XSizeHints is made of int

[rikigigi]

The code wrongly assumes that XSizeHints contains unsigned int only, while this is not the case, leading to crashes if negative ints are found there
the crashes are like

blackbox: Window.cc:303: bt::Rect constrain(const bt::Rect&, const bt::EWMH::Strut&, const WMNormalHints&, Corner): Assertion `dw >= base_width && dh >= base_height' failed.
zsh: IOT instruction (core dumped)  blackbox

at the moment the patch

diff --git a/src/Window.cc b/src/Window.cc
index 71db507..4cebe3b 100644
--- a/src/Window.cc
+++ b/src/Window.cc
@@ -280,12 +280,12 @@ static bt::Rect constrain(const bt::Rect &rect,
               rect.right() - static_cast<signed>(margin.right),
               rect.bottom() - static_cast<signed>(margin.bottom));
 
-  unsigned int dw = r.width(), dh = r.height();
+  int dw = r.width(), dh = r.height();
 
-  const unsigned int base_width = (wmnormal.base_width
+  const int base_width = (wmnormal.base_width>0
                                    ? wmnormal.base_width
                                    : wmnormal.min_width),
-                    base_height = (wmnormal.base_height
+                    base_height = (wmnormal.base_height>0
                                    ? wmnormal.base_height
                                    : wmnormal.min_height);
 
@@ -299,6 +299,10 @@ static bt::Rect constrain(const bt::Rect &rect,
     dw = wmnormal.max_width;
   if (dh > wmnormal.max_height)
     dh = wmnormal.max_height;
+#ifdef    DEBUG
+    fprintf(stderr, "(dw, dh) = (%i, %i)\nbw=%i bh=%i\nbase_width\tmin_width\tbase_height\tmin_height\n %i\t%i\t%i\t%i\n",
+            dw, dh, base_width, base_height,wmnormal.base_width, wmnormal.min_width, wmnormal.base_height, wmnormal.min_height);
+#endif // DEBUG
 
   assert(dw >= base_width && dh >= base_height);

is the fastest possible correction in the case

(dw, dh) = (640, 480)
bw=-1 bh=-1
base_width	min_width	base_height	min_height
 -1	1	-1	1

but the correct solution is to change the data type from unsigned int to int everywhere it is needed

[bbidulock]

How can there be a negative width?

[rikigigi]

that's a good question, but if the XSizeHints is not unsigned, the code must be able to deal with negative integers and decide what to do (discard it).
My particular case was the Zoom client 5.11.10 (4400) + gentoo linux

[bbidulock]

The X server will not return a negative width, so that is not an issue.