diff --git a/python/google/protobuf/pyext/descriptor_containers.cc b/python/google/protobuf/pyext/descriptor_containers.cc
index 8c038e9dc9..f38fdc74e5 100644
--- a/python/google/protobuf/pyext/descriptor_containers.cc
+++ b/python/google/protobuf/pyext/descriptor_containers.cc
@@ -54,6 +54,8 @@
 // This inclusion must appear before all the others.
 #include <Python.h>
 
+#include <string>
+
 #include "google/protobuf/pyext/descriptor_containers.h"
 // clang-format on
 
diff --git a/python/google/protobuf/pyext/descriptor_database.cc b/python/google/protobuf/pyext/descriptor_database.cc
index 7ef94b3860..e547306d51 100644
--- a/python/google/protobuf/pyext/descriptor_database.cc
+++ b/python/google/protobuf/pyext/descriptor_database.cc
@@ -34,6 +34,8 @@
 #include "google/protobuf/pyext/descriptor_database.h"
 
 #include <cstdint>
+#include <string>
+#include <vector>
 
 #include "google/protobuf/stubs/logging.h"
 #include "google/protobuf/stubs/common.h"
diff --git a/python/google/protobuf/pyext/descriptor_database.h b/python/google/protobuf/pyext/descriptor_database.h
index 598466e981..108a8583b3 100644
--- a/python/google/protobuf/pyext/descriptor_database.h
+++ b/python/google/protobuf/pyext/descriptor_database.h
@@ -34,6 +34,9 @@
 #define PY_SSIZE_T_CLEAN
 #include <Python.h>
 
+#include <string>
+#include <vector>
+
 #include "google/protobuf/descriptor_database.h"
 
 namespace google {
diff --git a/python/google/protobuf/pyext/descriptor_pool.cc b/python/google/protobuf/pyext/descriptor_pool.cc
index 0f25ed3539..db14ae6624 100644
--- a/python/google/protobuf/pyext/descriptor_pool.cc
+++ b/python/google/protobuf/pyext/descriptor_pool.cc
@@ -30,7 +30,10 @@
 
 // Implements the DescriptorPool, which collects all descriptors.
 
+#include <string>
 #include <unordered_map>
+#include <utility>
+#include <vector>
 
 #define PY_SSIZE_T_CLEAN
 #include <Python.h>
diff --git a/python/google/protobuf/pyext/extension_dict.cc b/python/google/protobuf/pyext/extension_dict.cc
index d03ad87d23..806af4f865 100644
--- a/python/google/protobuf/pyext/extension_dict.cc
+++ b/python/google/protobuf/pyext/extension_dict.cc
@@ -35,6 +35,7 @@
 
 #include <cstdint>
 #include <memory>
+#include <vector>
 
 #include "google/protobuf/stubs/logging.h"
 #include "google/protobuf/stubs/common.h"
diff --git a/python/google/protobuf/pyext/map_container.cc b/python/google/protobuf/pyext/map_container.cc
index e5496105bb..76c4d888a2 100644
--- a/python/google/protobuf/pyext/map_container.cc
+++ b/python/google/protobuf/pyext/map_container.cc
@@ -34,6 +34,7 @@
 
 #include <cstdint>
 #include <memory>
+#include <string>
 
 #include "google/protobuf/stubs/logging.h"
 #include "google/protobuf/stubs/common.h"
diff --git a/python/google/protobuf/pyext/message.cc b/python/google/protobuf/pyext/message.cc
index 13495851f5..7990e95ac1 100644
--- a/python/google/protobuf/pyext/message.cc
+++ b/python/google/protobuf/pyext/message.cc
@@ -38,6 +38,7 @@
 #include <cstdint>
 #include <map>
 #include <memory>
+#include <set>
 #include <string>
 #include <vector>
 
diff --git a/python/google/protobuf/pyext/message_factory.cc b/python/google/protobuf/pyext/message_factory.cc
index bcbd7d8d7b..27aa5e4417 100644
--- a/python/google/protobuf/pyext/message_factory.cc
+++ b/python/google/protobuf/pyext/message_factory.cc
@@ -29,6 +29,7 @@
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 #include <unordered_map>
+#include <utility>
 
 #define PY_SSIZE_T_CLEAN
 #include <Python.h>
diff --git a/python/google/protobuf/pyext/repeated_scalar_container.cc b/python/google/protobuf/pyext/repeated_scalar_container.cc
index 1a39468e96..57746dcf77 100644
--- a/python/google/protobuf/pyext/repeated_scalar_container.cc
+++ b/python/google/protobuf/pyext/repeated_scalar_container.cc
@@ -35,6 +35,7 @@
 
 #include <cstdint>
 #include <memory>
+#include <string>
 
 #include "google/protobuf/stubs/common.h"
 #include "google/protobuf/stubs/logging.h"
diff --git a/src/google/protobuf/compiler/cpp/helpers.h b/src/google/protobuf/compiler/cpp/helpers.h
index 55fe178cdc..19120e313c 100644
--- a/src/google/protobuf/compiler/cpp/helpers.h
+++ b/src/google/protobuf/compiler/cpp/helpers.h
@@ -220,7 +220,7 @@ inline const Descriptor* FieldScope(const FieldDescriptor* field) {
 std::string FieldMessageTypeName(const FieldDescriptor* field,
                                  const Options& options);
 
-// Get the C++ type name for a primitive type (e.g. "double", "::google::protobuf::int32", etc.).
+// Get the C++ type name for a primitive type (e.g. "double", "::int32", etc.).
 const char* PrimitiveTypeName(FieldDescriptor::CppType type);
 std::string PrimitiveTypeName(const Options& options,
                               FieldDescriptor::CppType type);
diff --git a/src/google/protobuf/io/printer.cc b/src/google/protobuf/io/printer.cc
index 0b8e053ea2..c4d184733b 100644
--- a/src/google/protobuf/io/printer.cc
+++ b/src/google/protobuf/io/printer.cc
@@ -169,7 +169,13 @@ void Printer::Emit(
 
   absl::flat_hash_map<absl::string_view,
                       absl::variant<std::string, std::function<void()>>>
-      map = vars;
+      map;
+  map.reserve(vars.size());
+  for (auto& var : vars) {
+    auto result = map.insert(var);
+    GOOGLE_CHECK(result.second) << "repeated variable in Emit() call: \"" << var.first
+                         << "\"";
+  }
 
   var_lookups_.emplace_back([&map](absl::string_view var) -> LookupResult {
     auto it = map.find(var);
diff --git a/src/google/protobuf/port_def.inc b/src/google/protobuf/port_def.inc
index bbfc299d19..ac4b2b9ed3 100644
--- a/src/google/protobuf/port_def.inc
+++ b/src/google/protobuf/port_def.inc
@@ -875,6 +875,13 @@
 #undef PACKAGE
 #endif
 
+// linux is a legacy MACRO defined in most popular C++ standards.
+#ifdef linux
+#pragma push_macro("linux")
+#undef linux
+#define PROTOBUF_DID_UNDEF_LINUX
+#endif
+
 // Windows declares several inconvenient macro names.  We #undef them and then
 // restore them in port_undef.inc.
 #ifdef _WIN32
diff --git a/src/google/protobuf/port_undef.inc b/src/google/protobuf/port_undef.inc
index 4dd6586811..e991502faa 100644
--- a/src/google/protobuf/port_undef.inc
+++ b/src/google/protobuf/port_undef.inc
@@ -121,12 +121,17 @@
 
 #undef PROTOBUF_FUTURE_FINAL
 
+// Restore macros that may have been #undef'd in port_def.inc.
+
 #ifdef PROTOBUF_DID_UNDEF_PACKAGE
 #pragma pop_macro("PACKAGE")
 #undef PROTOBUF_DID_UNDEF_PACKAGE
 #endif
 
-// Restore macro that may have been #undef'd in port_def.inc.
+#ifdef PROTOBUF_DID_UNDEF_LINUX
+#pragma pop_macro("linux")
+#endif
+
 #ifdef _WIN32
 #pragma pop_macro("CREATE_NEW")
 #pragma pop_macro("DELETE")
diff --git a/src/google/protobuf/text_format.cc b/src/google/protobuf/text_format.cc
index 8633e88699..cf2afa2ffb 100644
--- a/src/google/protobuf/text_format.cc
+++ b/src/google/protobuf/text_format.cc
@@ -53,6 +53,7 @@
 #include "google/protobuf/stubs/strutil.h"
 #include "absl/strings/ascii.h"
 #include "absl/strings/escaping.h"
+#include "absl/strings/numbers.h"
 #include "absl/strings/str_cat.h"
 #include "absl/strings/str_join.h"
 #include "absl/strings/string_view.h"