fix: ignore empty args when splitting commands (fix #3239)

src/lib/src/functions.cpp

@@ -64,6 +64,14 @@ QString lastErrorString()
 }
 
 
+/**
+ * Re-implementation of QProcess::splitCommand that supports both single and double quotes.
+ *
+ * For example, `"a b" 'c d' e` will be turned into ("a b", "c d", "e").
+ *
+ * @param command The command to split into a list of process arguments.
+ * @return The list of arguments to start the process with.
+ */
 QStringList splitCommand(const QString &command)
 {
 	QStringList args;
@@ -114,8 +122,10 @@ QStringList splitCommand(const QString &command)
 
 		// If we finally reached a space outside a quoted argument, we flush
 		if (!inQuote && c.isSpace()) {
-			args += tmp;
-			tmp.clear();
+			if (!tmp.isEmpty()) {
+				args += tmp;
+				tmp.clear();
+			}
 		} else {
 			tmp += c;
 		}

src/lib/tests/src/functions-test.cpp

@@ -2,6 +2,7 @@
 #include <QFile>
 #include <QFileInfo>
 #include <QFont>
+#include <QProcess>
 #include <QRect>
 #include <QSettings>
 #include <QTemporaryFile>
@@ -491,6 +492,13 @@ TEST_CASE("Functions")
 			REQUIRE(splitCommand("a b c") == QStringList { "a", "b", "c" });
 		}
 
+		SECTION("Multiple spaces")
+		{
+			REQUIRE(splitCommand(" ") == QStringList {});
+			REQUIRE(splitCommand(" a ") == QStringList { "a" });
+			REQUIRE(splitCommand(" a  b   c ") == QStringList { "a", "b", "c" });
+		}
+
 		SECTION("Backslash escape")
 		{
 			REQUIRE(splitCommand("a\\ b c") == QStringList { "a b", "c" });
@@ -523,6 +531,26 @@ TEST_CASE("Functions")
 			REQUIRE(splitCommand("a \"'b' c\"") == QStringList { "a", "'b' c" });
 			REQUIRE(splitCommand("a \"'b' \"\"\" c\"") == QStringList { "a", "'b' \" c" });
 		}
+
+		SECTION("Consistent with QProcess::splitCommand")
+		{
+			static const QStringList tests {
+				"",
+				" ",
+				"a",
+				" a ",
+				"a b c",
+				" a  b   c ",
+				"\"a b\" c",
+				"a \"b c\"",
+				"\"a b c\"",
+				"\"a b \"\"\" c\"",
+			};
+
+			for (const QString &str : tests) {
+				REQUIRE(splitCommand(str) == QProcess::splitCommand(str));
+			}
+		}
 	}
 
 	SECTION("getKeySequence")