From 67a2ed17cafa3f0808e96813ac72f5eb7651328c Mon Sep 17 00:00:00 2001
From: Sanne Grinovero <sanne@hibernate.org>
Date: Tue, 27 Oct 2020 22:03:39 +0000
Subject: [PATCH] HHH-14292 Avoid defensive copy for keywords set in
 NormalizingIdentifierHelperImpl

---
 .../internal/NormalizingIdentifierHelperImpl.java   | 13 +++++++------
 .../jdbc/env/spi/IdentifierHelperBuilder.java       |  6 ++++--
 2 files changed, 11 insertions(+), 8 deletions(-)

diff --git a/hibernate-core/src/main/java/org/hibernate/engine/jdbc/env/internal/NormalizingIdentifierHelperImpl.java b/hibernate-core/src/main/java/org/hibernate/engine/jdbc/env/internal/NormalizingIdentifierHelperImpl.java
index 46ba1c39ef..e7f8072f5b 100644
--- a/hibernate-core/src/main/java/org/hibernate/engine/jdbc/env/internal/NormalizingIdentifierHelperImpl.java
+++ b/hibernate-core/src/main/java/org/hibernate/engine/jdbc/env/internal/NormalizingIdentifierHelperImpl.java
@@ -7,9 +7,9 @@
 package org.hibernate.engine.jdbc.env.internal;
 
 import java.util.Locale;
-import java.util.Set;
 import java.util.TreeSet;
 
+import org.hibernate.AssertionFailure;
 import org.hibernate.boot.model.naming.DatabaseIdentifier;
 import org.hibernate.boot.model.naming.Identifier;
 import org.hibernate.engine.jdbc.env.spi.IdentifierCaseStrategy;
@@ -31,7 +31,7 @@ public class NormalizingIdentifierHelperImpl implements IdentifierHelper {
 	private final boolean globallyQuoteIdentifiers;
 	private final boolean globallyQuoteIdentifiersSkipColumnDefinitions;
 	private final boolean autoQuoteKeywords;
-	private final Set<String> reservedWords = new TreeSet<String>( String.CASE_INSENSITIVE_ORDER );
+	private final TreeSet<String> reservedWords;
 	private final IdentifierCaseStrategy unquotedCaseStrategy;
 	private final IdentifierCaseStrategy quotedCaseStrategy;
 
@@ -41,7 +41,7 @@ public class NormalizingIdentifierHelperImpl implements IdentifierHelper {
 			boolean globallyQuoteIdentifiers,
 			boolean globallyQuoteIdentifiersSkipColumnDefinitions,
 			boolean autoQuoteKeywords,
-			Set<String> reservedWords,
+			TreeSet<String> reservedWords, //careful, we intentionally omit making a defensive copy to not waste memory
 			IdentifierCaseStrategy unquotedCaseStrategy,
 			IdentifierCaseStrategy quotedCaseStrategy) {
 		this.jdbcEnvironment = jdbcEnvironment;
@@ -49,9 +49,7 @@ public class NormalizingIdentifierHelperImpl implements IdentifierHelper {
 		this.globallyQuoteIdentifiers = globallyQuoteIdentifiers;
 		this.globallyQuoteIdentifiersSkipColumnDefinitions = globallyQuoteIdentifiersSkipColumnDefinitions;
 		this.autoQuoteKeywords = autoQuoteKeywords;
-		if ( reservedWords != null ) {
-			this.reservedWords.addAll( reservedWords );
-		}
+		this.reservedWords = reservedWords;
 		this.unquotedCaseStrategy = unquotedCaseStrategy == null ? IdentifierCaseStrategy.UPPER : unquotedCaseStrategy;
 		this.quotedCaseStrategy = quotedCaseStrategy == null ? IdentifierCaseStrategy.MIXED : quotedCaseStrategy;
 	}
@@ -98,6 +96,9 @@ public class NormalizingIdentifierHelperImpl implements IdentifierHelper {
 
 	@Override
 	public boolean isReservedWord(String word) {
+		if ( autoQuoteKeywords == false ) {
+			throw new AssertionFailure( "The reserved keywords map is only initialized if autoQuoteKeywords is true" );
+		}
 		return reservedWords.contains( word );
 	}
 
diff --git a/hibernate-core/src/main/java/org/hibernate/engine/jdbc/env/spi/IdentifierHelperBuilder.java b/hibernate-core/src/main/java/org/hibernate/engine/jdbc/env/spi/IdentifierHelperBuilder.java
index ff1a6f739d..0f74afd8f3 100644
--- a/hibernate-core/src/main/java/org/hibernate/engine/jdbc/env/spi/IdentifierHelperBuilder.java
+++ b/hibernate-core/src/main/java/org/hibernate/engine/jdbc/env/spi/IdentifierHelperBuilder.java
@@ -8,7 +8,6 @@ package org.hibernate.engine.jdbc.env.spi;
 
 import java.sql.DatabaseMetaData;
 import java.sql.SQLException;
-import java.util.Collections;
 import java.util.List;
 import java.util.Set;
 import java.util.TreeSet;
@@ -32,7 +31,10 @@ public class IdentifierHelperBuilder {
 
 	private NameQualifierSupport nameQualifierSupport = NameQualifierSupport.BOTH;
 
-	private Set<String> reservedWords = new TreeSet<String>( String.CASE_INSENSITIVE_ORDER );
+	//TODO interesting computer science puzzle: find a more compact representation?
+	// we only need "contains" on this set, and it has to be case sensitive and efficient.
+	private final TreeSet<String> reservedWords = new TreeSet<>( String.CASE_INSENSITIVE_ORDER );
+
 	private boolean globallyQuoteIdentifiers = false;
 	private boolean skipGlobalQuotingForColumnDefinitions = false;
 	private boolean autoQuoteKeywords = true;