Ensure display buffer is up-to-date before view commands

While not strictly necessary, the buffer timestamp stored inside
the display buffer being out of date may lead to scrolling on next
display update, this scrolling is undesirable after a view command,
in order to disable it we need that timestamp to be updated and
doing a full display buffer update is the simplest way to achieve
that.

Fixes #5364

Author: mawww

src/normal.cc

@@ -385,6 +385,7 @@ void view_commands(Context& context, NormalParams params)
 
         const BufferCoord cursor = context.selections().main().cursor();
         Window& window = context.window();
+        window.update_display_buffer(context);
 
         const DisplayCoord scrolloff = context.options()["scrolloff"].get<DisplayCoord>();
         const LineCount line_offset{std::min((window.dimensions().line - 1) / 2, scrolloff.line)};

test/regression/5364-exec-and-view-commands-anomalous-interaction/cmd

@@ -0,0 +1 @@
+<c-l>:exec<space>ggi<lt>ret<gt><lt>esc<gt>/^c$<lt>ret<gt>vt<ret>

test/regression/5364-exec-and-view-commands-anomalous-interaction/in

@@ -0,0 +1,5 @@
+a
+b
+c
+d
+e

test/regression/5364-exec-and-view-commands-anomalous-interaction/script

@@ -0,0 +1,2 @@
+ui_out -until '{ "jsonrpc": "2.0", "method": "refresh", "params": [true] }'
+ui_out '{ "jsonrpc": "2.0", "method": "draw", "params": [[[{ "face": { "fg": "black", "bg": "white", "underline": "default", "attributes": [] }, "contents": "c" }, { "face": { "fg": "default", "bg": "default", "underline": "default", "attributes": [] }, "contents": "\u000a" }], [{ "face": { "fg": "default", "bg": "default", "underline": "default", "attributes": [] }, "contents": "d\u000a" }], [{ "face": { "fg": "default", "bg": "default", "underline": "default", "attributes": [] }, "contents": "e\u000a" }]], { "fg": "default", "bg": "default", "underline": "default", "attributes": [] }, { "fg": "blue", "bg": "default", "underline": "default", "attributes": [] }] }'