Mulitple Gitea Doctor improvements (#10943)

* Add `gitea doctor --list` flag to list the checks that will be run, including those by default
* Add `gitea doctor --run` to run specific checks
* Add `gitea doctor --all` to run all checks
* Add db version checker
* Add non-default recalculate merge bases check/fixer to doctor
* Add hook checker (Fix #9878) and ensure hooks are executable (Fix #6319)
* Fix authorized_keys checker - slight change of functionality here because parsing the command is fragile and we should just check if the authorized_keys file is essentially the same as what gitea would produce. (This is still not perfect as order matters - we should probably just md5sum the two files.)
* Add SCRIPT_TYPE check (Fix #10977)
* Add `gitea doctor --fix` to attempt to fix what is possible to easily fix
* Add `gitea doctor --log-file` to set the log-file, be it a file, stdout or to switch off completely. (Fixes previously undetected bug with certain xorm logging configurations - see @6543 comment.)

Signed-off-by: Andrew Thornton <art27@cantab.net>

models/migrations/migrations.go

@@ -206,6 +206,52 @@ var migrations = []Migration{
 	NewMigration("Add OrgID column to Labels table", addOrgIDLabelColumn),
 }
 
+// GetCurrentDBVersion returns the current db version
+func GetCurrentDBVersion(x *xorm.Engine) (int64, error) {
+	if err := x.Sync(new(Version)); err != nil {
+		return -1, fmt.Errorf("sync: %v", err)
+	}
+
+	currentVersion := &Version{ID: 1}
+	has, err := x.Get(currentVersion)
+	if err != nil {
+		return -1, fmt.Errorf("get: %v", err)
+	}
+	if !has {
+		return -1, nil
+	}
+	return currentVersion.Version, nil
+}
+
+// ExpectedVersion returns the expected db version
+func ExpectedVersion() int64 {
+	return int64(minDBVersion + len(migrations))
+}
+
+// EnsureUpToDate will check if the db is at the correct version
+func EnsureUpToDate(x *xorm.Engine) error {
+	currentDB, err := GetCurrentDBVersion(x)
+	if err != nil {
+		return err
+	}
+
+	if currentDB < 0 {
+		return fmt.Errorf("Database has not been initialised")
+	}
+
+	if minDBVersion > currentDB {
+		return fmt.Errorf("DB version %d (<= %d) is too old for auto-migration. Upgrade to Gitea 1.6.4 first then upgrade to this version", currentDB, minDBVersion)
+	}
+
+	expected := ExpectedVersion()
+
+	if currentDB != expected {
+		return fmt.Errorf(`Current database version %d is not equal to the expected version %d. Please run "gitea [--config /path/to/app.ini] migrate" to update the database version`, currentDB, expected)
+	}
+
+	return nil
+}
+
 // Migrate database to current version
 func Migrate(x *xorm.Engine) error {
 	if err := x.Sync(new(Version)); err != nil {