Better fix for #1357

Previous fix would not correctly address #1357 when invalid double-quoted identifiers are interpreted as string literals (Configuration.acceptsDoubleQuotedStringLiterals = true, or SQLCipher 3)
groue · Apr 1, 2023 · b81e858 · b81e858
1 parent 82f300e
commit b81e858
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Showing 2 changed files with 19 additions and 8 deletions.
diff --git a/GRDB/QueryInterface/SQL/SQLRelation.swift b/GRDB/QueryInterface/SQL/SQLRelation.swift
@@ -612,18 +612,17 @@ extension SQLRelation {
             guard !isDistinct else {
                 return try fetchTrivialCount(db)
             }
-
+
+            // <https://github.com/groue/GRDB.swift/issues/1357>
+            guard selection.allSatisfy(\.isTriviallyCountable) else {
+                return try fetchTrivialCount(db)
+            }
+
             // SELECT expr1, expr2, ... FROM tableName ...
             // ->
             // SELECT COUNT(*) FROM tableName ...
             let countRelation = unordered().select(.countAll)
-            do {
-                return try QueryInterfaceRequest(relation: countRelation).fetchOne(db)!
-            } catch {
-                // <https://github.com/groue/GRDB.swift/issues/1357>
-                // TODO: can we inspect the request and avoid catching an error?
-                return try fetchTrivialCount(db)
-            }
+            return try QueryInterfaceRequest(relation: countRelation).fetchOne(db)!
         }
     }
 

diff --git a/GRDB/QueryInterface/SQL/SQLSelection.swift b/GRDB/QueryInterface/SQL/SQLSelection.swift
@@ -244,6 +244,18 @@ extension SQLSelection {
             return .literal(sqlLiteral.qualified(with: alias))
         }
     }
+
+    /// Supports SQLRelation.fetchCount.
+    ///
+    /// See <https://github.com/groue/GRDB.swift/issues/1357>
+    var isTriviallyCountable: Bool {
+        switch impl {
+        case .aliasedExpression, .literal:
+            return false
+        case .allColumns, .qualifiedAllColumns, .expression:
+            return true
+        }
+    }
 }
 
 extension [SQLSelection] {