Keep Objective-C categories of non-modular classes apart

CHANGELOG.md

@@ -40,6 +40,12 @@
   [Minh Nguyễn](https://github.com/1ec5)
   [#706](https://github.com/realm/jazzy/issues/706)
 
+* Fix issue where multiple Objective-C categories of the same external class
+  in different files were merged into one and named after the first category
+  found.  
+  [Minh Nguyễn](https://github.com/1ec5)
+  [#539](https://github.com/realm/jazzy/issues/539)
+
 ## 0.7.3
 
 ##### Breaking

lib/jazzy/sourcekitten.rb

@@ -390,7 +390,7 @@ def self.doc_coverage
     # Merges redundant declarations when documenting podspecs.
     def self.deduplicate_declarations(declarations)
       duplicate_groups = declarations
-                         .group_by { |d| deduplication_key(d) }
+                         .group_by { |d| deduplication_key(d, declarations) }
                          .values
 
       duplicate_groups.map do |group|
@@ -400,10 +400,11 @@ def self.deduplicate_declarations(declarations)
     end
 
     # Two declarations get merged if they have the same deduplication key.
-    def self.deduplication_key(decl)
+    def self.deduplication_key(decl, root_decls)
       if decl.type.swift_extensible? || decl.type.swift_extension?
         [decl.usr, decl.name]
-      elsif decl.type.objc_class? || decl.type.objc_category?
+      elsif decl.type.objc_class? || \
+          (decl.type.objc_category? && name_match(decl.objc_category_name[0], root_decls))
         name, _ = decl.objc_category_name || decl.name
         [name, :objc_class_and_categories]
       else