SA1629 should allow full-sentence links instead of forcing the period to glow white

StyleCop.Analyzers/StyleCop.Analyzers.Test/DocumentationRules/SA1629UnitTests.cs

@@ -544,6 +544,23 @@ public interface ITest
             await VerifyCSharpFixAsync(testCode, expected, fixedTestCode, default).ConfigureAwait(false);
         }
 
+        [Theory]
+        [InlineData("a")]
+        [InlineData("see")]
+        [InlineData("seealso")]
+        public async Task TestFullSentenceLinkAsync(string tag)
+        {
+            var testCode = $@"
+/// <summary>
+/// <{tag} href=""someurl"">Periods aren't required to glow white at the end of a full-sentence link.</{tag}>
+/// </summary>
+public interface ITest
+{{
+}}
+";
+            await VerifyCSharpDiagnosticAsync(testCode, DiagnosticResult.EmptyDiagnosticResults, default).ConfigureAwait(false);
+        }
+
         [Theory]
         [InlineData(",")]
         [InlineData(";")]

StyleCop.Analyzers/StyleCop.Analyzers/DocumentationRules/SA1629DocumentationTextMustEndWithAPeriod.cs

@@ -125,10 +125,7 @@ private static void HandleSectionOrBlockXmlElement(SyntaxNodeAnalysisContext con
 
                         if (!string.IsNullOrEmpty(textWithoutTrailingWhitespace))
                         {
-                            if (!textWithoutTrailingWhitespace.EndsWith(".", StringComparison.Ordinal)
-                                && !textWithoutTrailingWhitespace.EndsWith(".)", StringComparison.Ordinal)
-                                && (startingWithFinalParagraph || !textWithoutTrailingWhitespace.EndsWith(":", StringComparison.Ordinal))
-                                && !textWithoutTrailingWhitespace.EndsWith("-or-", StringComparison.Ordinal))
+                            if (IsMissingRequiredPeriod(textWithoutTrailingWhitespace, startingWithFinalParagraph))
                             {
                                 int spanStart = textToken.SpanStart + textWithoutTrailingWhitespace.Length;
                                 ImmutableDictionary<string, string> properties = null;
@@ -162,10 +159,15 @@ void SetReplaceChar()
                 }
                 else if (xmlElement.Content[i].IsInlineElement() && !currentParagraphDone)
                 {
-                    // Treat empty XML elements as a "word not ending with a period"
-                    var location = Location.Create(xmlElement.SyntaxTree, new TextSpan(xmlElement.Content[i].Span.End, 1));
-                    context.ReportDiagnostic(Diagnostic.Create(Descriptor, location));
-                    currentParagraphDone = true;
+                    var lastTextElement = XmlCommentHelper.TryGetLastTextElementWithContent(xmlElement.Content[i]);
+
+                    if (lastTextElement is null // Treat empty XML elements as a "word not ending with a period"
+                        || IsMissingRequiredPeriod(lastTextElement.TextTokens.Last().Text.TrimEnd(' ', '\r', '\n'), startingWithFinalParagraph))
+                    {
+                        var location = Location.Create(xmlElement.SyntaxTree, new TextSpan(xmlElement.Content[i].Span.End, 1));
+                        context.ReportDiagnostic(Diagnostic.Create(Descriptor, location));
+                        currentParagraphDone = true;
+                    }
                 }
                 else if (xmlElement.Content[i] is XmlElementSyntax childXmlElement)
                 {
@@ -198,5 +200,13 @@ void SetReplaceChar()
                 }
             }
         }
+
+        private static bool IsMissingRequiredPeriod(string textWithoutTrailingWhitespace, bool startingWithFinalParagraph)
+        {
+            return !textWithoutTrailingWhitespace.EndsWith(".", StringComparison.Ordinal)
+                && !textWithoutTrailingWhitespace.EndsWith(".)", StringComparison.Ordinal)
+                && (startingWithFinalParagraph || !textWithoutTrailingWhitespace.EndsWith(":", StringComparison.Ordinal))
+                && !textWithoutTrailingWhitespace.EndsWith("-or-", StringComparison.Ordinal);
+        }
     }
 }

StyleCop.Analyzers/StyleCop.Analyzers/Helpers/XmlCommentHelper.cs

@@ -191,6 +191,37 @@ internal static XmlTextSyntax TryGetFirstTextElementWithContent(XmlNodeSyntax no
             return null;
         }
 
+        /// <summary>
+        /// Returns the last <see cref="XmlTextSyntax"/> which is not simply empty or whitespace.
+        /// </summary>
+        /// <param name="node">The XML content to search.</param>
+        /// <returns>The last <see cref="XmlTextSyntax"/> which is not simply empty or whitespace, or
+        /// <see langword="null"/> if no such element exists.</returns>
+        internal static XmlTextSyntax TryGetLastTextElementWithContent(XmlNodeSyntax node)
+        {
+            if (node is XmlEmptyElementSyntax)
+            {
+                return null;
+            }
+            else if (node is XmlTextSyntax xmlText)
+            {
+                return !IsConsideredEmpty(node) ? xmlText : null;
+            }
+            else if (node is XmlElementSyntax xmlElement)
+            {
+                for (var i = xmlElement.Content.Count - 1; i >= 0; i--)
+                {
+                    var nestedContent = TryGetFirstTextElementWithContent(xmlElement.Content[i]);
+                    if (nestedContent != null)
+                    {
+                        return nestedContent;
+                    }
+                }
+            }
+
+            return null;
+        }
+
         /// <summary>
         /// Checks if a <see cref="SyntaxTrivia"/> contains a <see cref="DocumentationCommentTriviaSyntax"/> and returns
         /// <see langword="true"/> if it is considered empty.