Only include RenderInlineContent.image if it resolves

Currently we resolve and diagnose image references but
include the `RenderInlineContent.image` regardless. This cleans up
that behavior to only include it in the case where the image resolves.

Author: ethan-kusters

Sources/SwiftDocC/Model/Rendering/RenderContentCompiler.swift

@@ -90,7 +90,9 @@ struct RenderContentCompiler: MarkupVisitor {
         altText: String?,
         caption: [RenderInlineContent]?
     ) -> [RenderContent] {
-        let imageIdentifier = resolveImage(source: source, altText: altText)
+        guard let imageIdentifier = resolveImage(source: source, altText: altText) else {
+            return []
+        }
 
         var metadata: RenderContentMetadata?
         if let caption = caption {
@@ -100,21 +102,23 @@ struct RenderContentCompiler: MarkupVisitor {
         return [RenderInlineContent.image(identifier: imageIdentifier, metadata: metadata)]
     }
 
-    mutating func resolveImage(source: String, altText: String? = nil) -> RenderReferenceIdentifier {
+    mutating func resolveImage(source: String, altText: String? = nil) -> RenderReferenceIdentifier? {
         let unescapedSource = source.removingPercentEncoding ?? source
         let imageIdentifier: RenderReferenceIdentifier = .init(unescapedSource)
-        if let resolvedImages = context.resolveAsset(
+        guard let resolvedImages = context.resolveAsset(
             named: unescapedSource,
             in: identifier,
             withType: .image
-        ) {
-            imageReferences[unescapedSource] = ImageReference(
-                identifier: imageIdentifier,
-                altText: altText,
-                imageAsset: resolvedImages
-            )
+        ) else {
+            return nil
         }
 
+        imageReferences[unescapedSource] = ImageReference(
+            identifier: imageIdentifier,
+            altText: altText,
+            imageAsset: resolvedImages
+        )
+        
         return imageIdentifier
     }
 

Tests/SwiftDocCTests/Model/SemaToRenderNodeTests.swift

@@ -2692,7 +2692,6 @@ Document
                 RenderBlockContent.heading(.init(level: 2, text: "Discussion", anchor: "discussion")),
                 .paragraph(.init(inlineContent: [
                     .text("Doc extension discussion. Missing: "),
-                    .image(identifier: RenderReferenceIdentifier("my-inherited-image.png"), metadata: nil),
                     .text("."),
                 ]))
             ])
@@ -2867,7 +2866,6 @@ Document
                 RenderBlockContent.heading(.init(level: 2, text: "Discussion", anchor: "discussion")),
                 .paragraph(.init(inlineContent: [
                     .text("Inherited discussion. Missing: "),
-                    .image(identifier: RenderReferenceIdentifier("my-inherited-image.png"), metadata: nil),
                     .text("."),
                 ])),
             ])