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fix: PG parser fails on LIKE ? ESCAPE '\\' generated by JPA #6627

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fix: PG parser fails on LIKE ? ESCAPE '\\' generated by JPA #6627

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97 changes: 6 additions & 91 deletions core/src/main/java/com/alibaba/druid/sql/dialect/postgresql/parser/PGLexer.java
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Original file line number Diff line number Diff line change
Expand Up @@ -25,7 +25,6 @@
import static com.alibaba.druid.sql.parser.CharTypes.isIdentifierChar;
import static com.alibaba.druid.sql.parser.DialectFeature.LexerFeature.*;
import static com.alibaba.druid.sql.parser.DialectFeature.ParserFeature.*;
import static com.alibaba.druid.sql.parser.Token.LITERAL_CHARS;

public class PGLexer extends Lexer {
public static final Keywords PG_KEYWORDS;
Expand Down Expand Up @@ -100,96 +99,12 @@ public PGLexer(String input, SQLParserFeature... features) {
}
}

protected void scanString() {
mark = pos;
boolean hasSpecial = false;

for (; ; ) {
if (isEOF()) {
lexError("unclosed.str.lit");
return;
}

ch = charAt(++pos);

if (ch == '\\') {
scanChar();
if (!hasSpecial) {
initBuff(bufPos);
arraycopy(mark + 1, buf, 0, bufPos);
hasSpecial = true;
}

putChar('\\');
switch (ch) {
case '\0':
putChar('\0');
break;
case '\'':
putChar('\'');
break;
case '"':
putChar('"');
break;
case 'b':
putChar('b');
break;
case 'n':
putChar('n');
break;
case 'r':
putChar('r');
break;
case 't':
putChar('t');
break;
case '\\':
putChar('\\');
break;
case 'Z':
putChar((char) 0x1A); // ctrl + Z
break;
default:
putChar(ch);
break;
}
scanChar();
}

if (ch == '\'') {
scanChar();
if (ch != '\'') {
token = LITERAL_CHARS;
break;
} else {
if (!hasSpecial) {
initBuff(bufPos);
arraycopy(mark + 1, buf, 0, bufPos);
hasSpecial = true;
}
putChar('\'');
continue;
}
}

if (!hasSpecial) {
bufPos++;
continue;
}

if (bufPos == buf.length) {
putChar(ch);
} else {
buf[bufPos++] = ch;
}
}

if (!hasSpecial) {
stringVal = subString(mark + 1, bufPos);
} else {
stringVal = new String(buf, 0, bufPos);
}
}
// scanString() is intentionally NOT overridden here.
// The base Lexer.scanString() treats backslash as a regular character,
// which matches PostgreSQL's standard_conforming_strings = on (default since PG 9.1).
// The previous override treated backslash as an escape character inside string literals,
// causing parse failures for SQL like: LIKE ? ESCAPE '\' (generated by JPA/Hibernate).
// See: https://github.com/alibaba/druid/issues/6413

public void scanSharp() {
scanChar();
Expand Down
120 changes: 120 additions & 0 deletions core/src/test/java/com/alibaba/druid/bvt/sql/postgresql/issues/Issue6413.java
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Original file line number Diff line number Diff line change
@@ -0,0 +1,120 @@
package com.alibaba.druid.bvt.sql.postgresql.issues;

import com.alibaba.druid.DbType;
import com.alibaba.druid.sql.ast.SQLStatement;
import com.alibaba.druid.sql.parser.SQLParserUtils;
import com.alibaba.druid.sql.parser.SQLStatementParser;
import org.junit.jupiter.api.Test;

import java.util.List;

import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertNotNull;
import static org.junit.jupiter.api.Assertions.assertTrue;

/**
* Fix PostgreSQL parser failing on LIKE ? ESCAPE '\' syntax generated by JPA/Hibernate.
* <p>
* The PGLexer treated backslash as an escape character inside string literals,
* which is incorrect for standard PostgreSQL (standard_conforming_strings = on since PG 9.1).
* This caused '\' to be parsed as an escaped quote instead of a string containing a backslash.
*
* @see <a href="https://github.com/alibaba/druid/issues/6413">Issue #6413</a>
*/
public class Issue6413 {
@Test
public void test_like_escape_backslash() {
// Exact SQL from the bug report (JPA-generated)
String sql = "select rf1_0.id,rf1_0.name from real_functions rf1_0 "
+ "left join groups g1_0 on g1_0.id=rf1_0.group_id "
+ "where rf1_0.name like ? escape '\\' and g1_0.id=? fetch first ? rows only";

for (DbType dbType : new DbType[]{DbType.postgresql, DbType.greenplum, DbType.edb}) {
SQLStatementParser parser = SQLParserUtils.createSQLStatementParser(sql, dbType);
List<SQLStatement> stmtList = parser.parseStatementList();
assertEquals(1, stmtList.size());
assertNotNull(stmtList.get(0));
}
}

@Test
public void test_like_escape_backslash_simple() {
// Minimal reproduction case
String sql = "select * from t where name like ? escape '\\'";
for (DbType dbType : new DbType[]{DbType.postgresql, DbType.greenplum, DbType.edb}) {
SQLStatementParser parser = SQLParserUtils.createSQLStatementParser(sql, dbType);
List<SQLStatement> stmtList = parser.parseStatementList();
assertEquals(1, stmtList.size());
}
}

@Test
public void test_like_escape_non_backslash_still_works() {
// Other escape characters should still work
for (String escapeChar : new String[]{"#", "!", "~"}) {
String sql = "select * from t where name like ? escape '" + escapeChar + "'";
SQLStatementParser parser = SQLParserUtils.createSQLStatementParser(sql, DbType.postgresql);
List<SQLStatement> stmtList = parser.parseStatementList();
assertEquals(1, stmtList.size());
}
}

@Test
public void test_string_with_backslash_in_pg() {
// Standard PG strings with backslash should parse correctly
String sql = "select * from t where name = '\\'";
SQLStatementParser parser = SQLParserUtils.createSQLStatementParser(sql, DbType.postgresql);
List<SQLStatement> stmtList = parser.parseStatementList();
assertEquals(1, stmtList.size());
}

@Test
public void test_string_with_double_backslash_in_pg() {
// Double backslash in standard PG string
String sql = "select * from t where name = '\\\\'";
SQLStatementParser parser = SQLParserUtils.createSQLStatementParser(sql, DbType.postgresql);
List<SQLStatement> stmtList = parser.parseStatementList();
assertEquals(1, stmtList.size());
}

@Test
public void test_like_escape_backslash_with_wall_filter() {
// Verify it also works through WallProvider (the actual failure path in the bug report)
String sql = "select rf1_0.id from real_functions rf1_0 "
+ "where rf1_0.name like ? escape '\\' and rf1_0.group_id=? fetch first ? rows only";

// Parsing should succeed (WallFilter calls parser internally)
SQLStatementParser parser = SQLParserUtils.createSQLStatementParser(sql, DbType.postgresql);
List<SQLStatement> stmtList = parser.parseStatementList();
assertEquals(1, stmtList.size());
String output = stmtList.get(0).toString();
assertTrue(output.contains("ESCAPE"));
}

@Test
public void test_not_like_escape_backslash() {
// NOT LIKE with backslash ESCAPE should also work
String sql = "select * from t where name not like ? escape '\\'";
SQLStatementParser parser = SQLParserUtils.createSQLStatementParser(sql, DbType.postgresql);
List<SQLStatement> stmtList = parser.parseStatementList();
assertEquals(1, stmtList.size());
}

@Test
public void test_ilike_with_backslash_string() {
// ILIKE (PG-specific) with backslash in string pattern
String sql = "select * from t where name ilike '%test\\%'";
SQLStatementParser parser = SQLParserUtils.createSQLStatementParser(sql, DbType.postgresql);
List<SQLStatement> stmtList = parser.parseStatementList();
assertEquals(1, stmtList.size());
}

@Test
public void test_pg_double_single_quote_still_works() {
// PG standard '' escape for single quotes must still work
String sql = "select * from t where name = 'it''s a test'";
SQLStatementParser parser = SQLParserUtils.createSQLStatementParser(sql, DbType.postgresql);
List<SQLStatement> stmtList = parser.parseStatementList();
assertEquals(1, stmtList.size());
}
}
4 changes: 2 additions & 2 deletions core/src/test/resources/bvt/parser/postgresql/0.txt
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Expand Up @@ -1172,11 +1172,11 @@ FROM (
WHERE 1 = 1
------------------------------------------------------------------------------------------------------------------------
select offerId, offerIds
from cnres.function_select_get_p4p_offer_by_sps('\'1160160508\',\'1085432755\',\'971765217\'')
from cnres.function_select_get_p4p_offer_by_sps('''1160160508'',''1085432755'',''971765217''')
as a( offerId character varying(256), offerIds character varying(4000) )
--------------------
SELECT offerId, offerIds
FROM cnres.function_select_get_p4p_offer_by_sps('\''1160160508\'',\''1085432755\'',\''971765217\''') AS a
FROM cnres.function_select_get_p4p_offer_by_sps('''1160160508'',''1085432755'',''971765217''') AS a
(offerId character varying(256), offerIds character varying(4000))
------------------------------------------------------------------------------------------------------------------------
SELECT TITLE_ID,WEB_ID,MENU_TYPE_ID,MENU_ID,TITLE
Expand Down