Cursor style not handled correctly

[antoniy]

My cursor changes style from pipe to rectangle in ZSH shell when use vim mode but also in vim when switching from Normal and Insert modes. The cursor changes styles when I use ssh but in a mosh session, I see only the pipe-style cursor and it never changes.

Is there a way to fix that behavior?

I'm using the latest git version build on the server and on the client.
Server - archlinux: mosh 1.3.2 [build mosh-1.3.2-86-g0cc492d]
Client - macosx: mosh 1.3.2 [build mosh-1.3.2-86-g0cc492d]

[matheusfillipe]

I have the exact same issue with arch server and ubuntu client.

[mqzabin]

I have the same issue. My brain use the cursor shape as a primary normal/insert mode detection. It's painfull.

[disrupted]

same here using mosh-server and client compiled from latest master

[kovasap]

Same here!

[damnskippy]

Long standing known open issue: #352
Probably the most sorely lacking or user impacting missing functionality when using terminal IMHO in an otherwise wonderfully life saving app.

[waltarix]

Here is a patch for this issue. (based on 378dfa6)
Hope this helps.

diff --git b/src/terminal/terminaldisplay.cc a/src/terminal/terminaldisplay.cc
index e7595c2..9034072 100644
--- b/src/terminal/terminaldisplay.cc
+++ a/src/terminal/terminaldisplay.cc
@@ -154,6 +154,12 @@ std::string Display::new_frame( bool initialized, const Framebuffer &last, const
     frame.append( "\033[?25l" );
   }
 
+  /* is cursor style initialized? */
+  if ( !initialized ) {
+    frame.cursor_style = Terminal::CursorStyle::BLINKING_BLOCK;
+    frame.append( "\033[0 q" );
+  }
+
   int frame_y = 0;
   Framebuffer::row_pointer blank_row;
   Framebuffer::rows_type rows( frame.last_frame.get_rows() );
@@ -286,6 +292,14 @@ std::string Display::new_frame( bool initialized, const Framebuffer &last, const
     }
   }
 
+  /* has cursor style changed? */
+  if ( (!initialized)
+       || (f.ds.cursor_style != frame.cursor_style) ) {
+    char cursor_style_sequence_buf[6];
+    snprintf( cursor_style_sequence_buf, sizeof cursor_style_sequence_buf, "\033[%d q", f.ds.cursor_style );
+    frame.append( cursor_style_sequence_buf );
+  }
+
   /* have renditions changed? */
   frame.update_rendition( f.ds.get_renditions(), !initialized );
 
@@ -483,6 +497,7 @@ bool Display::put_row( bool initialized, FrameState &frame, const Framebuffer &f
 FrameState::FrameState( const Framebuffer &s_last )
       : str(), cursor_x(0), cursor_y(0), current_rendition( 0 ),
 	cursor_visible( s_last.ds.cursor_visible ),
+	cursor_style( s_last.ds.cursor_style ),
 	last_frame( s_last )
 {
   /* Preallocate for better performance.  Make a guess-- doesn't matter for correctness */
diff --git b/src/terminal/terminaldisplay.h a/src/terminal/terminaldisplay.h
index 81009b0..0d6335d 100644
--- b/src/terminal/terminaldisplay.h
+++ a/src/terminal/terminaldisplay.h
@@ -44,6 +44,7 @@ namespace Terminal {
     int cursor_x, cursor_y;
     Renditions current_rendition;
     bool cursor_visible;
+    int cursor_style;
 
     const Framebuffer &last_frame;
 
diff --git b/src/terminal/terminalframebuffer.cc a/src/terminal/terminalframebuffer.cc
index 2751f3b..7b7d076 100644
--- b/src/terminal/terminalframebuffer.cc
+++ a/src/terminal/terminalframebuffer.cc
@@ -69,6 +69,7 @@ DrawState::DrawState( int s_width, int s_height )
     combining_char_col( 0 ), combining_char_row( 0 ), default_tabs( true ), tabs( s_width ),
     scrolling_region_top_row( 0 ), scrolling_region_bottom_row( height - 1 ),
     renditions( 0 ), save(),
+    cursor_style( Terminal::CursorStyle::BLINKING_BLOCK ),
     next_print_will_wrap( false ), origin_mode( false ), auto_wrap_mode( true ),
     insert_mode( false ), cursor_visible( true ), reverse_video( false ),
     bracketed_paste( false ), mouse_reporting_mode( MOUSE_REPORTING_NONE ), mouse_focus_event( false ),
@@ -392,6 +393,7 @@ void Framebuffer::soft_reset( void )
   ds.insert_mode = false;
   ds.origin_mode = false;
   ds.cursor_visible = true; /* per xterm and gnome-terminal */
+  ds.cursor_style = Terminal::CursorStyle::BLINKING_BLOCK;
   ds.application_mode_cursor_keys = false;
   ds.set_scrolling_region( 0, ds.get_height() - 1 );
   ds.add_rendition( 0 );
diff --git b/src/terminal/terminalframebuffer.h a/src/terminal/terminalframebuffer.h
index de93869..4c2345b 100644
--- b/src/terminal/terminalframebuffer.h
+++ a/src/terminal/terminalframebuffer.h
@@ -51,6 +51,16 @@ namespace Terminal {
   using shared::make_shared;
   typedef uint32_t color_type;
 
+  enum CursorStyle {
+    BLINKING_BLOCK = 0,
+    BLINKING_BLOCK_DEFAULT = 1,
+    STEADY_BLOCK = 2,
+    BLINKING_UNDERLINE = 3,
+    STEADY_UNDERLINE = 4,
+    BLINKING_BAR = 5,
+    STEADY_BAR = 6,
+  };
+
   class Renditions {
   public:
     typedef enum { bold, faint, italic, underlined, blink, inverse, invisible, SIZE } attribute_type;
@@ -275,6 +285,8 @@ namespace Terminal {
     SavedCursor save;
 
   public:
+    int cursor_style;
+
     bool next_print_will_wrap;
     bool origin_mode;
     bool auto_wrap_mode;
@@ -351,6 +363,7 @@ namespace Terminal {
       return ( width == x.width ) && ( height == x.height ) && ( cursor_col == x.cursor_col )
 	&& ( cursor_row == x.cursor_row ) && ( cursor_visible == x.cursor_visible ) &&
 	( reverse_video == x.reverse_video ) && ( renditions == x.renditions ) &&
+	( cursor_style == x.cursor_style ) &&
   ( bracketed_paste == x.bracketed_paste ) && ( mouse_reporting_mode == x.mouse_reporting_mode ) &&
   ( mouse_focus_event == x.mouse_focus_event ) && ( mouse_alternate_scroll == x.mouse_alternate_scroll) &&
   ( mouse_encoding_mode == x.mouse_encoding_mode );
diff --git b/src/terminal/terminalfunctions.cc a/src/terminal/terminalfunctions.cc
index ca141dd..7cf6e58 100644
--- b/src/terminal/terminalfunctions.cc
+++ a/src/terminal/terminalfunctions.cc
@@ -50,6 +50,26 @@ static void clearline( Framebuffer *fb, int row, int start, int end )
   }
 }
 
+/* cursor style */
+static void CSI_DECSCUSR( Framebuffer *fb, Dispatcher *dispatch ) {
+  int style = dispatch->getparam( 0, 0 );
+  switch ( style ) {
+  case 0:
+  case 1:
+  case 2:
+  case 3:
+  case 4:
+  case 5:
+  case 6:
+    fb->ds.cursor_style = style;
+    break;
+  default:
+    break;
+  }
+}
+
+static Function func_CSI_DECSCUSR( CSI, " q", CSI_DECSCUSR );
+
 /* erase in line */
 static void CSI_EL( Framebuffer *fb, Dispatcher *dispatch )
 {

[disrupted]

@waltarix really cool! have you already created a PR for it?

[waltarix]

No, I haven't, because it's just a quick fix.
However, anyone is free to use this patch, so if someone wants to make a PR, that would be great.

[matheusfillipe]

@waltarix I tested your patch and it fixes the issue on my case. I took the freedom to submit a PR with your changes now.

[waltarix]

That's nice. Thanks for your help.

[jasonjurotich]

Any news on whether they are going to add this. We still can't see the cursor change using mosh...

[Ingvix]

@waltarix's patch doesn't seem to work for me on st. I only see a blinking block. Any thoughts?

[achernya]

Marking this as a duplicate of #352 which covers more cursor style issues.