Fix assert with window small enough so that no part of buffer is displayed

Fixes #2056

6 files changed, 25 insertions, 2 deletions

diff --git a/src/highlighters.cc b/src/highlighters.cc
index d1425f39..eafe8a4f 100644
--- a/src/highlighters.cc
+++ b/src/highlighters.cc
@@ -1064,7 +1064,7 @@ private:
             return;
 
         ColumnCount width = compute_digit_count(context.context) + m_separator.column_length();
-        setup.window_range.column -= width;
+        setup.window_range.column -= std::min(width, setup.window_range.column);
     }
 
     void fill_unique_ids(Vector<StringView>& unique_ids) const override
@@ -1347,7 +1347,7 @@ private:
             return;
         }
 
-        setup.window_range.column -= width;
+        setup.window_range.column -= std::min(width, setup.window_range.column);
     }
 
     String m_option_name;
diff --git a/src/window.cc b/src/window.cc
index a57e7426..43ee52db 100644
--- a/src/window.cc
+++ b/src/window.cc
@@ -190,6 +190,14 @@ void Window::set_dimensions(DisplayCoord dimensions)
     }
 }
 
+static void check_display_setup(const DisplaySetup& setup, const Window& window)
+{
+    kak_assert(setup.window_pos.line >= 0 and setup.window_pos.line < window.buffer().line_count());
+    kak_assert(setup.window_pos.column >= 0);
+    kak_assert(setup.window_range.column >= 0);
+    kak_assert(setup.window_range.line >= 0);
+}
+
 DisplaySetup Window::compute_display_setup(const Context& context) const
 {
     auto win_pos = m_position;
@@ -217,6 +225,7 @@ DisplaySetup Window::compute_display_setup(const Context& context) const
     };
     for (auto pass : { HighlightPass::Move, HighlightPass::Wrap })
         m_builtin_highlighters.compute_display_setup({context, pass, {}}, setup);
+    check_display_setup(setup, *this);
 
     // now ensure the cursor column is visible
     {
@@ -233,6 +242,7 @@ DisplaySetup Window::compute_display_setup(const Context& context) const
             setup.window_pos.column += overflow;
             setup.cursor_pos.column -= overflow;
         }
+        check_display_setup(setup, *this);
     }
 
     return setup;
diff --git a/test/regression/2056-assert-on-small-window/cmd b/test/regression/2056-assert-on-small-window/cmd
new file mode 100644
index 00000000..7f1441cd
--- /dev/null
+++ b/test/regression/2056-assert-on-small-window/cmd
@@ -0,0 +1 @@
+<c-l>
diff --git a/test/regression/2056-assert-on-small-window/in b/test/regression/2056-assert-on-small-window/in
new file mode 100644
index 00000000..f00c965d
--- /dev/null
+++ b/test/regression/2056-assert-on-small-window/in
@@ -0,0 +1,10 @@
+1
+2
+3
+4
+5
+6
+7
+8
+9
+10
diff --git a/test/regression/2056-assert-on-small-window/rc b/test/regression/2056-assert-on-small-window/rc
new file mode 100644
index 00000000..d2d73e00
--- /dev/null
+++ b/test/regression/2056-assert-on-small-window/rc
@@ -0,0 +1 @@
+add-highlighter window number_lines
diff --git a/test/regression/2056-assert-on-small-window/ui-in b/test/regression/2056-assert-on-small-window/ui-in
new file mode 100644
index 00000000..35c9d9a6
--- /dev/null
+++ b/test/regression/2056-assert-on-small-window/ui-in
@@ -0,0 +1 @@
+{ "jsonrpc": "2.0", "method": "resize", "params": [ 5, 2 ] }