Support unprotected file patterns (#16395)

Fixes #16381

Note that changes to unprotected files via the web editor still cannot be pushed directly to the protected branch. I could easily add such support for edits and deletes if needed. But for adding, uploading or renaming unprotected files, it is not trivial.

* Extract & Move GetAffectedFiles to modules/git

models/migrations/migrations.go

@@ -340,6 +340,8 @@ var migrations = []Migration{
 	NewMigration("RecreateIssueResourceIndexTable to have a primary key instead of an unique index", recreateIssueResourceIndexTable),
 	// v193 -> v194
 	NewMigration("Add repo id column for attachment table", addRepoIDForAttachment),
+	// v194 -> v195
+	NewMigration("Add Branch Protection Unprotected Files Column", addBranchProtectionUnprotectedFilesColumn),
 }
 
 // GetCurrentDBVersion returns the current db version

models/migrations/v194.go

@@ -0,0 +1,22 @@
+// 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 migrations
+
+import (
+	"fmt"
+
+	"xorm.io/xorm"
+)
+
+func addBranchProtectionUnprotectedFilesColumn(x *xorm.Engine) error {
+	type ProtectedBranch struct {
+		UnprotectedFilePatterns string `xorm:"TEXT"`
+	}
+
+	if err := x.Sync2(new(ProtectedBranch)); err != nil {
+		return fmt.Errorf("Sync2: %v", err)
+	}
+	return nil
+}