From 297abdbb06f8dcc2320a87954e1b3165ec2489c5 Mon Sep 17 00:00:00 2001
From: brandon s allbery kf8nh <allbery.b@gmail.com>
Date: Fri, 7 Feb 2025 10:51:02 -0500
Subject: [PATCH 1/3] check for font open errors

This may not have been done because `throwIfNull` can't be used
directly. A wrapper using `coerce` works, though. Prevents xmonad
from dumping core in `XMonad.Prompt.printPrompt` if an invalid
font is specified.
---
 Graphics/X11/Xft.hsc | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/Graphics/X11/Xft.hsc b/Graphics/X11/Xft.hsc
index c86918e..a13e54f 100644
--- a/Graphics/X11/Xft.hsc
+++ b/Graphics/X11/Xft.hsc
@@ -1,4 +1,5 @@
 {-# LANGUAGE ForeignFunctionInterface #-}
+{-# LANGUAGE FlexibleContexts #-}
 
 -----------------------------------------------------------------------------
 -- Module      :  Graphics.X11.Xft
@@ -58,6 +59,7 @@ import Codec.Binary.UTF8.String as UTF8
 import Control.Arrow ((&&&))
 import Control.Monad (void)
 import Data.Char (ord)
+import Data.Coerce (coerce, Coercible)
 import Data.Function (on)
 import Data.List (foldl')
 import Data.List.NonEmpty (NonEmpty)
@@ -68,6 +70,11 @@ import Foreign.C.Types
 
 #include <X11/Xft/Xft.h>
 
+-- I wonder how many times this has been reinvented...
+-- (upstream won't accept it because of the GHCisms, I suspect)
+throwIfNullXft :: Coercible a (Ptr b) => String -> IO a -> IO a
+throwIfNullXft fn op = fmap coerce $ throwIfNull fn (fmap coerce op)
+
 -----------------------
 -- Color Handling    --
 -----------------------
@@ -172,14 +179,15 @@ foreign import ccall "XftFontOpenName"
 xftFontOpen :: Display -> Screen -> String -> IO XftFont
 xftFontOpen dpy screen fontname =
     withCAString fontname $
-      \cfontname -> cXftFontOpen dpy (fi (screenNumberOfScreen screen)) cfontname
+      \cfontname -> throwIfNullXft "xftFontOpen" $ cXftFontOpen dpy (fi (screenNumberOfScreen screen)) cfontname
 
 foreign import ccall "XftFontOpenXlfd"
   cXftFontOpenXlfd :: Display -> CInt -> CString -> IO XftFont
 
 xftFontOpenXlfd :: Display -> Screen -> String -> IO XftFont
 xftFontOpenXlfd dpy screen fontname =
-    withCAString fontname $ \cfontname -> cXftFontOpenXlfd dpy (fi (screenNumberOfScreen screen)) cfontname
+    withCAString fontname $ \cfontname -> throwIfNullXft "xftFontOpenXlfd" $
+      cXftFontOpenXlfd dpy (fi (screenNumberOfScreen screen)) cfontname
 
 foreign import ccall "XftLockFace"
   xftLockFace :: XftFont -> IO ()                  -- FIXME XftLockFace returns FT_face not void

From b2fd64dec27f0f98a14489efc7a125413118aa72 Mon Sep 17 00:00:00 2001
From: brandon s allbery kf8nh <allbery.b@gmail.com>
Date: Fri, 7 Feb 2025 11:18:56 -0500
Subject: [PATCH 2/3] simplify

may also reduce runtime overhead
---
 Graphics/X11/Xft.hsc | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Graphics/X11/Xft.hsc b/Graphics/X11/Xft.hsc
index a13e54f..54443f4 100644
--- a/Graphics/X11/Xft.hsc
+++ b/Graphics/X11/Xft.hsc
@@ -73,7 +73,7 @@ import Foreign.C.Types
 -- I wonder how many times this has been reinvented...
 -- (upstream won't accept it because of the GHCisms, I suspect)
 throwIfNullXft :: Coercible a (Ptr b) => String -> IO a -> IO a
-throwIfNullXft fn op = fmap coerce $ throwIfNull fn (fmap coerce op)
+throwIfNullXft fn op = coerce $ throwIfNull fn (coerce op)
 
 -----------------------
 -- Color Handling    --

From f66994d679686f542336db7e143062725e7eac9f Mon Sep 17 00:00:00 2001
From: brandon s allbery kf8nh <allbery.b@gmail.com>
Date: Fri, 7 Feb 2025 12:18:45 -0500
Subject: [PATCH 3/3] bump version

Users will need to know that they need to check for exceptions.
---
 CHANGES.md    | 6 ++++++
 X11-xft.cabal | 2 +-
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/CHANGES.md b/CHANGES.md
index 346f2d7..1853998 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -1,5 +1,11 @@
 # Change Log / Release Notes
 
+## _unreleased_
+
+  * `xftOpenFont` and `xftOpenFontXlfd` now throw exceptions if opening a
+    font fails. (They used to return a null pointer, usually leading to
+    crashes.)
+
 ## 0.3.4 (2021-12-11)
 
   * Dropped support for GHC 7.10.
diff --git a/X11-xft.cabal b/X11-xft.cabal
index 622ad88..abf68ec 100644
--- a/X11-xft.cabal
+++ b/X11-xft.cabal
@@ -1,6 +1,6 @@
 cabal-version: 1.24
 name:          X11-xft
-version:       0.3.4
+version:       0.3.5
 license:       BSD3
 license-file:  LICENSE
 author:        Clemens Fruhwirth