FuncOld() int`
 			"Dprecated: ",
 			"Derecated: ",
 			"Depecated: ",
+			"Depekated: ",
 			"Deprcated: ",
 			"Depreated: ",
 			"Deprected: ",
@@ -63,7 +66,7 @@ type deprecatedCommentChecker struct {
 	astwalk.WalkHandler
 	ctx *linter.CheckerContext
 
-	commonPatterns []*regexp.Regexp
+	commonPatterns []string
 	commonTypos    []string
 }
 
@@ -114,7 +117,11 @@ func (c *deprecatedCommentChecker) VisitDocComment(doc *ast.CommentGroup) {
 
 		// Check for other commonly used patterns.
 		for _, pat := range c.commonPatterns {
-			if pat.MatchString(l) {
+			if len(l) < len(pat) {
+				continue
+			}
+
+			if strings.EqualFold(l[:len(pat)], pat) {
 				c.warnPattern(comment)
 				return
 			}

checkers/testdata/deprecatedComment/negative_tests.go

@@ -6,6 +6,9 @@ func ProperDeprecationComment() {}
 // This is not a Deprecated: comment at all.
 func FalsePositive1() {}
 
+// This is not a Deprecated?
+func FalsePositive2() {}
+
 // Deprecated is a function name.
 func Deprecated() {}
 
@@ -17,3 +20,14 @@ type Derpecated struct{}
 
 // Note that this one is not deprecated.
 func f() {}
+
+var (
+	// Dep: ...
+	_ = 0
+
+	// deprec
+	_ = 0
+
+	// dePreca
+	_ = 0
+)

checkers/testdata/deprecatedComment/positive_tests.go

@@ -62,6 +62,16 @@ const BadFormat8 = 10
 // [[deprecated]]
 const BadFormat9 = 10
 
+// BadFormat10 is an example, too.
+//
+/*! the proper format is `Deprecated: <text>` */
+// ThIs TyPe iS DepRecateD, use foo instead.
+type BadFormat10 int
+
+/*! use `Deprecated: ` (note the casing) instead of `DEPRECATED: ` */
+// DEPRECATED: part of the old API; use API v2
+func BadFormat11() {}
+
 type badNestedDoc struct {
 	/*! use `Deprecated: ` (note the casing) instead of `deprecated: ` */
 	// deprecated: ha-ha
@@ -121,6 +131,26 @@ var (
 	// Deprecate: ...
 	_ = 0
 
+	/*! typo in `DeprEcate`; should be `Deprecated` */
+	// DeprEcate: ...
+	_ = 0
+
+	/*! typo in `deprecate`; should be `Deprecated` */
+	// deprecate: ...
+	_ = 0
+
+	/*! typo in `dePrecate`; should be `Deprecated` */
+	// dePrecate: ...
+	_ = 0
+
+	/*! typo in `Depekated`; should be `Deprecated` */
+	// Depekated: ...
+	_ = 0
+
+	/*! typo in `DepeKated`; should be `Deprecated` */
+	// DepeKated: ...
+	_ = 0
+
 	/*! typo in `Derpecate`; should be `Deprecated` */
 	// Derpecate: ...
 	_ = 0
@@ -147,3 +177,7 @@ func foo2() {
 /*! the proper format is `Deprecated: <text>` */
 // deprecated in 1.8: use bar instead.
 type foo3 string
+
+/*! the proper format is `Deprecated: <text>` */
+// deprecated in 1.11: use f instead.
+type foo4 string