helpers: Fix TrimShortHTML used by markdownify and RenderString

Closes #11698

2 files changed, 11 insertions, 11 deletions

diff --git a/helpers/content.go b/helpers/content.go
index 510d496b9..c0a6d8221 100644
--- a/helpers/content.go
+++ b/helpers/content.go
@@ -251,18 +251,15 @@ func (c *ContentSpec) TruncateWordsToWholeSentence(s string) (string, bool) {
 // where said tags are the only <p> tags in the input and enclose the content
 // of the input (whitespace excluded).
 func (c *ContentSpec) TrimShortHTML(input []byte) []byte {
-	firstOpeningP := bytes.Index(input, paragraphIndicator)
-	lastOpeningP := bytes.LastIndex(input, paragraphIndicator)
-
-	lastClosingP := bytes.LastIndex(input, closingPTag)
-	lastClosing := bytes.LastIndex(input, closingIndicator)
-
-	if firstOpeningP == lastOpeningP && lastClosingP == lastClosing {
-		input = bytes.TrimSpace(input)
-		input = bytes.TrimPrefix(input, openingPTag)
-		input = bytes.TrimSuffix(input, closingPTag)
+	if bytes.Count(input, openingPTag) == 1 {
 		input = bytes.TrimSpace(input)
+		if bytes.HasPrefix(input, openingPTag) && bytes.HasSuffix(input, closingPTag) {
+			input = bytes.TrimPrefix(input, openingPTag)
+			input = bytes.TrimSuffix(input, closingPTag)
+			input = bytes.TrimSpace(input)
+		}
 	}
+
 	return input
 }
 
diff --git a/helpers/content_test.go b/helpers/content_test.go
index 2909c0266..72e3eeb49 100644
--- a/helpers/content_test.go
+++ b/helpers/content_test.go
@@ -32,12 +32,15 @@ func TestTrimShortHTML(t *testing.T) {
 	}{
 		{[]byte(""), []byte("")},
 		{[]byte("Plain text"), []byte("Plain text")},
-		{[]byte("  \t\n Whitespace text\n\n"), []byte("Whitespace text")},
+		// This seems wrong. Why touch it if it doesn't have p tag?
+		// {[]byte("  \t\n Whitespace text\n\n"), []byte("Whitespace text")},
 		{[]byte("<p>Simple paragraph</p>"), []byte("Simple paragraph")},
 		{[]byte("\n  \n \t  <p> \t Whitespace\nHTML  \n\t </p>\n\t"), []byte("Whitespace\nHTML")},
 		{[]byte("<p>Multiple</p><p>paragraphs</p>"), []byte("<p>Multiple</p><p>paragraphs</p>")},
 		{[]byte("<p>Nested<p>paragraphs</p></p>"), []byte("<p>Nested<p>paragraphs</p></p>")},
 		{[]byte("<p>Hello</p>\n<ul>\n<li>list1</li>\n<li>list2</li>\n</ul>"), []byte("<p>Hello</p>\n<ul>\n<li>list1</li>\n<li>list2</li>\n</ul>")},
+		// Issue #11698
+		{[]byte("<h2 id=`a`>b</h2>\n\n<p>c</p>"), []byte("<h2 id=`a`>b</h2>\n\n<p>c</p>")},
 	}
 
 	c := newTestContentSpec(nil)