Fix the behavior of change-preview-window action (#3280)

* change-preview-window restores the initial preview window options,
  and overrides the properties that are specified
* However, 'hidden' property is treated differently. It is set to
  'false' if the specified properties of the action is non-empty.
* cf. toggle-preview takes the "current" preview window options and
  toggles the 'hidden' property.

src/options.go

@@ -1969,25 +1969,25 @@ func postProcessOptions(opts *Options) {
 	// Extend the default key map
 	keymap := defaultKeymap()
 	for key, actions := range opts.Keymap {
-		var lastChangePreviewWindow *action
+		reordered := []*action{}
 		for _, act := range actions {
 			switch act.t {
 			case actToggleSort:
 				// To display "+S"/"-S" on info line
 				opts.ToggleSort = true
-			case actChangePreviewWindow:
+			case actTogglePreview, actShowPreview, actHidePreview, actChangePreviewWindow:
-				lastChangePreviewWindow = act
+				reordered = append(reordered, act)
 			}
 		}
 
-		// Re-organize actions so that we only keep the last change-preview-window
+		// Re-organize actions so that we put actions that change the preview window first in the list.
-		// and it comes first in the list.
 		//  *  change-preview-window(up,+10)+preview(sleep 3; cat {})+change-preview-window(up,+20)
-		//  -> change-preview-window(up,+20)+preview(sleep 3; cat {})
+		//  -> change-preview-window(up,+10)+change-preview-window(up,+20)+preview(sleep 3; cat {})
-		if lastChangePreviewWindow != nil {
+		if len(reordered) > 0 {
-			reordered := []*action{lastChangePreviewWindow}
 			for _, act := range actions {
-				if act.t != actChangePreviewWindow {
+				switch act.t {
+				case actTogglePreview, actShowPreview, actHidePreview, actChangePreviewWindow:
+				default:
 					reordered = append(reordered, act)
 				}
 			}

src/terminal.go

@@ -3523,6 +3523,9 @@ func (t *Terminal) Loop() {
 
 				// Split window options
 				tokens := strings.Split(a.a, "|")
+				if len(tokens[0]) > 0 && t.initialPreviewOpts.hidden {
+					t.previewOpts.hidden = false
+				}
 				parsePreviewWindow(&t.previewOpts, tokens[0])
 				if len(tokens) > 1 {
 					a.a = strings.Join(append(tokens[1:], tokens[0]), "|")

test/test_go.rb

@@ -2493,6 +2493,39 @@ class TestGoFZF < TestBase
     end
   end
 
+  def test_change_preview_window_rotate_hidden
+    tmux.send_keys "seq 100 | #{FZF} --preview-window hidden --preview 'echo =={}==' --bind '" \
+      "a:change-preview-window(nohidden||down,1|)'", :Enter
+    tmux.until { |lines| assert_equal 100, lines.match_count }
+    tmux.until { |lines| refute_includes lines[1], '==1==' }
+    tmux.send_keys 'a'
+    tmux.until { |lines| assert_includes lines[1], '==1==' }
+    tmux.send_keys 'a'
+    tmux.until { |lines| refute_includes lines[1], '==1==' }
+    tmux.send_keys 'a'
+    tmux.until { |lines| assert_includes lines[-2], '==1==' }
+    tmux.send_keys 'a'
+    tmux.until { |lines| refute_includes lines[-2], '==1==' }
+    tmux.send_keys 'a'
+    tmux.until { |lines| assert_includes lines[1], '==1==' }
+  end
+
+  def test_change_preview_window_rotate_hidden_down
+    tmux.send_keys "seq 100 | #{FZF} --bind '?:change-preview-window:up||down|' --preview 'echo =={}==' --preview-window hidden,down,1", :Enter
+    tmux.until { |lines| assert_equal 100, lines.match_count }
+    tmux.until { |lines| refute_includes lines[1], '==1==' }
+    tmux.send_keys '?'
+    tmux.until { |lines| assert_includes lines[1], '==1==' }
+    tmux.send_keys '?'
+    tmux.until { |lines| refute_includes lines[1], '==1==' }
+    tmux.send_keys '?'
+    tmux.until { |lines| assert_includes lines[-2], '==1==' }
+    tmux.send_keys '?'
+    tmux.until { |lines| refute_includes lines[-2], '==1==' }
+    tmux.send_keys '?'
+    tmux.until { |lines| assert_includes lines[1], '==1==' }
+  end
+
   def test_ellipsis
     tmux.send_keys 'seq 1000 | tr "\n" , | fzf --ellipsis=SNIPSNIP -e -q500', :Enter
     tmux.until { |lines| assert_equal 1, lines.match_count }