python pyi print "import datetime" for Duration/Timestamp field (#21885)

PiperOrigin-RevId: 761639872

Author: anandolee

src/google/protobuf/compiler/python/pyi_generator.cc

@@ -73,6 +73,7 @@ struct ImportModules {
   bool has_union = false;       // typing.Union
   bool has_callable = false;    // typing.Callable
   bool has_well_known_type = false;
+  bool has_datetime = false;
 };
 
 // Checks whether a descriptor name matches a well-known type.
@@ -112,8 +113,15 @@ void CheckImportModules(const Descriptor* descriptor,
     if (field->is_map()) {
       import_modules->has_mapping = true;
       const FieldDescriptor* value_des = field->message_type()->field(1);
-      if (value_des->cpp_type() == FieldDescriptor::CPPTYPE_MESSAGE ||
-          value_des->cpp_type() == FieldDescriptor::CPPTYPE_ENUM) {
+      if (value_des->cpp_type() == FieldDescriptor::CPPTYPE_MESSAGE) {
+        import_modules->has_union = true;
+        const absl::string_view name = value_des->message_type()->full_name();
+        if (name == "google.protobuf.Duration" ||
+            name == "google.protobuf.Timestamp") {
+          import_modules->has_datetime = true;
+        }
+      }
+      if (value_des->cpp_type() == FieldDescriptor::CPPTYPE_ENUM) {
         import_modules->has_union = true;
       }
     } else {
@@ -123,6 +131,11 @@ void CheckImportModules(const Descriptor* descriptor,
       if (field->cpp_type() == FieldDescriptor::CPPTYPE_MESSAGE) {
         import_modules->has_union = true;
         import_modules->has_mapping = true;
+        const absl::string_view name = field->message_type()->full_name();
+        if (name == "google.protobuf.Duration" ||
+            name == "google.protobuf.Timestamp") {
+          import_modules->has_datetime = true;
+        }
       }
       if (field->cpp_type() == FieldDescriptor::CPPTYPE_ENUM) {
         import_modules->has_union = true;
@@ -170,21 +183,6 @@ void PyiGenerator::PrintImportForDescriptor(
 }
 
 void PyiGenerator::PrintImports() const {
-  // Prints imported dependent _pb2 files.
-  absl::flat_hash_set<std::string> seen_aliases;
-  bool has_importlib = false;
-  for (int i = 0; i < file_->dependency_count(); ++i) {
-    const FileDescriptor* dep = file_->dependency(i);
-    if (strip_nonfunctional_codegen_ && IsKnownFeatureProto(dep->name())) {
-      continue;
-    }
-    PrintImportForDescriptor(*dep, &seen_aliases, &has_importlib);
-    for (int j = 0; j < dep->public_dependency_count(); ++j) {
-      PrintImportForDescriptor(*dep->public_dependency(j), &seen_aliases,
-                               &has_importlib);
-    }
-  }
-
   // Checks what modules should be imported.
   ImportModules import_modules;
   if (file_->message_type_count() > 0) {
@@ -201,6 +199,24 @@ void PyiGenerator::PrintImports() const {
   for (int i = 0; i < file_->message_type_count(); i++) {
     CheckImportModules(file_->message_type(i), &import_modules);
   }
+  if (import_modules.has_datetime) {
+    printer_->Print("import datetime\n\n");
+  }
+
+  // Prints imported dependent _pb2 files.
+  absl::flat_hash_set<std::string> seen_aliases;
+  bool has_importlib = false;
+  for (int i = 0; i < file_->dependency_count(); ++i) {
+    const FileDescriptor* dep = file_->dependency(i);
+    if (strip_nonfunctional_codegen_ && IsKnownFeatureProto(dep->name())) {
+      continue;
+    }
+    PrintImportForDescriptor(*dep, &seen_aliases, &has_importlib);
+    for (int j = 0; j < dep->public_dependency_count(); ++j) {
+      PrintImportForDescriptor(*dep->public_dependency(j), &seen_aliases,
+                               &has_importlib);
+    }
+  }
 
   // Prints modules (e.g. _containers, _messages, typing) that are
   // required in the proto file.