Disallow invalid triplet names passed via --triplet (#1474)

src/vcpkg-test/input.cpp

@@ -105,6 +105,18 @@ See )" + docs::triplets_url + R"( for more information.
     REQUIRE(maybe_check.error() == expected_error);
 }
 
+TEST_CASE ("check_triplet rejects malformed triplet", "[input][check_triplet]")
+{
+    TripletDatabase db;
+    db.available_triplets.push_back(TripletFile{"invalid.triplet_name", "invalid.triplet_name.cmake"});
+    auto maybe_check = check_triplet("invalid.triplet_name", db);
+    REQUIRE(!maybe_check.has_value());
+    static constexpr StringLiteral expected_error{
+        "error: expected the end of input parsing a package spec; this usually means the indicated character is not "
+        "allowed to be in a package spec. Port, triplet, and feature names are all lowercase alphanumeric+hypens."};
+    REQUIRE(maybe_check.error() == expected_error);
+}
+
 TEST_CASE ("check_and_get_package_spec validates the triplet", "[input][check_and_get_package_spec]")
 {
     TripletDatabase db;

src/vcpkg/input.cpp

@@ -1,6 +1,6 @@
-
 #include <vcpkg/base/checks.h>
 #include <vcpkg/base/messages.h>
+#include <vcpkg/base/parse.h>
 #include <vcpkg/base/strings.h>
 
 #include <vcpkg/commands.help.h>
@@ -26,6 +26,12 @@ namespace vcpkg
     {
         // Intentionally show the lowercased string
         auto as_lower = Strings::ascii_to_lowercase(name);
+
+        if (std::find_if_not(name.begin(), name.end(), ParserBase::is_package_name_char) != name.end())
+        {
+            return msg::format_error(msgParseQualifiedSpecifierNotEof);
+        }
+
         if (!database.is_valid_triplet_canonical_name(as_lower))
         {
             LocalizedString result = msg::format_error(msgInvalidTriplet, msg::triplet = as_lower);