fix CborWriter bug when writing tagged empty collections (dotnet#39786)

Jacksondr5 · Aug 10, 2020 · ac4b197 · ac4b197
1 parent b97c509
commit ac4b197
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Showing 3 changed files with 25 additions and 11 deletions.
diff --git a/src/libraries/System.Formats.Cbor/src/Resources/Strings.resx b/src/libraries/System.Formats.Cbor/src/Resources/Strings.resx
@@ -121,7 +121,7 @@
     <value>The destination is too small to hold the encoded value.</value>
   </data>
   <data name="Cbor_PopMajorTypeMismatch" xml:space="preserve">
-    <value>Cannot perform the requested operation, the current context is '{0}'.</value>
+    <value>Cannot perform the requested operation, the current major type context is '{0}'.</value>
   </data>
   <data name="Cbor_NotAtEndOfDefiniteLengthDataItem" xml:space="preserve">
     <value>Not at end of the definite-length data item.</value>
@@ -246,4 +246,4 @@
   <data name="CborContentException_DefaultMessage" xml:space="preserve">
     <value>The CBOR encoding is invalid.</value>
   </data>
-</root>
+</root>
diff --git a/src/libraries/System.Formats.Cbor/src/System/Formats/Cbor/Writer/CborWriter.cs b/src/libraries/System.Formats.Cbor/src/System/Formats/Cbor/Writer/CborWriter.cs
@@ -292,6 +292,7 @@ private void PushDataItem(CborMajorType newMajorType, int? definiteLength)
             _keysRequireSorting = false;
             _keyEncodingRanges = null;
             _keyValuePairEncodingRanges = null;
+            _isTagContext = false;
         }
 
         private void PopDataItem(CborMajorType typeToPop)
@@ -313,7 +314,7 @@ private void PopDataItem(CborMajorType typeToPop)
 
             if (_isTagContext)
             {
-                // writer expecting value after a tag data item , cannot pop the current context
+                // writer expecting value after a tag data item, cannot pop the current context
                 throw new InvalidOperationException(SR.Format(SR.Cbor_PopMajorTypeMismatch, (int)CborMajorType.Tag));
             }
 

diff --git a/src/libraries/System.Formats.Cbor/tests/Writer/CborWriterTests.Map.cs b/src/libraries/System.Formats.Cbor/tests/Writer/CborWriterTests.Map.cs
@@ -101,15 +101,15 @@ public static void WriteMap_IndefiniteLength_WithPatching_NestedValues_HappyPath
         [InlineData(new object[] { Map, "a", "A", -1, 2, new byte[] { }, new byte[] { 1 } }, "a3200240410161616141")]
         [InlineData(new object[] { Map, new object[] { Map, 3, 4, 1, 2 }, 0, new object[] { 1, 2, 3 }, 0, new string[] { "a", "b" }, 0, new string[] { Hex, "ab", "" }, 00 }, "a441ab00626162008301020300a20102030400")]
         public static void WriteMap_IndefiniteLength_WithPatching_Ctap2Sorting_HappyPath(object[] values, string expectedHexEncoding)
-    {
-        byte[] expectedEncoding = expectedHexEncoding.HexToByteArray();
-        var writer = new CborWriter(CborConformanceMode.Ctap2Canonical, convertIndefiniteLengthEncodings: true);
-        Helpers.WriteMap(writer, values, useDefiniteLengthCollections: false);
-        byte[] actualEncoding = writer.Encode();
-        AssertHelper.HexEqual(expectedEncoding, actualEncoding);
-    }
+        {
+            byte[] expectedEncoding = expectedHexEncoding.HexToByteArray();
+            var writer = new CborWriter(CborConformanceMode.Ctap2Canonical, convertIndefiniteLengthEncodings: true);
+            Helpers.WriteMap(writer, values, useDefiniteLengthCollections: false);
+            byte[] actualEncoding = writer.Encode();
+            AssertHelper.HexEqual(expectedEncoding, actualEncoding);
+        }
 
-    [Theory]
+        [Theory]
         [InlineData(new object[] { Map, "a", 1, "b", new object[] { 2, 3 } }, "a26161016162820203")]
         [InlineData(new object[] { Map, "a", new object[] { 2, 3, "b", new object[] { Map, "x", -1, "y", new object[] { "z", 0 } } } }, "a161618402036162a2617820617982617a00")]
         [InlineData(new object[] { "a", new object[] { Map, "b", "c" } }, "826161a161626163")]
@@ -384,5 +384,18 @@ public static void WriteStartMap_IndefiniteLength_NoPatching_UnsupportedConforma
             var writer = new CborWriter(conformanceMode, convertIndefiniteLengthEncodings: false);
             Assert.Throws<InvalidOperationException>(() => writer.WriteStartMap(null));
         }
+
+        [Fact]
+        public static void Write_TaggedEmptyMap_ShouldSucceed()
+        {
+            var writer = new CborWriter();
+
+            writer.WriteTag(CborTag.DateTimeString);
+            writer.WriteStartMap(0);
+            writer.WriteEndMap();
+
+            byte[] encoding = writer.Encode();
+            Assert.Equal("C0A0", encoding.ByteArrayToHex());
+        }
     }
 }