Remove shadow tables from database dump

GRDB/Dump/Database+Dump.swift

@@ -129,6 +129,9 @@ extension Database {
     ///
     /// > Note: Internal SQLite and GRDB schema objects are not recorded
     /// > (those with a name that starts with "sqlite_" or "grdb_").
+    /// >
+    /// > [Shadow tables](https://www.sqlite.org/vtab.html#xshadowname) are
+    /// > not recorded, starting SQLite 3.37+.
     ///
     /// - Parameters:
     ///   - format: The output format.
@@ -252,7 +255,7 @@ extension Database {
             """)
         for row in sqlRows {
             let name: String = row[1]
-            if Database.isSQLiteInternalTable(name) || Database.isGRDBInternalTable(name) {
+            if try ignoresObject(named: name) {
                 continue
             }
             stream.writeln(row[0])
@@ -266,12 +269,42 @@ extension Database {
                 ORDER BY name COLLATE NOCASE
                 """)
             .filter {
-                !(Database.isSQLiteInternalTable($0) || Database.isGRDBInternalTable($0))
+                try !ignoresObject(named: $0)
             }
         if tables.isEmpty { return }
         stream.write("\n")
         try _dumpTables(tables, format: format, tableHeader: .always, stableOrder: true, to: &stream)
     }
+
+    private func ignoresObject(named name: String) throws -> Bool {
+        if Database.isSQLiteInternalTable(name) { return true }
+        if Database.isGRDBInternalTable(name) { return true }
+        if try isShadowTable(name) { return true }
+        return false
+    }
+
+    private func isShadowTable(_ tableName: String) throws -> Bool {
+#if GRDBCUSTOMSQLITE || GRDBCIPHER
+        // Maybe SQLCipher is too old: check actual version
+        if sqlite3_libversion_number() >= 3037000 {
+            guard let table = try table(tableName) else {
+                // Not a table
+                return false
+            }
+            return table.kind == .shadow
+        }
+#else
+        if #available(iOS 15.4, macOS 12.4, tvOS 15.4, watchOS 8.5, *) { // SQLite 3.37+
+            guard let table = try table(tableName) else {
+                // Not a table
+                return false
+            }
+            return table.kind == .shadow
+        }
+#endif
+        // Don't know
+        return false
+    }
 }
 
 /// Options for printing table names.

GRDB/Dump/DatabaseReader+dump.swift

@@ -120,6 +120,9 @@ extension DatabaseReader {
     ///
     /// > Note: Internal SQLite and GRDB schema objects are not recorded
     /// > (those with a name that starts with "sqlite_" or "grdb_").
+    /// >
+    /// > [Shadow tables](https://www.sqlite.org/vtab.html#xshadowname) are
+    /// > not recorded, starting SQLite 3.37+.
     ///
     /// - Parameters:
     ///   - format: The output format.

Tests/GRDBTests/DatabaseDumpTests.swift

@@ -1336,6 +1336,78 @@ final class DatabaseDumpTests: GRDBTestCase {
         }
     }
 
+    func test_dumpContent_ignores_shadow_tables() throws {
+        guard sqlite3_libversion_number() >= 3037000 else {
+            throw XCTSkip("Can't detect shadow tables")
+        }
+
+        try makeDatabaseQueue().write { db in
+            try db.create(table: "document") { t in
+                t.autoIncrementedPrimaryKey("id")
+                t.column("body")
+            }
+
+            try db.execute(sql: "INSERT INTO document VALUES (1, 'Hello world!')")
+
+            try db.create(virtualTable: "document_ft", using: FTS4()) { t in
+                t.synchronize(withTable: "document")
+                t.column("body")
+            }
+
+            let stream = TestStream()
+            try db.dumpContent(to: stream)
+            print(stream.output)
+            XCTAssertEqual(stream.output, """
+                sqlite_master
+                CREATE TABLE "document" ("id" INTEGER PRIMARY KEY AUTOINCREMENT, "body");
+                CREATE TRIGGER "__document_ft_ai" AFTER INSERT ON "document" BEGIN
+                    INSERT INTO "document_ft"("docid", "body") VALUES(new."id", new."body");
+                END;
+                CREATE TRIGGER "__document_ft_au" AFTER UPDATE ON "document" BEGIN
+                    INSERT INTO "document_ft"("docid", "body") VALUES(new."id", new."body");
+                END;
+                CREATE TRIGGER "__document_ft_bd" BEFORE DELETE ON "document" BEGIN
+                    DELETE FROM "document_ft" WHERE docid=old."id";
+                END;
+                CREATE TRIGGER "__document_ft_bu" BEFORE UPDATE ON "document" BEGIN
+                    DELETE FROM "document_ft" WHERE docid=old."id";
+                END;
+                CREATE VIRTUAL TABLE "document_ft" USING fts4(body, content="document");
+
+                document
+                1|Hello world!
+
+                document_ft
+                Hello world!
+
+                """)
+        }
+    }
+
+    func test_dumpContent_ignores_GRDB_internal_tables() throws {
+        let dbQueue = try makeDatabaseQueue()
+        var migrator = DatabaseMigrator()
+        migrator.registerMigration("v1") { db in
+            try db.create(table: "player") { t in
+                t.autoIncrementedPrimaryKey("id")
+            }
+        }
+        try migrator.migrate(dbQueue)
+
+        try dbQueue.read { db in
+            let stream = TestStream()
+            try db.dumpContent(to: stream)
+            print(stream.output)
+            XCTAssertEqual(stream.output, """
+                sqlite_master
+                CREATE TABLE "player" ("id" INTEGER PRIMARY KEY AUTOINCREMENT);
+
+                player
+
+                """)
+        }
+    }
+
     // MARK: - Support Databases
 
     private func makeValuesDatabase() throws -> DatabaseQueue {