feat: Add support for renaming workspaces (#3409)

* feat: Implement workspace renaming

* feat: Add hidden rename command (and data loss warning)

* feat: Implement database.IsUniqueViolation

coderd/database/errors.go

@@ -0,0 +1,38 @@
+package database
+
+import (
+	"errors"
+
+	"github.com/lib/pq"
+)
+
+// UniqueConstraint represents a named unique constraint on a table.
+type UniqueConstraint string
+
+// UniqueConstraint enums.
+// TODO(mafredri): Generate these from the database schema.
+const (
+	UniqueWorkspacesOwnerIDLowerIdx UniqueConstraint = "workspaces_owner_id_lower_idx"
+)
+
+// IsUniqueViolation checks if the error is due to a unique violation.
+// If one or more specific unique constraints are given as arguments,
+// the error must be caused by one of them. If no constraints are given,
+// this function returns true for any unique violation.
+func IsUniqueViolation(err error, uniqueConstraints ...UniqueConstraint) bool {
+	var pqErr *pq.Error
+	if errors.As(err, &pqErr) {
+		if pqErr.Code.Name() == "unique_violation" {
+			if len(uniqueConstraints) == 0 {
+				return true
+			}
+			for _, uc := range uniqueConstraints {
+				if pqErr.Constraint == string(uc) {
+					return true
+				}
+			}
+		}
+	}
+
+	return false
+}