Ensure that command-prompt is dismissed after a command creates a new screen

Fixes #1803

Running a command that created a new screen would previously result in a screen
order that looked like this, due to how `Screen::Hide` works:

- DF screen
  - `command-prompt` screen (dismissed)
    - New screen

The `command-prompt` screen remained on the stack until the new screen was
dismissed, so it would intercept viewscreen vmethod calls intended for the
DF screen.

This change adds a new behavior to `Screen::Hide` that results in this screen
order after running a command:

- DF screen
  - New screen
    - `command-prompt` screen (dismissed) - DF removes this screen immediately

docs/changelog.txt

@@ -33,6 +33,9 @@ changelog.txt uses a syntax similar to RST, with a few special sequences:
 
 # Future
 
+## Fixes
+- `command-prompt`: fixed issues where overlays created by running certain commands (e.g. `gui/liquids`, `gui/teleport`) would not update the parent screen correctly
+
 ## Documentation
 - Added more client library implementations to the `remote interface docs <remote-client-libs>`
 

library/include/modules/Screen.h

@@ -308,12 +308,15 @@ namespace DFHack
 
         //! Temporary hide a screen until destructor is called
         struct DFHACK_EXPORT Hide {
-            Hide(df::viewscreen* screen);
+            Hide(df::viewscreen* screen, int flags = 0);
             ~Hide();
+
+            static const int RESTORE_AT_TOP = 0x1;
         private:
             void extract(df::viewscreen*);
             void merge(df::viewscreen*);
-            df::viewscreen* screen_;
+            df::viewscreen* screen;
+            int flags;
         };
     }
 

library/modules/Screen.cpp

@@ -378,16 +378,16 @@ bool Screen::hasActiveScreens(Plugin *plugin)
 
 namespace DFHack { namespace Screen {
 
-Hide::Hide(df::viewscreen* screen) :
-    screen_{screen}
+Hide::Hide(df::viewscreen* screen, int flags) :
+    screen{screen}, flags{flags}
 {
-    extract(screen_);
+    extract(screen);
 }
 
 Hide::~Hide()
 {
-    if (screen_)
-        merge(screen_);
+    if (screen)
+        merge(screen);
 }
 
 void Hide::extract(df::viewscreen* a)
@@ -402,6 +402,13 @@ void Hide::extract(df::viewscreen* a)
 
 void Hide::merge(df::viewscreen* a)
 {
+    if (flags & RESTORE_AT_TOP) {
+        a->parent = NULL;
+        a->child = NULL;
+        Screen::show(std::unique_ptr<df::viewscreen>(a));
+        return;
+    }
+
     df::viewscreen* ap = a->parent;
     df::viewscreen* ac = a->parent->child;
 

plugins/command-prompt.cpp

@@ -201,7 +201,7 @@ void viewscreen_commandpromptst::submit()
     submitted = true;
     prompt_ostream out(this);
     {
-        Screen::Hide hide_guard(this);
+        Screen::Hide hide_guard(this, Screen::Hide::RESTORE_AT_TOP);
         Core::getInstance().runCommand(out, get_entry());
     }
     if(out.empty() && responses.empty())