Also handle overflown screens if editing pager search field

As mentioned in 04c913427 (Limit command line rendering to $LINES
lines, 2024-10-25) our rendering breaks when the command line overflows
the screen and we have a pager search field.

Let's also apply the overflow logic in this case.

Note that the search field still works, it's just not visible.

In future we should maybe show a small search field (~4 lines) in
this case (removing 4 screen lines worth of command line).  But again,
this is not really important.

src/pager.rs

@@ -71,7 +71,7 @@ const PAGER_UNDISCLOSED_MAX_ROWS: usize = 4;
 const PAGER_MIN_WIDTH: usize = 16;
 
 /// Minimum height to show completions
-const PAGER_MIN_HEIGHT: usize = 4;
+pub const PAGER_MIN_HEIGHT: usize = 4;
 
 /// The maximum number of columns of completion to attempt to fit onto the screen.
 const PAGER_MAX_COLS: usize = 6;

src/reader.rs

@@ -427,8 +427,8 @@ struct LayoutData {
     /// Position of the cursor in the command line.
     position: usize,
 
-    /// Whether the cursor is focused on the pager or not.
-    focused_on_pager: bool,
+    /// The cursor position in the pager search field.
+    pager_search_field_position: Option<usize>,
 
     /// Visual selection of the command line, or none if none.
     selection: Option<SelectionData>,
@@ -1386,6 +1386,7 @@ impl<'a> Reader<'a> {
         };
 
         let focused_on_pager = self.active_edit_line_tag() == EditableLineTag::SearchField;
+        let pager_search_field_position = focused_on_pager.then_some(self.pager.cursor_position());
         let last = &self.rendered_layout;
         check(self.force_exec_prompt_and_repaint, "forced")
             || check(self.command_line.text() != last.text, "text")
@@ -1394,8 +1395,11 @@ impl<'a> Reader<'a> {
                 "highlight",
             )
             || check(self.selection != last.selection, "selection")
-            || check(focused_on_pager != last.focused_on_pager, "focus")
             || check(self.command_line.position() != last.position, "position")
+            || check(
+                pager_search_field_position != last.pager_search_field_position,
+                "pager_search_field_position",
+            )
             || check(
                 self.history_search.search_range_if_active() != last.history_search_range,
                 "history search",
@@ -1431,13 +1435,10 @@ impl<'a> Reader<'a> {
         result.text = self.command_line.text().to_owned();
         result.colors = self.command_line.colors().to_vec();
         assert!(result.text.len() == result.colors.len());
-        result.position = if focused_on_pager {
-            self.pager.cursor_position()
-        } else {
-            self.command_line.position()
-        };
+        result.position = self.command_line.position();
+        result.pager_search_field_position =
+            focused_on_pager.then_some(self.pager.cursor_position());
         result.selection = self.selection;
-        result.focused_on_pager = focused_on_pager;
         result.history_search_range = self.history_search.search_range_if_active();
         result.autosuggestion = self.autosuggestion.text.clone();
         result.left_prompt_buff = self.left_prompt_buff.clone();
@@ -1516,10 +1517,10 @@ impl<'a> Reader<'a> {
             &colors,
             &indents,
             data.position,
+            data.pager_search_field_position,
             self.parser.vars(),
             pager,
             current_page_rendering,
-            data.focused_on_pager,
         );
     }
 }

src/screen.rs

@@ -7,7 +7,7 @@
 //! The current implementation is less smart than ncurses allows and can not for example move blocks
 //! of text around to handle text insertion.
 
-use crate::pager::{PageRendering, Pager};
+use crate::pager::{PageRendering, Pager, PAGER_MIN_HEIGHT};
 use std::cell::RefCell;
 use std::collections::LinkedList;
 use std::ffi::{CStr, CString};
@@ -237,7 +237,6 @@ impl Screen {
     /// of the command line \param colors the colors to use for the commanad line \param indent the
     /// indent to use for the command line \param cursor_pos where the cursor is \param pager the
     /// pager to render below the command line \param page_rendering to cache the current pager view
-    /// \param cursor_is_within_pager whether the position is within the pager line (first line)
     pub fn write(
         &mut self,
         left_prompt: &wstr,
@@ -247,10 +246,10 @@ impl Screen {
         colors: &[HighlightSpec],
         indent: &[i32],
         cursor_pos: usize,
+        pager_search_field_position: Option<usize>,
         vars: &dyn Environment,
         pager: &mut Pager,
         page_rendering: &mut PageRendering,
-        cursor_is_within_pager: bool,
     ) {
         let curr_termsize = termsize_last();
         let screen_width = curr_termsize.width;
@@ -337,7 +336,7 @@ impl Screen {
         let mut i = 0;
         loop {
             // Grab the current cursor's x,y position if this character matches the cursor's offset.
-            if !cursor_is_within_pager && i == cursor_pos {
+            if i == cursor_pos {
                 cursor_arr = Some(ScrolledCursor {
                     cursor: self.desired.cursor,
                     scroll_amount: (self.desired.line_count()
@@ -379,39 +378,44 @@ impl Screen {
             }
             i += 1;
         }
-        cursor_arr.as_mut().map(
-            |ScrolledCursor {
-                 ref mut cursor,
-                 scroll_amount,
-             }| {
-                if *scroll_amount != 0 {
-                    self.desired.line_datas = self.desired.line_datas.split_off(*scroll_amount);
-                    cursor.y -= *scroll_amount;
-                }
-            },
-        );
 
         let full_line_count = self.desired.cursor.y + 1;
+        let pager_available_height = std::cmp::max(
+            1,
+            curr_termsize
+                .height
+                .saturating_sub_unsigned(full_line_count),
+        );
 
         // Now that we've output everything, set the cursor to the position that we saved in the loop
         // above.
-        self.desired.cursor = cursor_arr.as_ref().map(|sc| sc.cursor).unwrap_or_default();
-
-        if cursor_is_within_pager {
-            self.desired.cursor.x = cursor_pos;
-            self.desired.cursor.y = self.desired.line_count();
-        }
+        self.desired.cursor = match pager_search_field_position {
+            Some(pager_cursor_pos)
+                if pager_available_height >= isize::try_from(PAGER_MIN_HEIGHT).unwrap() =>
+            {
+                Cursor {
+                    x: pager_cursor_pos,
+                    y: self.desired.line_count(),
+                }
+            }
+            _ => {
+                let ScrolledCursor {
+                    mut cursor,
+                    scroll_amount,
+                } = cursor_arr.unwrap();
+                if scroll_amount != 0 {
+                    self.desired.line_datas = self.desired.line_datas.split_off(scroll_amount);
+                    cursor.y -= scroll_amount;
+                }
+                cursor
+            }
+        };
 
         // Re-render our completions page if necessary. Limit the term size of the pager to the true
         // term size, minus the number of lines consumed by our string.
         pager.set_term_size(&Termsize::new(
             std::cmp::max(1, curr_termsize.width),
-            std::cmp::max(
-                1,
-                curr_termsize
-                    .height
-                    .saturating_sub_unsigned(full_line_count),
-            ),
+            pager_available_height,
         ));
 
         pager.update_rendering(page_rendering);