SI-5795 empty scaladoc tags should be omitted from output

Empty scaladoc tags, like `@param`, `@return`, `@version`, etc. should
be omitted from the output when they have no meaning by themselves.

They are still parsed, for validation (warning that a tag doesn't
exist and so on), but are removed, if empty, when building the Comment.

The only ones that stay even when empty are `@deprecated`, so that the
class name can be striked-through ("Deprecated" also appears in the
header, even if there is no message with it), and `@throws`.

1 files changed, 8 insertions, 8 deletions

diff --git a/src/scaladoc/scala/tools/nsc/doc/base/CommentFactoryBase.scala b/src/scaladoc/scala/tools/nsc/doc/base/CommentFactoryBase.scala
index 42ca98dc7a..fb4ed34571 100755
--- a/src/scaladoc/scala/tools/nsc/doc/base/CommentFactoryBase.scala
+++ b/src/scaladoc/scala/tools/nsc/doc/base/CommentFactoryBase.scala
@@ -318,18 +318,18 @@ trait CommentFactoryBase { this: MemberLookupBase =>
         val bodyTags: mutable.Map[TagKey, List[Body]] =
           mutable.Map(tagsWithoutDiagram mapValues {tag => tag map (parseWikiAtSymbol(_, pos, site))} toSeq: _*)
 
-        def oneTag(key: SimpleTagKey): Option[Body] =
+        def oneTag(key: SimpleTagKey, filterEmpty: Boolean = true): Option[Body] =
           ((bodyTags remove key): @unchecked) match {
-            case Some(r :: rs) =>
+            case Some(r :: rs) if !(filterEmpty && r.blocks.isEmpty) =>
               if (!rs.isEmpty) reporter.warning(pos, "Only one '@" + key.name + "' tag is allowed")
               Some(r)
-            case None => None
+            case _ => None
           }
 
         def allTags(key: SimpleTagKey): List[Body] =
-          (bodyTags remove key) getOrElse Nil
+          (bodyTags remove key).getOrElse(Nil).filterNot(_.blocks.isEmpty)
 
-        def allSymsOneTag(key: TagKey): Map[String, Body] = {
+        def allSymsOneTag(key: TagKey, filterEmpty: Boolean = true): Map[String, Body] = {
           val keys: Seq[SymbolTagKey] =
             bodyTags.keys.toSeq flatMap {
               case stk: SymbolTagKey if (stk.name == key.name) => Some(stk)
@@ -345,11 +345,11 @@ trait CommentFactoryBase { this: MemberLookupBase =>
                 reporter.warning(pos, "Only one '@" + key.name + "' tag for symbol " + key.symbol + " is allowed")
               (key.symbol, bs.head)
             }
-          Map.empty[String, Body] ++ pairs
+          Map.empty[String, Body] ++ (if (filterEmpty) pairs.filterNot(_._2.blocks.isEmpty) else pairs)
         }
 
         def linkedExceptions: Map[String, Body] = {
-          val m = allSymsOneTag(SimpleTagKey("throws"))
+          val m = allSymsOneTag(SimpleTagKey("throws"), filterEmpty = false)
 
           m.map { case (name,body) =>
             val link = memberLookup(pos, name, site)
@@ -375,7 +375,7 @@ trait CommentFactoryBase { this: MemberLookupBase =>
           version0        = oneTag(SimpleTagKey("version")),
           since0          = oneTag(SimpleTagKey("since")),
           todo0           = allTags(SimpleTagKey("todo")),
-          deprecated0     = oneTag(SimpleTagKey("deprecated")),
+          deprecated0     = oneTag(SimpleTagKey("deprecated"), filterEmpty = false),
           note0           = allTags(SimpleTagKey("note")),
           example0        = allTags(SimpleTagKey("example")),
           constructor0    = oneTag(SimpleTagKey("constructor")),