Fix issue with multiline array interpretation for toml (#1196)

if the first line only contained a single character.

Fixes #1195

Author: phlptp

include/CLI/impl/Config_inl.hpp

@@ -414,7 +414,7 @@ inline std::vector<ConfigItem> ConfigBase::from_config(std::istream &input) cons
                     }
                 }
                 items_buffer = {item};
-            } else if(item.size() > 1 && item.front() == aStart) {
+            } else if(!item.empty() && item.front() == aStart) {
                 for(std::string multiline; item.back() != aEnd && std::getline(input, multiline);) {
                     detail::trim(multiline);
                     item += multiline;

tests/ConfigFileTest.cpp

@@ -1510,6 +1510,57 @@ TEST_CASE_METHOD(TApp, "TOMLVector", "[config]") {
     CHECK(three == std::vector<int>({1, 2, 3}));
 }
 
+TEST_CASE_METHOD(TApp, "TOMLMultiLineVector", "[config]") {
+
+    TempFile tmptoml{"TestTomlTmp.toml"};
+
+    app.set_config("--config", tmptoml);
+
+    {
+        std::ofstream out{tmptoml};
+        out << "#this is a comment line\n";
+        out << "[default]\n";
+        out << "two=[\n";
+        out << "  2, 3\n";
+        out << "]\n";
+        out << "three=[\n\t1,\n\t2,\n\t3\n]\n";
+    }
+
+    std::vector<int> two, three;
+    app.add_option("--two", two)->expected(2)->required();
+    app.add_option("--three", three)->required();
+
+    run();
+
+    CHECK(two == std::vector<int>({2, 3}));
+    CHECK(three == std::vector<int>({1, 2, 3}));
+}
+
+TEST_CASE_METHOD(TApp, "TOMLMultiLineVector2", "[config]") {
+
+    TempFile tmptoml{"TestTomlTmp.toml"};
+
+    app.set_config("--config", tmptoml);
+
+    {
+        std::ofstream out{tmptoml};
+        out << "#this is a comment line\n";
+        out << "[default]\n";
+        out << "two=[\n";
+        out << "  2, 3]\n";
+        out << "three=[\n\t1,\n\t2,\n\t3\n]\n";
+    }
+
+    std::vector<int> two, three;
+    app.add_option("--two", two)->expected(2)->required();
+    app.add_option("--three", three)->required();
+
+    run();
+
+    CHECK(two == std::vector<int>({2, 3}));
+    CHECK(three == std::vector<int>({1, 2, 3}));
+}
+
 TEST_CASE_METHOD(TApp, "ColonValueSep", "[config]") {
 
     TempFile tmpini{"TestIniTmp.ini"};
@@ -1700,6 +1751,30 @@ TEST_CASE_METHOD(TApp, "TOMLStringVector", "[config]") {
     CHECK(three == std::vector<std::string>({"1", "2", "3"}));
 }
 
+TEST_CASE_METHOD(TApp, "TOMLStringVectorMultiline", "[config]") {
+
+    TempFile tmptoml{"TestTomlTmp.toml"};
+
+    app.set_config("--config", tmptoml);
+
+    {
+        std::ofstream out{tmptoml};
+        out << "#this is a comment line\n";
+        out << "[default]\n";
+        out << "two=[\n\t\t\"2\",\"3\"]\n";
+        out << "three=[\n    \"1\",\n    \"2\",\n    \"3\"\n]    \n";
+    }
+
+    std::vector<std::string> two, three;
+
+    app.add_option("--two", two)->required();
+    app.add_option("--three", three)->required();
+
+    run();
+    CHECK(two == std::vector<std::string>({"2", "3"}));
+    CHECK(three == std::vector<std::string>({"1", "2", "3"}));
+}
+
 TEST_CASE_METHOD(TApp, "IniVectorCsep", "[config]") {
 
     TempFile tmpini{"TestIniTmp.ini"};