Align null behaviour for DateTimes

src/Hl7.Fhir.Base/CompatibilitySuppressions.xml

@@ -344,6 +344,13 @@
     <Right>lib/net8.0/Hl7.Fhir.Base.dll</Right>
     <IsBaselineSuppression>true</IsBaselineSuppression>
   </Suppression>
+  <Suppression>
+    <DiagnosticId>CP0002</DiagnosticId>
+    <Target>M:Hl7.Fhir.Model.Date.ToDateTimeOffset</Target>
+    <Left>lib/net8.0/Hl7.Fhir.Base.dll</Left>
+    <Right>lib/net8.0/Hl7.Fhir.Base.dll</Right>
+    <IsBaselineSuppression>true</IsBaselineSuppression>
+  </Suppression>
   <Suppression>
     <DiagnosticId>CP0002</DiagnosticId>
     <Target>M:Hl7.Fhir.Model.Meta.get_ProfileElement</Target>

src/Hl7.Fhir.Base/Model/Date.cs

@@ -27,129 +27,121 @@ POSSIBILITY OF SUCH DAMAGE.
 
 
 */
+#nullable enable
 
 using System;
 using System.Diagnostics.CodeAnalysis;
 using P = Hl7.Fhir.ElementModel.Types;
 
-#nullable enable
+namespace Hl7.Fhir.Model;
 
-namespace Hl7.Fhir.Model
+public partial class Date
 {
-    public partial class Date
+    public Date(int year, int month, int day)
+        : this(string.Format(System.Globalization.CultureInfo.InvariantCulture, FhirDateTime.FMT_YEARMONTHDAY, year, month, day))
     {
-        public Date(int year, int month, int day)
-            : this(string.Format(System.Globalization.CultureInfo.InvariantCulture, FhirDateTime.FMT_YEARMONTHDAY, year, month, day))
-        {
-        }
+    }
 
-        public Date(int year, int month)
-            : this(string.Format(System.Globalization.CultureInfo.InvariantCulture, FhirDateTime.FMT_YEARMONTH, year, month))
-        {
-        }
+    public Date(int year, int month)
+        : this(string.Format(System.Globalization.CultureInfo.InvariantCulture, FhirDateTime.FMT_YEARMONTH, year, month))
+    {
+    }
 
-        public Date(int year) : this(string.Format(System.Globalization.CultureInfo.InvariantCulture, FhirDateTime.FMT_YEAR, year))
-        {
-        }
+    public Date(int year) : this(string.Format(System.Globalization.CultureInfo.InvariantCulture, FhirDateTime.FMT_YEAR, year))
+    {
+    }
 
-        public static Date FromDateTimeOffset(DateTimeOffset date) => new(date.Year, date.Month, date.Day);
+    public static Date FromDateTimeOffset(DateTimeOffset date) => new(date.Year, date.Month, date.Day);
 
-        /// <summary>
-        /// Gets the current date in the local timezone.
-        /// </summary>
-        public static Date Today() => FromDateTimeOffset(DateTimeOffset.Now);
+    /// <summary>
+    /// Gets the current date in the local timezone.
+    /// </summary>
+    public static Date Today() => FromDateTimeOffset(DateTimeOffset.Now);
 
-        /// <summary>
-        /// Gets the current date in UTC.
-        /// </summary>
-        public static Date UtcToday() => FromDateTimeOffset(DateTimeOffset.UtcNow);
+    /// <summary>
+    /// Gets the current date in UTC.
+    /// </summary>
+    public static Date UtcToday() => FromDateTimeOffset(DateTimeOffset.UtcNow);
 
-        [NonSerialized]  // To prevent binary serialization from serializing this field
-        private P.Date? _parsedValue = null;
+    [NonSerialized]  // To prevent binary serialization from serializing this field
+    private P.Date? _parsedValue = null;
 
-        // This is a sentinel value that marks that the current string representation is
-        // not parseable, so we don't have to try again. It's value is never used, it's just
-        // checked by reference.
-        private static readonly P.Date INVALID_VALUE = P.Date.FromDateTimeOffset(DateTimeOffset.MinValue);
+    // This is a sentinel value that marks that the current string representation is
+    // not parseable, so we don't have to try again. It's value is never used, it's just
+    // checked by reference.
+    private static readonly P.Date INVALID_VALUE = P.Date.FromDateTimeOffset(DateTimeOffset.MinValue);
 
-        /// <summary>
-        /// Converts a Fhir Date to a <see cref="P.Date"/>.
-        /// </summary>
-        /// <returns>true if the Fhir Date contains a valid date string, false otherwise.</returns>
-        public bool TryToDate([NotNullWhen(true)] out P.Date? date)
+    /// <summary>
+    /// Converts a Fhir Date to a <see cref="P.Date"/>.
+    /// </summary>
+    /// <returns>true if the Fhir Date contains a valid date string, false otherwise.</returns>
+    public bool TryToDate([NotNullWhen(true)] out P.Date? date)
+    {
+        if (_parsedValue is null)
         {
-            if (_parsedValue is null)
-            {
-                if (Value is not null && !(P.Date.TryParse(Value, out _parsedValue) && !_parsedValue!.HasOffset))
-                    _parsedValue = INVALID_VALUE;
-            }
-
-            if (hasInvalidParsedValue())
-            {
-                date = null;
-                return false;
-            }
-            else
-            {
-                date = _parsedValue!;
-                return true;
-            }
-
-            bool hasInvalidParsedValue() => ReferenceEquals(_parsedValue, INVALID_VALUE);
+            if (Value is not null && !(P.Date.TryParse(Value, out _parsedValue) && !_parsedValue!.HasOffset))
+                _parsedValue = INVALID_VALUE;
         }
 
-        /// <summary>
-        /// Converts a Fhir Date to a <see cref="P.Date"/>.
-        /// </summary>
-        /// <returns>The Date, or null if the <see cref="Value"/> is null.</returns>
-        /// <exception cref="FormatException">Thrown when the Value does not contain a valid FHIR Date.</exception>
-        public P.Date? ToDate() => TryToDate(out var dt) ? dt : throw new FormatException($"String '{Value}' was not recognized as a valid date.");
-
-        protected override void OnObjectValueChanged()
+        if (hasInvalidParsedValue())
         {
-            _parsedValue = null;
-            base.OnObjectValueChanged();
+            date = null;
+            return false;
         }
 
-        /// <summary>
-        /// Converts this Fhir Fhir Date to a <see cref="DateTimeOffset"/>.
-        /// </summary>
-        /// <returns>A DateTimeOffset filled out to midnight, january 1 (UTC) in case of a partial date.</returns>
-        public DateTimeOffset? ToDateTimeOffset()
-        {
-            if (Value == null) return null;   // Note: this behaviour is inconsistent with ToDateTimeOffset() in FhirDateTime
+        date = _parsedValue!;
+        return true;
 
-            // ToDateTimeOffset() will convert partial date/times by filling out to midnight/january 1 UTC
-            if (!TryToDate(out var dt))
-                throw new FormatException($"Date '{Value}' was not recognized as a valid datetime.");
+        bool hasInvalidParsedValue() => ReferenceEquals(_parsedValue, INVALID_VALUE);
+    }
 
-            // Since Value is not null and the parsed value is valid, dto will not be null
-            return dt!.ToDateTimeOffset(TimeSpan.Zero);
-        }
+    /// <summary>
+    /// Converts a Fhir Date to a <see cref="P.Date"/>.
+    /// </summary>
+    /// <returns>The Date, or null if the <see cref="Value"/> is null.</returns>
+    /// <exception cref="FormatException">Thrown when the Value does not contain a valid FHIR Date.</exception>
+    public P.Date ToDate() => TryToDate(out var dt) ? dt : throw new FormatException($"String '{Value}' was not recognized as a valid date.");
+
+    protected override void OnObjectValueChanged()
+    {
+        _parsedValue = null;
+        base.OnObjectValueChanged();
+    }
 
-        /// <summary>
-        /// Convert this Fhir Date to a <see cref="DateTimeOffset"/>.
-        /// </summary>
-        /// <returns>True if the value of the Fhir Date is not null and can be parsed as a DateTimeOffset, false otherwise.</returns>
-        public bool TryToDateTimeOffset(out DateTimeOffset dto)
+    /// <summary>
+    /// Converts this Fhir Fhir Date to a <see cref="DateTimeOffset"/>.
+    /// </summary>
+    /// <returns>A DateTimeOffset filled out to midnight, january 1 (UTC) in case of a partial date.</returns>
+    public DateTimeOffset ToDateTimeOffset()
+    {
+        if (Value == null) throw new InvalidOperationException("Date's value is null.");
+
+        // TryToDate() will convert partial date/times by filling out to midnight/january 1 UTC
+        if (!TryToDate(out var dt))
+            throw new FormatException($"Date '{Value}' was not recognized as a valid datetime.");
+
+        // Since Value is not null and the parsed value is valid, dto will not be null
+        return dt.ToDateTimeOffset(TimeSpan.Zero);
+    }
+
+    /// <summary>
+    /// Convert this Fhir Date to a <see cref="DateTimeOffset"/>.
+    /// </summary>
+    /// <returns>True if the value of the Fhir Date is not null and can be parsed as a DateTimeOffset, false otherwise.</returns>
+    public bool TryToDateTimeOffset(out DateTimeOffset dto)
+    {
+        if (Value is not null && TryToDate(out var dt))
         {
-            if (Value is not null && TryToDate(out var dt))
-            {
-                dto = dt.ToDateTimeOffset(TimeSpan.Zero);
-                return true;
-            }
-            else
-            {
-                dto = default;
-                return false;
-            }
+            dto = dt.ToDateTimeOffset(TimeSpan.Zero);
+            return true;
         }
 
-        /// <summary>
-        /// Checks whether the given literal is correctly formatted.
-        /// </summary>
-        public static bool IsValidValue(string value) => P.Date.TryParse(value, out var parsed) && !parsed.HasOffset;
+        dto = default;
+        return false;
     }
-}
 
-#nullable restore
+    /// <summary>
+    /// Checks whether the given literal is correctly formatted.
+    /// </summary>
+    public static bool IsValidValue(string value) => P.Date.TryParse(value, out var parsed) && !parsed.HasOffset;
+}