Implement -c #none (#1301)

Also adds a test case for round-tripping `-r` with `-c #none`.

test/gfx/none_comma_ommission.err

@@ -0,0 +1,4 @@
+error: Unexpected character, expected ',', ';', or end of argument
+In inline palette spec: #000,#none#fff
+                                  ^
+Conversion aborted after 1 error

test/gfx/none_comma_ommission.flags

@@ -0,0 +1 @@
+-c #000,#none#fff

test/gfx/rgbgfx_test.cpp

@@ -281,6 +281,21 @@ public:
 };
 
 static char *execProg(char const *name, char * const *argv) {
+	auto formatArgv = [&argv] {
+		// This is `static` so that the returned `buf.c_str()` will live long enough
+		// for `fatal()` to use it below.
+		static std::string buf;
+
+		buf.clear();
+		for (char * const *arg = argv; *arg != nullptr; ++arg) {
+			buf.push_back('"');
+			buf.append(*arg);
+			buf.append("\", ");
+		}
+		buf.resize(buf.length() - 2);
+		return buf.c_str();
+	};
+
 #if !defined(_MSC_VER) && !defined(__MINGW32__)
 	pid_t pid;
 	int err = posix_spawn(&pid, argv[0], nullptr, nullptr, argv, nullptr);
@@ -293,10 +308,10 @@ static char *execProg(char const *name, char * const *argv) {
 		fatal("Error waiting for %s: %s", name, strerror(errno));
 	} else if (info.si_code != CLD_EXITED) {
 		assert(info.si_code == CLD_KILLED || info.si_code == CLD_DUMPED);
-		fatal("%s was terminated by signal %s%s", name, strsignal(info.si_status),
-		      info.si_code == CLD_DUMPED ? " (core dumped)" : "");
+		fatal("%s was terminated by signal %s%s\n\tThe command was: [%s]", name, strsignal(info.si_status),
+		      info.si_code == CLD_DUMPED ? " (core dumped)" : "", formatArgv());
 	} else if (info.si_status != 0) {
-		fatal("%s returned with status %d", name, info.si_status);
+		fatal("%s returned with status %d\n\tThe command was: [%s]", name, info.si_status, formatArgv());
 	}
 
 #else // defined(_MSC_VER) || defined(__MINGW32__)
@@ -362,7 +377,7 @@ static char *execProg(char const *name, char * const *argv) {
 	CloseHandle(child.hThread);
 
 	if (status != 0) {
-		fatal("%s returned with status %ld", name, status);
+		fatal("%s returned with status %ld\n\tThe command was: [%s]", name, status, formatArgv());
 	}
 #endif
 

test/gfx/test.sh

@@ -39,8 +39,15 @@ for f in *.bin; do
 	done
 done
 
+# Test round-tripping '-r' with '-c #none'
+reverse_cmd="$RGBGFX -c#none,#fff,#000 -o none_round_trip.2bpp -r 1 out.png"
+reconvert_cmd="$RGBGFX -c#none,#fff,#000 -o result.2bpp out.png"
+compare_cmd="cmp none_round_trip.2bpp result.2bpp"
+new_test "$reverse_cmd && $reconvert_cmd && $compare_cmd"
+test || fail $?
+
 # Remove temporaries (also ignored by Git) created by the above tests
-rm -f out*.png result.png
+rm -f out*.png result.png result.2bpp
 
 for f in *.png; do
 	flags="$([[ -e "${f%.png}.flags" ]] && echo "@${f%.png}.flags")"