Fix nullability indicators for the Parse/TryParse overloads (#1446)

(UnitParser, QuantityParser, Quantity)

fixes #1445

---------

Co-authored-by: Andreas Gullberg Larsen <andreas.larsen84@gmail.com>

CodeGen/Generators/UnitsNetGen/QuantityGenerator.cs

@@ -517,7 +517,7 @@ private void GenerateStaticParseMethods()
         /// <example>
         ///     Length.Parse(""5.5 m"", CultureInfo.GetCultureInfo(""en-US""));
         /// </example>
-        public static bool TryParse(string? str, out {_quantity.Name} result)
+        public static bool TryParse([NotNullWhen(true)]string? str, out {_quantity.Name} result)
         {{
             return TryParse(str, null, out result);
         }}
@@ -532,7 +532,7 @@ public static bool TryParse(string? str, out {_quantity.Name} result)
         ///     Length.Parse(""5.5 m"", CultureInfo.GetCultureInfo(""en-US""));
         /// </example>
         /// <param name=""provider"">Format to use when parsing number and unit. Defaults to <see cref=""CultureInfo.CurrentCulture"" /> if null.</param>
-        public static bool TryParse(string? str, IFormatProvider? provider, out {_quantity.Name} result)
+        public static bool TryParse([NotNullWhen(true)]string? str, IFormatProvider? provider, out {_quantity.Name} result)
         {{
             return QuantityParser.Default.TryParse<{_quantity.Name}, {_unitEnumName}>(
                 str,
@@ -571,7 +571,7 @@ public static bool TryParse(string? str, IFormatProvider? provider, out {_quanti
         }}
 
         /// <inheritdoc cref=""TryParseUnit(string,IFormatProvider,out UnitsNet.Units.{_unitEnumName})""/>
-        public static bool TryParseUnit(string str, out {_unitEnumName} unit)
+        public static bool TryParseUnit([NotNullWhen(true)]string? str, out {_unitEnumName} unit)
         {{
             return TryParseUnit(str, null, out unit);
         }}
@@ -586,7 +586,7 @@ public static bool TryParseUnit(string str, out {_unitEnumName} unit)
         ///     Length.TryParseUnit(""m"", CultureInfo.GetCultureInfo(""en-US""));
         /// </example>
         /// <param name=""provider"">Format to use when parsing number and unit. Defaults to <see cref=""CultureInfo.CurrentCulture"" /> if null.</param>
-        public static bool TryParseUnit(string str, IFormatProvider? provider, out {_unitEnumName} unit)
+        public static bool TryParseUnit([NotNullWhen(true)]string? str, IFormatProvider? provider, out {_unitEnumName} unit)
         {{
             return UnitParser.Default.TryParse<{_unitEnumName}>(str, provider, out unit);
         }}

CodeGen/Generators/UnitsNetGen/StaticQuantityGenerator.cs

@@ -100,7 +100,7 @@ public static bool TryFrom(double value, Enum? unit, [NotNullWhen(true)] out IQu
         /// <param name=""quantityString"">Quantity string representation, such as ""1.5 kg"". Must be compatible with given quantity type.</param>
         /// <param name=""quantity"">The resulting quantity if successful, otherwise <c>default</c>.</param>
         /// <returns>The parsed quantity.</returns>
-        public static bool TryParse(IFormatProvider? formatProvider, Type quantityType, string quantityString, [NotNullWhen(true)] out IQuantity? quantity)
+        public static bool TryParse(IFormatProvider? formatProvider, Type quantityType, [NotNullWhen(true)] string? quantityString, [NotNullWhen(true)] out IQuantity? quantity)
         {
             quantity = default(IQuantity);
 

UnitsNet.Tests/QuantityParserTests.cs

@@ -1,7 +1,9 @@
-// Licensed under MIT No Attribution, see LICENSE file at the root.
+// Licensed under MIT No Attribution, see LICENSE file at the root.
 // Copyright 2013 Andreas Gullberg Larsen (andreas.larsen84@gmail.com). Maintained at https://github.com/angularsen/UnitsNet.
 
+using System.Globalization;
 using UnitsNet.Tests.CustomQuantities;
+using UnitsNet.Units;
 using Xunit;
 
 namespace UnitsNet.Tests
@@ -87,5 +89,24 @@ public void TryParse_MappedCustomUnit()
             Assert.Equal(1, q.Value);
         }
 
+        [Fact]
+        public void TryParse_NullString_Returns_False()
+        {
+            QuantityParser quantityParser = UnitsNetSetup.Default.QuantityParser;
+
+            var success = quantityParser.TryParse<Mass, MassUnit>(null, null, Mass.From, out Mass _);
+
+            Assert.False(success);
+        }
+
+        [Fact]
+        public void TryParse_WithInvalidValue_Returns_False()
+        {
+            QuantityParser quantityParser = UnitsNetSetup.Default.QuantityParser;
+
+            var success = quantityParser.TryParse<Mass, MassUnit>("XX kg", CultureInfo.InvariantCulture, Mass.From, out Mass _);
+
+            Assert.False(success);
+        }
     }
 }

UnitsNet.Tests/UnitParserTests.cs

@@ -137,5 +137,20 @@ public void Parse_MappedCustomUnit()
 
             Assert.Equal(HowMuchUnit.Some, parsedUnit);
         }
+
+        [Fact]
+        public void TryParse_WithNullAbbreviation_ReturnsFalse()
+        {
+            UnitParser unitParser = UnitsNetSetup.Default.UnitParser;
+            Assert.Multiple(() =>
+            {
+                var success = unitParser.TryParse(null, out LengthUnit unit);
+                Assert.False(success);
+            }, () =>
+            {
+                var success = unitParser.TryParse(null, typeof(LengthUnit), out Enum? _);
+                Assert.False(success);
+            });
+        }
     }
 }

UnitsNet/CustomCode/QuantityParser.cs

@@ -133,7 +133,7 @@ public bool TryParse<TQuantity, TUnitType>(string? str,
         /// <exception cref="ArgumentNullException">The string was null.</exception>
         /// <exception cref="FormatException">Failed to parse quantity.</exception>
         [SuppressMessage("ReSharper", "UseStringInterpolation")]
-        public bool TryParse<TQuantity, TUnitType>(string str,
+        public bool TryParse<TQuantity, TUnitType>(string? str,
             IFormatProvider? formatProvider,
             QuantityFromDelegate<TQuantity, TUnitType> fromDelegate,
             out IQuantity? result)

UnitsNet/CustomCode/UnitParser.cs

@@ -62,7 +62,7 @@ public TUnitType Parse<TUnitType>(string unitAbbreviation, IFormatProvider? form
         /// <returns>Unit enum value, such as <see cref="MassUnit.Kilogram" />.</returns>
         /// <exception cref="UnitNotFoundException">No units match the abbreviation.</exception>
         /// <exception cref="AmbiguousUnitParseException">More than one unit matches the abbreviation.</exception>
-        public Enum Parse(string? unitAbbreviation, Type unitType, IFormatProvider? formatProvider = null)
+        public Enum Parse(string unitAbbreviation, Type unitType, IFormatProvider? formatProvider = null)
         {
             if (unitAbbreviation == null) throw new ArgumentNullException(nameof(unitAbbreviation));
             unitAbbreviation = unitAbbreviation.Trim();
@@ -138,7 +138,7 @@ internal static string NormalizeUnitString(string unitAbbreviation)
         /// <param name="unit">The unit enum value as out result.</param>
         /// <typeparam name="TUnitType">Type of unit enum.</typeparam>
         /// <returns>True if successful.</returns>
-        public bool TryParse<TUnitType>(string unitAbbreviation, out TUnitType unit) where TUnitType : struct, Enum
+        public bool TryParse<TUnitType>([NotNullWhen(true)]string? unitAbbreviation, out TUnitType unit) where TUnitType : struct, Enum
         {
             return TryParse(unitAbbreviation, null, out unit);
         }
@@ -151,7 +151,7 @@ public bool TryParse<TUnitType>(string unitAbbreviation, out TUnitType unit) whe
         /// <param name="unit">The unit enum value as out result.</param>
         /// <typeparam name="TUnitType">Type of unit enum.</typeparam>
         /// <returns>True if successful.</returns>
-        public bool TryParse<TUnitType>(string? unitAbbreviation, IFormatProvider? formatProvider, out TUnitType unit) where TUnitType : struct, Enum
+        public bool TryParse<TUnitType>([NotNullWhen(true)]string? unitAbbreviation, IFormatProvider? formatProvider, out TUnitType unit) where TUnitType : struct, Enum
         {
             unit = default;
 
@@ -169,7 +169,7 @@ public bool TryParse<TUnitType>(string? unitAbbreviation, IFormatProvider? forma
         /// <param name="unitType">Type of unit enum.</param>
         /// <param name="unit">The unit enum value as out result.</param>
         /// <returns>True if successful.</returns>
-        public bool TryParse(string unitAbbreviation, Type unitType, [NotNullWhen(true)] out Enum? unit)
+        public bool TryParse([NotNullWhen(true)] string? unitAbbreviation, Type unitType, [NotNullWhen(true)] out Enum? unit)
         {
             return TryParse(unitAbbreviation, unitType, null, out unit);
         }
@@ -182,7 +182,7 @@ public bool TryParse(string unitAbbreviation, Type unitType, [NotNullWhen(true)]
         /// <param name="formatProvider">The format provider to use for lookup. Defaults to <see cref="CultureInfo.CurrentCulture" /> if null.</param>
         /// <param name="unit">The unit enum value as out result.</param>
         /// <returns>True if successful.</returns>
-        public bool TryParse(string? unitAbbreviation, Type unitType, IFormatProvider? formatProvider, [NotNullWhen(true)] out Enum? unit)
+        public bool TryParse([NotNullWhen(true)] string? unitAbbreviation, Type unitType, IFormatProvider? formatProvider, [NotNullWhen(true)] out Enum? unit)
         {
             if (unitAbbreviation == null)
             {