Add RevertInconsistentOptions.ignoreUnknownMigrations

Author: adam-fowler

Sources/PostgresMigrations/Migrations.swift

@@ -269,8 +269,10 @@ public actor DatabaseMigrations {
 
         public init(rawValue: Int) { self.rawValue = rawValue }
 
+        // Ignore migrations we don't know about
+        static var ignoreUnknownMigrations: Self { .init(rawValue: 1 << 0) }
         // Remove database entry for migrations we don't know about
-        static var removeUnknownMigrations: Self { .init(rawValue: 1 << 0) }
+        static var removeUnknownMigrations: Self { .init(rawValue: 1 << 1) }
     }
 
     /// Revert database migrations that are inconsistent with the migration list
@@ -319,7 +321,10 @@ public actor DatabaseMigrations {
             // for each group revert migrations
             for group in groups {
                 let groupMigrations = migrations.filter { $0.group == group }
-                let appliedGroupMigrations = appliedMigrations.filter { $0.group == group }
+                var appliedGroupMigrations = appliedMigrations.filter { $0.group == group }
+                if options.contains(.ignoreUnknownMigrations) {
+                    appliedGroupMigrations = appliedGroupMigrations.filter { registeredMigrations[$0.name] != nil }
+                }
 
                 let minMigrationCount = min(groupMigrations.count, appliedGroupMigrations.count)
                 var i = 0

Tests/PostgresMigrationsTests/MigrationTests.swift

@@ -339,16 +339,31 @@ final class MigrationTests: XCTestCase {
                 XCTFail()
             } catch let error as DatabaseMigrationError where error == .cannotRevertMigration {
             }
+            // Run revert ignoring unknown migrations
+            try await migrations.revertInconsistent(
+                client: client,
+                groups: [.default],
+                options: .ignoreUnknownMigrations,
+                logger: Self.logger,
+                dryRun: false
+            )
+            var appliedMigrations = try await getAll(client: client)
+            XCTAssertEqual(appliedMigrations.count, 3)
+            XCTAssertEqual(appliedMigrations[0], "test1")
+            XCTAssertEqual(appliedMigrations[1], "test2")
+            XCTAssertEqual(appliedMigrations[2], "test3")
+
+            // Run revert removing unknown migrations
             try await migrations.revertInconsistent(
                 client: client,
                 groups: [.default],
                 options: .removeUnknownMigrations,
                 logger: Self.logger,
                 dryRun: false
             )
-            let migrations = try await getAll(client: client)
-            XCTAssertEqual(migrations.count, 1)
-            XCTAssertEqual(migrations[0], "test1")
+            appliedMigrations = try await getAll(client: client)
+            XCTAssertEqual(appliedMigrations.count, 1)
+            XCTAssertEqual(appliedMigrations[0], "test1")
         }
     }