Merge pull request #7523 from hayaksi1/fix/1874-empty-formatted-body

Fall back to the message body when the formatted body has nothing to render

libraries/matrixui/src/main/kotlin/io/element/android/libraries/matrix/ui/messages/ToHtmlDocument.kt

@@ -19,7 +19,8 @@ import org.jsoup.safety.Safelist
 
 /**
  * Converts the HTML string [FormattedBody.body] to a [Document] by parsing it.
- * If the message is not formatted or the format is not [MessageFormat.HTML] we return `null`.
+ * If the message is not formatted, the format is not [MessageFormat.HTML], or nothing renderable is left once the
+ * unsupported tags have been removed, we return `null` so that the plain text body is used instead.
  *
  * This will also make sure mentions are prefixed with `@`.
  *
@@ -44,7 +45,7 @@ fun FormattedBody.toHtmlDocument(
             // Prepend `@` to mentions
             fixMentions(dom, permalinkParser)
 
-            dom
+            dom.takeIf { it.text().isNotBlank() }
         }
 }
 

libraries/matrixui/src/test/kotlin/io/element/android/libraries/matrix/ui/messages/ToHtmlDocumentTest.kt

@@ -103,4 +103,28 @@ class ToHtmlDocumentTest : RobolectricTest() {
         })
         assertThat(document?.text()).isEqualTo("Hey Alice!")
     }
+
+    @Test
+    fun `toHtmlDocument - returns null if the body only contains unsupported tags`() {
+        val body = FormattedBody(
+            format = MessageFormat.HTML,
+            body = "<img data-mx-emoticon src=\"mxc://matrix.org/anImage\" height=\"32\" width=\"32\" alt=\"\uD83D\uDE1C\" />"
+        )
+
+        val document = body.toHtmlDocument(permalinkParser = FakePermalinkParser())
+
+        assertThat(document).isNull()
+    }
+
+    @Test
+    fun `toHtmlDocument - returns a Document if some text survives next to unsupported tags`() {
+        val body = FormattedBody(
+            format = MessageFormat.HTML,
+            body = "Look at this <img src=\"mxc://matrix.org/anImage\" alt=\"cat\" />!"
+        )
+
+        val document = body.toHtmlDocument(permalinkParser = FakePermalinkParser())
+
+        assertThat(document?.text()).isEqualTo("Look at this !")
+    }
 }

libraries/matrixui/src/test/kotlin/io/element/android/libraries/matrix/ui/messages/ToPlainTextTest.kt

@@ -149,4 +149,16 @@ class ToPlainTextTest : RobolectricTest() {
         )
         assertThat(messageType.toPlainText(permalinkParser = FakePermalinkParser())).isEqualTo("This is the message content.")
     }
+
+    @Test
+    fun `TextMessageType toPlainText - returns the body if the formatted one only contains an image`() {
+        val messageType = TextMessageType(
+            body = "\uD83D\uDE1C",
+            formatted = FormattedBody(
+                format = MessageFormat.HTML,
+                body = "<img data-mx-emoticon src=\"mxc://matrix.org/anImage\" height=\"32\" width=\"32\" alt=\"\uD83D\uDE1C\" />"
+            )
+        )
+        assertThat(messageType.toPlainText(permalinkParser = FakePermalinkParser())).isEqualTo("\uD83D\uDE1C")
+    }
 }