Preserve wrap state across change-preview-window

toggle-preview-wrap (and -wrap-word) modifies t.activePreviewOpts.wrap,
but change-preview-window resets t.previewOpts to t.initialPreviewOpts,
discarding the user's toggle. Carry wrap and wrapWord over so toggles
survive a layout change. Explicit wrap / nowrap tokens in the new spec
still win, so cycling and the empty-token reset are unaffected.

Close #4791

CHANGELOG.md

@@ -1,6 +1,11 @@
 CHANGELOG
 =========
 
+0.73.0
+------
+- Bug fixes
+    - `change-preview-window` no longer resets `wrap` / `wrap-word` state set via `toggle-preview-wrap` / `toggle-preview-wrap-word`. Layout fields still snap to the preset, so cycling and the empty-token reset behave as before. The new spec can still override by including `wrap` or `nowrap` explicitly. (#4791)
+
 0.72.0
 ------
 _Release highlights: https://junegunn.github.io/fzf/releases/0.72.0/_

src/terminal.go

@@ -7819,6 +7819,11 @@ func (t *Terminal) Loop() error {
 				t.previewOpts = t.initialPreviewOpts
 				t.previewOpts.command = currentPreviewOpts.command
 
+				// Carry over toggle-driven state so toggle-preview-wrap survives
+				// a change-preview-window. Tokens below can still override.
+				t.previewOpts.wrap = currentPreviewOpts.wrap
+				t.previewOpts.wrapWord = currentPreviewOpts.wrapWord
+
 				// Split window options
 				tokens := strings.Split(a.a, "|")
 				if len(tokens[0]) > 0 && t.initialPreviewOpts.hidden {

test/test_preview.rb

@@ -383,6 +383,49 @@ class TestPreview < TestInteractive
     end
   end
 
+  def test_change_preview_window_preserves_wrap_toggle
+    # https://github.com/junegunn/fzf/issues/4791
+    tmux.send_keys "#{FZF} --preview 'for i in $(seq $FZF_PREVIEW_COLUMNS); do echo -n .; done; echo -n .; echo wrapped; echo 2nd line' " \
+                   "--preview-window 'right,nowrap,border-rounded' " \
+                   '--bind ctrl-w:toggle-preview-wrap ' \
+                   '--bind ctrl-r:change-preview-window:border-bold', :Enter
+    sleep 2
+    # Initial: nowrap, rounded border. The long line is truncated; "wrapped" is hidden.
+    tmux.until do |lines|
+      assert_includes lines[2], '2nd line'
+      assert(lines.any? { it.include?('╭') })
+    end
+    # Toggle wrap on.
+    tmux.send_keys 'C-w'
+    tmux.until do |lines|
+      assert_includes lines[2], 'wrapped'
+      assert_includes lines[3], '2nd line'
+    end
+    # change-preview-window swaps the border to bold; wrap state must persist.
+    tmux.send_keys 'C-r'
+    tmux.until do |lines|
+      assert(lines.any? { it.include?('┏') })  # border actually changed
+      refute(lines.any? { it.include?('╭') })
+      assert_includes lines[2], 'wrapped'      # wrap was preserved
+      assert_includes lines[3], '2nd line'
+    end
+  end
+
+  def test_change_preview_window_overrides_wrap_explicitly
+    # When the new spec sets wrap/nowrap explicitly, it should still win.
+    tmux.send_keys "#{FZF} --preview 'for i in $(seq $FZF_PREVIEW_COLUMNS); do echo -n .; done; echo -n .; echo wrapped; echo 2nd line' " \
+                   "--preview-window 'right,wrap' " \
+                   '--bind ctrl-r:change-preview-window:nowrap', :Enter
+    # Initial: wrap is on.
+    tmux.until do |lines|
+      assert_includes lines[2], 'wrapped'
+      assert_includes lines[3], '2nd line'
+    end
+    # Explicit nowrap in the spec must override the (initially wrapped) state.
+    tmux.send_keys 'C-r'
+    tmux.until { |lines| assert_includes lines[2], '2nd line' }
+  end
+
   def test_preview_follow_wrap
     tmux.send_keys "seq 1 | #{FZF} --preview 'seq 1000' --preview-window right,2,follow,wrap", :Enter
     tmux.until { |lines| assert_equal 1, lines.match_count }