fix: backslash is not a valid quote escape (#317)

The SimpleParser would accept backslash+quote as a valid escape mechanism for a quote inside a quoted string. This is not correct for PostgreSQL, and instead should be two equal quotes directly following each other.
GoogleCloudPlatform · Aug 15, 2022 · dc32af4 · dc32af4
1 parent 819a653
commit dc32af4
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Showing 3 changed files with 59 additions and 9 deletions.
diff --git a/src/main/java/com/google/cloud/spanner/pgadapter/statements/SimpleParser.java b/src/main/java/com/google/cloud/spanner/pgadapter/statements/SimpleParser.java
@@ -119,8 +119,12 @@ String parseExpressionUntilKeyword(ImmutableList<String> keywords) {
     int parens = 0;
     while (pos < sql.length()) {
       if (quoted) {
-        if (sql.charAt(pos) == startQuote && sql.charAt(pos - 1) != '\\') {
-          quoted = false;
+        if (sql.charAt(pos) == startQuote) {
+          if (pos == (sql.length() - 1) || sql.charAt(pos + 1) != startQuote) {
+            quoted = false;
+          } else {
+            pos++;
+          }
         }
       } else {
         if (sql.charAt(pos) == '\'' || sql.charAt(pos) == '"') {
@@ -257,19 +261,28 @@ private boolean internalEat(
       boolean skipWhitespaceBefore,
       boolean requireWhitespaceAfter,
       boolean updatePos) {
+    int originalPos = pos;
     if (skipWhitespaceBefore) {
       skipWhitespaces();
     }
     if (pos + keyword.length() > sql.length()) {
+      if (!updatePos) {
+        pos = originalPos;
+      }
       return false;
     }
     if (sql.substring(pos, pos + keyword.length()).equalsIgnoreCase(keyword)
         && (!requireWhitespaceAfter || isValidEndOfKeyword(pos + keyword.length()))) {
       if (updatePos) {
         pos = pos + keyword.length();
+      } else {
+        pos = originalPos;
       }
       return true;
     }
+    if (!updatePos) {
+      pos = originalPos;
+    }
     return false;
   }
 

diff --git a/src/test/java/com/google/cloud/spanner/pgadapter/statements/IntermediateStatementTest.java b/src/test/java/com/google/cloud/spanner/pgadapter/statements/IntermediateStatementTest.java
@@ -244,7 +244,7 @@ public void testTransformUpdateToSelectParams() {
         "select $1, $2, $3 from (select col1=$1, col2=$2 from foo where id=$3) p",
         transformUpdate("update foo set col1=$1, col2=$2  where id=$3").getSql());
     assertEquals(
-        "select $1, $2, $3 from (select col1=col2 + $1 , "
+        "select $1, $2, $3 from (select col1=col2 + $1, "
             + "col2=coalesce($1, $2, $3, to_char(current_timestamp())), "
             + "col3 = 15 "
             + "from foo where id=$3 and value>100) p",

diff --git a/src/test/java/com/google/cloud/spanner/pgadapter/statements/SimpleParserTest.java b/src/test/java/com/google/cloud/spanner/pgadapter/statements/SimpleParserTest.java
@@ -20,6 +20,7 @@
 import static org.junit.Assert.assertTrue;
 
 import com.google.cloud.spanner.pgadapter.statements.SimpleParser.TableOrIndexName;
+import com.google.common.collect.ImmutableList;
 import java.util.Arrays;
 import java.util.Collections;
 import org.junit.Test;
@@ -57,6 +58,7 @@ public void testEatKeyword() {
     assertTrue(new SimpleParser("select\"id\"from\"foo\"").eatKeyword("select"));
     assertTrue(new SimpleParser("select/*comment*/id from foo").eatKeyword("select"));
     assertFalse(new SimpleParser("select$$foo$$").eatKeyword("select"));
+    assertFalse(new SimpleParser("'select").eatKeyword("select"));
   }
 
   @Test
@@ -189,9 +191,9 @@ public void testParseExpression() {
     assertEquals(
         "(foo('bar\", test'))", new SimpleParser("  (foo('bar\", test')),bar").parseExpression());
     assertEquals(
-        "(foo('bar\\', test'))", new SimpleParser("  (foo('bar\\', test')),bar").parseExpression());
+        "(foo('bar'', test'))", new SimpleParser("  (foo('bar'', test')),bar").parseExpression());
     assertEquals("''", new SimpleParser("''").parseExpression());
-    assertEquals("'\\''", new SimpleParser("'\\''").parseExpression());
+    assertEquals("''''", new SimpleParser("''''").parseExpression());
     assertEquals("'\"'", new SimpleParser("'\"'").parseExpression());
 
     assertNull(new SimpleParser("\"foo").parseExpression());
@@ -256,11 +258,10 @@ public void testParseExpressionList() {
         Arrays.asList("(foo('bar\", test'))", "bar"),
         new SimpleParser("  (foo('bar\", test')),bar").parseExpressionList());
     assertEquals(
-        Arrays.asList("(foo('bar\\', test'))", "bar"),
-        new SimpleParser("  (foo('bar\\', test')),bar").parseExpressionList());
+        Arrays.asList("(foo('bar'', test'))", "bar"),
+        new SimpleParser("  (foo('bar'', test')),bar").parseExpressionList());
     assertEquals(Collections.singletonList("''"), new SimpleParser("''").parseExpressionList());
-    assertEquals(
-        Collections.singletonList("'\\''"), new SimpleParser("'\\''").parseExpressionList());
+    assertEquals(Collections.singletonList("''''"), new SimpleParser("''''").parseExpressionList());
     assertEquals(Collections.singletonList("'\"'"), new SimpleParser("'\"'").parseExpressionList());
 
     assertNull(new SimpleParser("\"foo").parseExpressionList());
@@ -271,4 +272,40 @@ public void testParseExpressionList() {
     assertNull(new SimpleParser("foo((bar, test) bar").parseExpressionList());
     assertEquals(Collections.singletonList("foo"), new SimpleParser("foo)(").parseExpressionList());
   }
+
+  @Test
+  public void testParseExpressionUntil() {
+    assertEquals(
+        "insert into foo values ('select')",
+        new SimpleParser("insert into foo values ('select')")
+            .parseExpressionUntilKeyword(ImmutableList.of("select")));
+    assertEquals(
+        "insert into foo",
+        new SimpleParser("insert into foo select * from bar")
+            .parseExpressionUntilKeyword(ImmutableList.of("select")));
+    assertEquals(
+        "insert into foo values ('''select''')",
+        new SimpleParser("insert into foo values ('''select''')")
+            .parseExpressionUntilKeyword(ImmutableList.of("select")));
+    assertEquals(
+        "insert into foo (\"''\")",
+        new SimpleParser("insert into foo (\"''\") select * from bar")
+            .parseExpressionUntilKeyword(ImmutableList.of("select")));
+    assertEquals(
+        "insert into foo values ('''select''')",
+        new SimpleParser("insert into foo values ('''select''') select 1")
+            .parseExpressionUntilKeyword(ImmutableList.of("select")));
+    assertEquals(
+        "select \"insert\" from bar",
+        new SimpleParser("select \"insert\" from bar")
+            .parseExpressionUntilKeyword(ImmutableList.of("insert")));
+    assertEquals(
+        "select \"\"\"insert\"\"\" from bar",
+        new SimpleParser("select \"\"\"insert\"\"\" from bar")
+            .parseExpressionUntilKeyword(ImmutableList.of("insert")));
+    assertEquals(
+        "insert into foo (\"\"\"\")",
+        new SimpleParser("insert into foo (\"\"\"\") select * from bar")
+            .parseExpressionUntilKeyword(ImmutableList.of("select")));
+  }
 }