chore(lint): forbid usage of regexp.Match(String)? (#2066)

Just to avoid [this
comment](#875 (comment))
again :)

.github/golangci.yml

@@ -38,6 +38,7 @@ linters:
     - gofumpt # Stricter gofmt
     - unused # Checks Go code for unused constants, variables, functions and types
     - gomodguard # Enforces an allow and block list for direct Go module dependencies
+    - forbidigo # Forbids some custom-set identifiers, like regexp.MatchString
 
 linters-settings:
   gofmt:
@@ -60,6 +61,10 @@ linters-settings:
       - opinionated
       - performance
       - style
+  forbidigo:
+    forbid:
+      - p: '^regexp\.(Match|MatchString)$'
+        msg: it will re-compile the regexp for each execution; compile the regexp with regexp.Compile and store it as a singleton
 
 issues:
   whole-files: true

tm2/pkg/amino/genproto/bindings.go

@@ -1100,6 +1100,27 @@ func _fields(args ...interface{}) *ast.FieldList {
 	}
 }
 
+const (
+	reDGTS = `(?:[0-9]+)`
+	reHExX = `(?:0[xX][0-9a-fA-F]+)`
+	rePSCI = `(?:[eE]+?[0-9]+)`
+	reNSCI = `(?:[eE]-[1-9][0-9]+)`
+	reASCI = `(?:[eE][-+]?[0-9]+)`
+)
+
+var (
+	reIsInt = regexp.MustCompile(
+		`^-?(?:` +
+			reDGTS + `|` +
+			reHExX + `)` + rePSCI + `?$`,
+	)
+	reIsFloat = regexp.MustCompile(
+		`^-?(?:` +
+			reDGTS + `\.` + reDGTS + reASCI + `?|` +
+			reDGTS + reNSCI + `)$`,
+	)
+)
+
 // Parses simple expressions (but not all).
 // Useful for parsing strings to ast nodes, like foo.bar["qwe"](),
 // new(bytes.Buffer), *bytes.Buffer, package.MyStruct{FieldA:1}, numeric
@@ -1282,38 +1303,15 @@ func _x(expr string, args ...interface{}) ast.Expr {
 		}
 	}
 	// Numeric int?  We do these before dots, because dots are legal in numbers.
-	const (
-		DGTS = `(?:[0-9]+)`
-		HExX = `(?:0[xX][0-9a-fA-F]+)`
-		PSCI = `(?:[eE]+?[0-9]+)`
-		NSCI = `(?:[eE]-[1-9][0-9]+)`
-		ASCI = `(?:[eE][-+]?[0-9]+)`
-	)
-	isInt, err := regexp.Match(
-		`^-?(?:`+
-			DGTS+`|`+
-			HExX+`)`+PSCI+`?$`,
-		[]byte(expr),
-	)
-	if err != nil {
-		panic("should not happen")
-	}
+	isInt := reIsInt.MatchString(expr)
 	if isInt {
 		return &ast.BasicLit{
 			Kind:  token.INT,
 			Value: expr,
 		}
 	}
 	// Numeric float?  We do these before dots, because dots are legal in floats.
-	isFloat, err := regexp.Match(
-		`^-?(?:`+
-			DGTS+`\.`+DGTS+ASCI+`?|`+
-			DGTS+NSCI+`)$`,
-		[]byte(expr),
-	)
-	if err != nil {
-		panic("should not happen")
-	}
+	isFloat := reIsFloat.MatchString(expr)
 	if isFloat {
 		return &ast.BasicLit{
 			Kind:  token.FLOAT,