Preserve empty SQLite strings

Sources/LSQLite/Database/Database+Filename.swift

@@ -12,9 +12,6 @@ extension Database {
             return nil
         }
         let string = String(cString: cString)
-        guard !string.isEmpty else {
-            return nil
-        }
         return string
     }
 }

Sources/LSQLite/ResultCode.swift

@@ -414,9 +414,6 @@ import MissedSwiftSQLite
             return nil
         }
         let string = String(cString: cString)
-        guard !string.isEmpty else {
-            return nil
-        }
         return string
     }
 

Sources/LSQLite/Statement/Statement+Bind.swift

@@ -137,9 +137,6 @@ extension Statement {
             return nil
         }
         let string = String(cString: cString)
-        guard !string.isEmpty else {
-            return nil
-        }
         return string
     }
 

Sources/LSQLite/Statement/Statement+Column.swift

@@ -21,9 +21,6 @@ extension Statement {
             return nil
         }
         let string = String(cString: cString)
-        guard !string.isEmpty else {
-            return nil
-        }
         return string
     }
 
@@ -40,9 +37,6 @@ extension Statement {
             return nil
         }
         let string = String(cString: cString)
-        guard !string.isEmpty else {
-            return nil
-        }
         return string
     }
 
@@ -59,9 +53,6 @@ extension Statement {
             return nil
         }
         let string = String(cString: cString)
-        guard !string.isEmpty else {
-            return nil
-        }
         return string
     }
 
@@ -78,9 +69,6 @@ extension Statement {
             return nil
         }
         let string = String(cString: cString)
-        guard !string.isEmpty else {
-            return nil
-        }
         return string
     }
 
@@ -96,9 +84,6 @@ extension Statement {
             return nil
         }
         let string = String(cString: cString)
-        guard !string.isEmpty else {
-            return nil
-        }
         return string
     }
 
@@ -163,9 +148,6 @@ extension Statement {
             return nil
         }
         let string = String(cString: cString)
-        guard !string.isEmpty else {
-            return nil
-        }
         return string
     }
 

Sources/LSQLite/Statement/Statement+SQL.swift

@@ -11,9 +11,6 @@ extension Statement {
             return nil
         }
         let string = String(cString: cString)
-        guard !string.isEmpty else {
-            return nil
-        }
         return string
     }
 
@@ -34,9 +31,6 @@ extension Statement {
             return nil
         }
         let string = String(cString: cString)
-        guard !string.isEmpty else {
-            return nil
-        }
         return string
     }
 }

Tests/LSQLiteTests/Database/Database+FilenameTests.swift

@@ -4,12 +4,12 @@ import Testing
 
 @Suite("Database+Filename")
 struct DatabaseFilenameTests {
-    @Test("filename returns nil for in-memory database")
-    func filenameReturnsNilForInMemoryDatabase() throws {
+    @Test("filename returns empty string for in-memory database")
+    func filenameReturnsEmptyStringForInMemoryDatabase() throws {
         var database: Database?
         try #require(Database.open(&database, at: .memory, withOpenFlags: [.readwrite, .create]) == .ok)
         let openDatabase = try #require(database)
-        #expect(openDatabase.filename(forDatabaseNamed: "main") == nil)
+        #expect(openDatabase.filename(forDatabaseNamed: "main") == "")
         #expect(openDatabase.filename(forDatabaseNamed: "missing") == nil)
         _ = openDatabase.close()
     }

Tests/LSQLiteTests/Statement/Statement+ColumnTests.swift

@@ -55,7 +55,7 @@ final class StatementColumnTests {
         #expect(prepared.columnDouble(at: 3) == 3.5)
         #expect(prepared.columnInt(at: 2) == 42)
         #expect(prepared.columnInt64(at: 2) == 42)
-        #expect(prepared.columnText(at: 0) == nil)
+        #expect(prepared.columnText(at: 0) == "")
         #expect(prepared.columnText(at: 4) == "x")
         #expect(prepared.columnText(at: 5) == nil)
         #expect(prepared.columnBytes(at: 1) == 2)
@@ -66,8 +66,8 @@ final class StatementColumnTests {
         #expect(prepared.finalize() == .ok)
     }
 
-    @Test("column metadata treats empty identifiers as nil")
-    func columnMetadataTreatsEmptyIdentifiersAsNil() throws {
+    @Test("column metadata returns empty identifiers")
+    func columnMetadataReturnsEmptyIdentifiers() throws {
         try #require(database.exec("ATTACH DATABASE ':memory:' AS \"\"") == .ok)
         try #require(database.exec("CREATE TABLE \"\".\"\" (\"\" \"\")") == .ok)
         try #require(database.exec("INSERT INTO \"\".\"\" VALUES ('x')") == .ok)
@@ -77,11 +77,11 @@ final class StatementColumnTests {
         let prepared = try #require(statement)
 
         #expect(prepared.step() == .row)
-        #expect(prepared.columnName(at: 0) == nil)
-        #expect(prepared.columnDatabaseName(at: 0) == nil)
-        #expect(prepared.columnTableName(at: 0) == nil)
-        #expect(prepared.columnOriginName(at: 0) == nil)
-        #expect(prepared.columnDeclaredType(at: 0) == nil)
+        #expect(prepared.columnName(at: 0) == "")
+        #expect(prepared.columnDatabaseName(at: 0) == "")
+        #expect(prepared.columnTableName(at: 0) == "")
+        #expect(prepared.columnOriginName(at: 0) == "")
+        #expect(prepared.columnDeclaredType(at: 0) == "")
         #expect(prepared.step() == .done)
         #expect(prepared.finalize() == .ok)
     }