From 760c816161fdf75dca4427da55021f314f407965 Mon Sep 17 00:00:00 2001
From: Justin Israel <justinisrael@gmail.com>
Date: Thu, 4 Apr 2024 09:07:59 +1300
Subject: [PATCH] Check last error after query to FontMetrics to prevent panic
 (fixes #309)

---
 imagick/magick_wand.go      |  6 ++++++
 imagick/magick_wand_test.go | 18 ++++++++++++++++++
 2 files changed, 24 insertions(+)

diff --git a/imagick/magick_wand.go b/imagick/magick_wand.go
index 68cc8b3..3bb0d16 100644
--- a/imagick/magick_wand.go
+++ b/imagick/magick_wand.go
@@ -129,6 +129,9 @@ func (mw *MagickWand) QueryFontMetrics(dw *DrawingWand, textLine string) *FontMe
 	cstext := C.CString(textLine)
 	defer C.free(unsafe.Pointer(cstext))
 	cdoubles := C.MagickQueryFontMetrics(mw.mw, dw.dw, cstext)
+	if err := mw.GetLastError(); err != nil {
+		return nil
+	}
 	runtime.KeepAlive(mw)
 	runtime.KeepAlive(dw)
 	defer relinquishMemory(unsafe.Pointer(cdoubles))
@@ -141,6 +144,9 @@ func (mw *MagickWand) QueryMultilineFontMetrics(dw *DrawingWand, textParagraph s
 	cstext := C.CString(textParagraph)
 	defer C.free(unsafe.Pointer(cstext))
 	cdoubles := C.MagickQueryMultilineFontMetrics(mw.mw, dw.dw, cstext)
+	if err := mw.GetLastError(); err != nil {
+		return nil
+	}
 	runtime.KeepAlive(mw)
 	runtime.KeepAlive(dw)
 	defer relinquishMemory(unsafe.Pointer(cdoubles))
diff --git a/imagick/magick_wand_test.go b/imagick/magick_wand_test.go
index 13eadb0..1e80846 100644
--- a/imagick/magick_wand_test.go
+++ b/imagick/magick_wand_test.go
@@ -101,6 +101,24 @@ func TestQueryFonts(t *testing.T) {
 	}
 }
 
+func TestQueryFontMetrics(t *testing.T) {
+	Initialize()
+	defer func(t *testing.T) {
+		checkGC(t)
+	}(t)
+	defer Terminate()
+
+	mw := NewMagickWand()
+	// Create an empty wand. Don't ready anything.
+	//if err := mw.ReadImage("xc:black"); err != nil {
+	//	panic(err)
+	//}
+	fonts := mw.QueryFontMetrics(NewDrawingWand(), "")
+	if fonts != nil {
+		t.Fatal("Expected a nil FontMetrics when passing a bad MagickWand")
+	}
+}
+
 func TestQueryFormats(t *testing.T) {
 	Initialize()
 	defer func(t *testing.T) {