DatabaseCursor has a primary associated type

groue · Aug 25, 2024 · be57748 · be57748
1 parent 490b4e5
commit be57748
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Showing 2 changed files with 10 additions and 1 deletion.
diff --git a/GRDB/Core/Statement.swift b/GRDB/Core/Statement.swift
@@ -719,7 +719,7 @@ extension Statement {
 /// [`sqlite3_reset`](https://www.sqlite.org/c3ref/reset.html) when the cursor
 /// is created, and when it is deallocated. Don't share the same prepared
 /// statement between two cursors!
-public protocol DatabaseCursor: Cursor {
+public protocol DatabaseCursor<Element>: Cursor {
     /// Must be initialized to false.
     var _isDone: Bool { get set }
 

diff --git a/Tests/GRDBTests/DatabaseCursorTests.swift b/Tests/GRDBTests/DatabaseCursorTests.swift
@@ -213,6 +213,15 @@ class DatabaseCursorTests: GRDBTestCase {
 //        }
     }
 
+    // This test passes if it compiles
+    func testAssociatedType() throws {
+        func accept(_ cursor: some DatabaseCursor<String>) { }
+        func useCursor(_ db: Database) throws {
+            let cursor = try String.fetchCursor(db, sql: "SELECT 'foo'")
+            accept(cursor)
+        }
+    }
+
     // For profiling tests
     let profilingSQL = """
         WITH RECURSIVE