Add tag protection (#15629)

* Added tag protection in hook.

* Prevent UI tag creation if protected.

* Added settings page.

* Added tests.

* Added suggestions.

* Moved tests.

* Use individual errors.

* Removed unneeded methods.

* Switched delete selector.

* Changed method names.

* No reason to be unique.

* Allow editing of protected tags.

* Removed unique key from migration.

* Added docs page.

* Changed date.

* Respond with 404 to not found tags.

* Replaced glob with regex pattern.

* Added support for glob and regex pattern.

* Updated documentation.

* Changed white* to allow*.

* Fixed edit button link.

* Added cancel button.

Co-authored-by: zeripath <art27@cantab.net>
Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>

modules/validation/regex_pattern_test.go

@@ -0,0 +1,60 @@
+// Copyright 2021 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package validation
+
+import (
+	"regexp"
+	"testing"
+
+	"gitea.com/go-chi/binding"
+)
+
+func getRegexPatternErrorString(pattern string) string {
+	if _, err := regexp.Compile(pattern); err != nil {
+		return err.Error()
+	}
+	return ""
+}
+
+var regexValidationTestCases = []validationTestCase{
+	{
+		description: "Empty regex pattern",
+		data: TestForm{
+			RegexPattern: "",
+		},
+		expectedErrors: binding.Errors{},
+	},
+	{
+		description: "Valid regex",
+		data: TestForm{
+			RegexPattern: `(\d{1,3})+`,
+		},
+		expectedErrors: binding.Errors{},
+	},
+
+	{
+		description: "Invalid regex",
+		data: TestForm{
+			RegexPattern: "[a-",
+		},
+		expectedErrors: binding.Errors{
+			binding.Error{
+				FieldNames:     []string{"RegexPattern"},
+				Classification: ErrRegexPattern,
+				Message:        getRegexPatternErrorString("[a-"),
+			},
+		},
+	},
+}
+
+func Test_RegexPatternValidation(t *testing.T) {
+	AddBindingRules()
+
+	for _, testCase := range regexValidationTestCases {
+		t.Run(testCase.description, func(t *testing.T) {
+			performValidationTest(t, testCase)
+		})
+	}
+}