Add nullability annotation on CacheControlHeaderValue (#74863)

* Add nullability annotation on CacheControlHeaderValue Add nullability annotation on CacheControlHeaderValue.TryParse inside System.Net.Http Fix #74061 * Returns empty value instead of null * Parsing returns empty values instead of null * Remove useless tests + null-forgiving operator * Remove null-forgiving and add nullable return type
dotnet · Sep 5, 2022 · 3ec9617 · 3ec9617
1 parent b90a734
commit 3ec9617
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Showing 3 changed files with 20 additions and 4 deletions.
diff --git a/src/libraries/System.Net.Http/ref/System.Net.Http.cs b/src/libraries/System.Net.Http/ref/System.Net.Http.cs
@@ -491,7 +491,7 @@ public CacheControlHeaderValue() { }
         public static System.Net.Http.Headers.CacheControlHeaderValue Parse(string? input) { throw null; }
         object System.ICloneable.Clone() { throw null; }
         public override string ToString() { throw null; }
-        public static bool TryParse(string? input, out System.Net.Http.Headers.CacheControlHeaderValue? parsedValue) { throw null; }
+        public static bool TryParse(string? input, [System.Diagnostics.CodeAnalysis.NotNullWhenAttribute(true)] out System.Net.Http.Headers.CacheControlHeaderValue? parsedValue) { throw null; }
     }
     public partial class ContentDispositionHeaderValue : System.ICloneable
     {

diff --git a/src/libraries/System.Net.Http/src/System/Net/Http/Headers/CacheControlHeaderValue.cs b/src/libraries/System.Net.Http/src/System/Net/Http/Headers/CacheControlHeaderValue.cs
@@ -364,17 +364,17 @@ public override int GetHashCode()
         public static CacheControlHeaderValue Parse(string? input)
         {
             int index = 0;
-            return (CacheControlHeaderValue)CacheControlHeaderParser.Parser.ParseValue(input, null, ref index);
+            return (CacheControlHeaderValue)CacheControlHeaderParser.Parser.ParseValue(input, null, ref index) ?? new CacheControlHeaderValue();
         }
 
-        public static bool TryParse(string? input, out CacheControlHeaderValue? parsedValue)
+        public static bool TryParse(string? input, [NotNullWhen(true)] out CacheControlHeaderValue? parsedValue)
         {
             int index = 0;
             parsedValue = null;
 
             if (CacheControlHeaderParser.Parser.TryParseValue(input, null, ref index, out object? output))
             {
-                parsedValue = (CacheControlHeaderValue?)output;
+                parsedValue = (CacheControlHeaderValue?)output ?? new CacheControlHeaderValue();
                 return true;
             }
             return false;

diff --git a/src/libraries/System.Net.Http/tests/UnitTests/Headers/CacheControlHeaderValueTest.cs b/src/libraries/System.Net.Http/tests/UnitTests/Headers/CacheControlHeaderValueTest.cs
@@ -628,6 +628,22 @@ public void Parse_SetOfInvalidValueStrings_Throws()
             CheckInvalidParse("\u4F1A", 0);
         }
 
+
+        [Theory]
+        [InlineData(null)]
+        [InlineData("")]
+        [InlineData(" ")]
+        [InlineData(",")]
+        [InlineData(",,")]
+        [InlineData(" , , ")]
+        public void CacheControlHeaderValue_EmptyValue_Parsed(string value)
+        {
+            Assert.NotNull(CacheControlHeaderValue.Parse(value));
+
+            Assert.True(CacheControlHeaderValue.TryParse(value, out CacheControlHeaderValue headerValue));
+            Assert.NotNull(headerValue);
+        }
+
         [Fact]
         public void TryParse_SetOfValidValueStrings_ParsedCorrectly()
         {