From cca3794dd0f51038c081874abf55b37236810ff4 Mon Sep 17 00:00:00 2001
From: Rangi <sylvie.oukaour+rangi42@gmail.com>
Date: Mon, 6 Oct 2025 17:03:51 -0400
Subject: [PATCH] Mention libpng in its internal warning and error messages

---
 src/gfx/png.cpp       | 16 ++++++++++------
 src/gfx/reverse.cpp   |  8 ++++----
 test/gfx/damaged1.err |  2 +-
 test/gfx/damaged2.err |  2 +-
 test/gfx/damaged9.err |  2 +-
 5 files changed, 17 insertions(+), 13 deletions(-)

diff --git a/src/gfx/png.cpp b/src/gfx/png.cpp
index 8051fbd0..b9b8e815 100644
--- a/src/gfx/png.cpp
+++ b/src/gfx/png.cpp
@@ -31,15 +31,19 @@ struct Input {
 
 [[noreturn]]
 static void handleError(png_structp png, char const *msg) {
-	Input const &input = *reinterpret_cast<Input *>(png_get_error_ptr(png));
-
-	fatal("Error reading PNG image (\"%s\"): %s", input.filename, msg);
+	fatal(
+	    "libpng error while reading PNG image (\"%s\"): %s",
+	    reinterpret_cast<Input *>(png_get_error_ptr(png))->filename,
+	    msg
+	);
 }
 
 static void handleWarning(png_structp png, char const *msg) {
-	Input const &input = *reinterpret_cast<Input *>(png_get_error_ptr(png));
-
-	warnx("In PNG image (\"%s\"): %s", input.filename, msg);
+	warnx(
+	    "libpng found while reading PNG image (\"%s\"): %s",
+	    reinterpret_cast<Input *>(png_get_error_ptr(png))->filename,
+	    msg
+	);
 }
 
 static void readData(png_structp png, png_bytep data, size_t length) {
diff --git a/src/gfx/reverse.cpp b/src/gfx/reverse.cpp
index 21489eef..dffbb3cb 100644
--- a/src/gfx/reverse.cpp
+++ b/src/gfx/reverse.cpp
@@ -61,16 +61,16 @@ static std::vector<uint8_t> readInto(std::string const &path) {
 [[noreturn]]
 static void pngError(png_structp png, char const *msg) {
 	fatal(
-	    "Error writing reversed image (\"%s\"): %s",
-	    static_cast<char const *>(png_get_error_ptr(png)),
+	    "libpng error while writing reversed image (\"%s\"): %s",
+	    reinterpret_cast<char const *>(png_get_error_ptr(png)),
 	    msg
 	);
 }
 
 static void pngWarning(png_structp png, char const *msg) {
 	warnx(
-	    "While writing reversed image (\"%s\"): %s",
-	    static_cast<char const *>(png_get_error_ptr(png)),
+	    "libpng found while writing reversed image (\"%s\"): %s",
+	    reinterpret_cast<char const *>(png_get_error_ptr(png)),
 	    msg
 	);
 }
diff --git a/test/gfx/damaged1.err b/test/gfx/damaged1.err
index 4cf84370..68b8e494 100644
--- a/test/gfx/damaged1.err
+++ b/test/gfx/damaged1.err
@@ -1,2 +1,2 @@
-FATAL: Error reading PNG image ("damaged1.png"): IDAT: invalid code -- missing end-of-block
+FATAL: libpng error while reading PNG image ("damaged1.png"): IDAT: invalid code -- missing end-of-block
 Conversion aborted after 1 error
diff --git a/test/gfx/damaged2.err b/test/gfx/damaged2.err
index 5cfd98ad..78a5f7ca 100644
--- a/test/gfx/damaged2.err
+++ b/test/gfx/damaged2.err
@@ -1,2 +1,2 @@
-FATAL: Error reading PNG image ("damaged2.png"): IDAT: invalid code -- missing end-of-block
+FATAL: libpng error while reading PNG image ("damaged2.png"): IDAT: invalid code -- missing end-of-block
 Conversion aborted after 1 error
diff --git a/test/gfx/damaged9.err b/test/gfx/damaged9.err
index 51ffde74..44c93f51 100644
--- a/test/gfx/damaged9.err
+++ b/test/gfx/damaged9.err
@@ -1,2 +1,2 @@
-FATAL: Error reading PNG image ("damaged9.png"): IDAT: invalid code -- missing end-of-block
+FATAL: libpng error while reading PNG image ("damaged9.png"): IDAT: invalid code -- missing end-of-block
 Conversion aborted after 1 error