Do not trigger fallback mapping if not mapped

Check if the maps exist first.

Author: bootleq

autoload/cycle.vim

@@ -75,11 +75,14 @@ function! cycle#new(class_name, direction, count, ...) "{{{
   let matches = cycle#search(a:class_name, {'direction': a:direction, 'count': a:count, 'groups': groups})
 
   if empty(matches)
-    return s:fallback(
-          \   a:class_name == 'v' ? "'<,'>" : '',
-          \   a:direction,
-          \   a:count
-          \ )
+    if len(mapcheck('<Plug>CycleFallback')) > 0
+      call s:fallback(
+            \   a:class_name == 'v' ? "'<,'>" : '',
+            \   a:direction,
+            \   a:count
+            \ )
+    endif
+    return
   endif
 
   let ctx = {

test/fallback.vimspec

@@ -0,0 +1,27 @@
+Describe Fallback
+  Before each
+    new
+  End
+
+  After each
+    if len(mapcheck('<Plug>CycleFallbackNext')) > 0
+      unmap <Plug>CycleFallbackNext
+    endif
+    bwipeout!
+  End
+
+  It does nothing by default
+    call setline(1, '200')
+    execute 'normal \a'
+    Assert Equals(getline(1), '200')
+  End
+
+  It triggers fallback mapping in Normal mode
+    noremap <silent> <Plug>CycleFallbackNext <C-A>
+
+    call setline(1, '200')
+    execute 'normal \a'
+
+    Assert Equals(getline(1), '201')
+  End
+End