Merge pull request #7682 from tk0miya/viewcode_missing_reference

viewcode: Fix viewcode raises NoUri error on resolving phase except on HTML builders

sphinx/ext/viewcode.py

@@ -131,8 +131,10 @@ def env_merge_info(app: Sphinx, env: BuildEnvironment, docnames: Iterable[str],
 
 def missing_reference(app: Sphinx, env: BuildEnvironment, node: Element, contnode: Node
                       ) -> Node:
-    # resolve our "viewcode" reference nodes -- they need special treatment
-    if node['reftype'] == 'viewcode':
+    if app.builder.format != 'html':
+        return None
+    elif node['reftype'] == 'viewcode':
+        # resolve our "viewcode" reference nodes -- they need special treatment
         return make_refnode(app.builder, node['refdoc'], node['reftarget'],
                             node['refid'], contnode)