[Internal] Query: Fixes escaped string parsing in SqlParser (#4054)

* Initial commit

* Addressed comments.

Microsoft.Azure.Cosmos/src/Query/Core/Parser/CstToAstVisitor.cs

@@ -9,6 +9,7 @@ namespace Microsoft.Azure.Cosmos.Query.Core.Parser
     using System.Collections.Immutable;
     using System.Diagnostics.Contracts;
     using System.Globalization;
+    using System.Text;
     using Antlr4.Runtime.Misc;
     using Antlr4.Runtime.Tree;
     using Microsoft.Azure.Cosmos.SqlObjects;
@@ -950,8 +951,45 @@ namespace Microsoft.Azure.Cosmos.Query.Core.Parser
         private static string GetStringValueFromNode(IParseTree parseTree)
         {
             string text = parseTree.GetText();
-            string textWithoutQuotes = text.Substring(1, text.Length - 2).Replace("\\\"", "\"");
-            return textWithoutQuotes;
+
+            // 1. Remove leading and trailing (single or double) quotes.
+            // 2. Unescape following characters:
+            //    \" => "
+            //    \\ => \
+            //    \/ => /
+            // Based on the documentation, we should also escape single quote \'.
+            // https://learn.microsoft.com/en-us/azure/cosmos-db/nosql/query/constants#remarks
+            // However that's failing in the parser (before reaching this point) and will be fixed separately (after checking server's behavior).
+            StringBuilder stringBuilder = new StringBuilder(text.Length);
+            for (int index = 1; index < text.Length - 1; index++)
+            {
+                switch (text[index])
+                {
+                    case '\\':
+                        if ((index + 1) < (text.Length - 1))
+                        {
+                            switch (text[index + 1])
+                            {
+                                case '"':
+                                case '\\':
+                                case '/':
+                                    stringBuilder.Append(text[index + 1]);
+                                    index++;
+                                    break;
+                                default:
+                                    stringBuilder.Append(text[index]);
+                                    break;
+                            }
+                        }
+                        break;
+
+                    default:
+                        stringBuilder.Append(text[index]);
+                        break;
+                }
+            }
+
+            return stringBuilder.ToString();
         }
 
         private static Number64 GetNumber64ValueFromNode(IParseTree parseTree)

Microsoft.Azure.Cosmos/tests/Microsoft.Azure.Cosmos.Tests/BaselineTest/BaselineTests.cs

@@ -135,8 +135,8 @@ namespace Microsoft.Azure.Cosmos.Test.BaselineTest
 
             Assert.IsTrue(
                 matched,
-                $@" Baseline File {baselinePath},
-                    Output File {outputPath},
+                $@" Baseline File {Path.GetFullPath(baselinePath)},
+                    Output File {Path.GetFullPath(outputPath)},
                     Expected: {baselineTextSuffix},
                     Actual:   {outputTextSuffix}");
         }

Microsoft.Azure.Cosmos/tests/Microsoft.Azure.Cosmos.Tests/BaselineTest/TestBaseline/ScalarExpressionSqlParserBaselineTests.StringLiteral.xml

@@ -0,0 +1,38 @@
+<Results>
+  <Result>
+    <Input>
+      <Description><![CDATA[Single quoted string literals with escape seqence]]></Description>
+      <Query><![CDATA[SELECT VALUE ['\"DoubleQuote', '\\ReverseSolidus', '\/solidus', '\bBackspace', '\fSeparatorFeed', '\nLineFeed', '\rCarriageReturn', '\tTab', '\u1234']]]></Query>
+    </Input>
+    <Output>
+      <ParsedQuery><![CDATA[SELECT VALUE ["\"DoubleQuote", "\\ReverseSolidus", "/solidus", "\\bBackspace", "\\fSeparatorFeed", "\\nLineFeed", "\\rCarriageReturn", "\\tTab", "\\u1234"]]]></ParsedQuery>
+    </Output>
+  </Result>
+  <Result>
+    <Input>
+      <Description><![CDATA[Double quoted string literals with escape seqence]]></Description>
+      <Query><![CDATA[SELECT VALUE ["'SingleQuote", "\"DoubleQuote", "\\ReverseSolidus", "\/solidus", "\bBackspace", "\fSeparatorFeed", "\nLineFeed", "\rCarriageReturn", "\tTab", "\u1234"]]]></Query>
+    </Input>
+    <Output>
+      <ParsedQuery><![CDATA[SELECT VALUE ["'SingleQuote", "\"DoubleQuote", "\\ReverseSolidus", "/solidus", "\\bBackspace", "\\fSeparatorFeed", "\\nLineFeed", "\\rCarriageReturn", "\\tTab", "\\u1234"]]]></ParsedQuery>
+    </Output>
+  </Result>
+  <Result>
+    <Input>
+      <Description><![CDATA[Single quoted string literals special cases]]></Description>
+      <Query><![CDATA[SELECT VALUE ['\"', '\"\"', '\\', '\\\\', '\/', '\/\/', '\b', '\b\b', '\f', '\f\f', '\n', '\n\n', '\r', '\r\r', '\t', '\t\t', '\u1234', '\u1234\u1234']]]></Query>
+    </Input>
+    <Output>
+      <ParsedQuery><![CDATA[SELECT VALUE ["\"", "\"\"", "\\", "\\\\", "/", "//", "\\b", "\\b\\b", "\\f", "\\f\\f", "\\n", "\\n\\n", "\\r", "\\r\\r", "\\t", "\\t\\t", "\\u1234", "\\u1234\\u1234"]]]></ParsedQuery>
+    </Output>
+  </Result>
+  <Result>
+    <Input>
+      <Description><![CDATA[Double quoted string literals special cases]]></Description>
+      <Query><![CDATA[SELECT VALUE ["\"", "\"\"", "\\", "\\\\", "\/", "\/\/", "\b", "\b\b", "\f", "\f\f", "\n", "\n\n", "\r", "\r\r", "\t", "\t\t", "\u1234", "\u1234\u1234"]]]></Query>
+    </Input>
+    <Output>
+      <ParsedQuery><![CDATA[SELECT VALUE ["\"", "\"\"", "\\", "\\\\", "/", "//", "\\b", "\\b\\b", "\\f", "\\f\\f", "\\n", "\\n\\n", "\\r", "\\r\\r", "\\t", "\\t\\t", "\\u1234", "\\u1234\\u1234"]]]></ParsedQuery>
+    </Output>
+  </Result>
+</Results>

Microsoft.Azure.Cosmos/tests/Microsoft.Azure.Cosmos.Tests/Microsoft.Azure.Cosmos.Tests.csproj

@@ -82,6 +82,9 @@
     <None Update="BaselineTest\TestBaseline\GroupByClauseSqlParserBaselineTests.Tests.xml">
       <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
     </None>
+    <None Update="BaselineTest\TestBaseline\ScalarExpressionSqlParserBaselineTests.StringLiteral.xml">
+      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
+    </None>
     <None Update="BaselineTest\TestBaseline\SelectClauseSqlParserBaselineTests.Tests.xml">
       <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
     </None>

Microsoft.Azure.Cosmos/tests/Microsoft.Azure.Cosmos.Tests/Query/Parser/ScalarExpressionSqlParserBaselineTests.cs

@@ -520,6 +520,30 @@
             this.ExecuteTestSuite(inputs);
         }
 
+        [TestMethod]
+        public void StringLiteral()
+        {
+            List<SqlParserBaselineTestInput> inputs = new List<SqlParserBaselineTestInput>()
+            {
+                // Single quoted string literals do not allow ' even when it's escaped.
+                // Parser currently fails with Antlr4.Runtime.NoViableAltException
+                CreateInput(
+                    description: @"Single quoted string literals with escape seqence",
+                    scalarExpression: @"['\""DoubleQuote', '\\ReverseSolidus', '\/solidus', '\bBackspace', '\fSeparatorFeed', '\nLineFeed', '\rCarriageReturn', '\tTab', '\u1234']"),
+                CreateInput(
+                    description: @"Double quoted string literals with escape seqence",
+                    scalarExpression: @"[""'SingleQuote"", ""\""DoubleQuote"", ""\\ReverseSolidus"", ""\/solidus"", ""\bBackspace"", ""\fSeparatorFeed"", ""\nLineFeed"", ""\rCarriageReturn"", ""\tTab"", ""\u1234""]"),
+                CreateInput(
+                    description: @"Single quoted string literals special cases",
+                    scalarExpression: @"['\""', '\""\""', '\\', '\\\\', '\/', '\/\/', '\b', '\b\b', '\f', '\f\f', '\n', '\n\n', '\r', '\r\r', '\t', '\t\t', '\u1234', '\u1234\u1234']"),
+                CreateInput(
+                    description: @"Double quoted string literals special cases",
+                    scalarExpression: @"[""\"""", ""\""\"""", ""\\"", ""\\\\"", ""\/"", ""\/\/"", ""\b"", ""\b\b"", ""\f"", ""\f\f"", ""\n"", ""\n\n"", ""\r"", ""\r\r"", ""\t"", ""\t\t"", ""\u1234"", ""\u1234\u1234""]"),
+            };
+
+            this.ExecuteTestSuite(inputs);
+        }
+
         public static SqlParserBaselineTestInput CreateInput(string description, string scalarExpression)
         {
             return new SqlParserBaselineTestInput(description, $"SELECT VALUE {scalarExpression}");