multiple modules might provide an extension with the same name

...especially in case of augments. In this test case, the other module
"adds" an extension instance with the same unqualified name as an
existing extension instance.

This was inspired by a patch from Bedrich
(Ib0dfb68afaf0f74d3defe87b16b7c34457cc4899). I was wondering why that
one was adding the .module() method for both Extension and
ExtensionInstance; now I know.

Co-authored-by: Bedřich Schindler <bedrich.schindler@gmail.com>
Change-Id: Ib839695a67b3b102f487b18a835c9c903e0ffdcd

Author: jktjkt

include/libyang-cpp/Module.hpp

@@ -96,6 +96,7 @@ class LIBYANG_CPP_EXPORT Module {
     friend Context;
     friend DataNode;
     friend Extension;
+    friend ExtensionInstance;
     friend Meta;
     friend Identity;
     friend SchemaNode;
@@ -161,6 +162,7 @@ class LIBYANG_CPP_EXPORT Identity {
  */
 class LIBYANG_CPP_EXPORT ExtensionInstance {
 public:
+    Module module() const;
     Extension definition() const;
     std::optional<std::string> argument() const;
 

src/Module.cpp

@@ -390,6 +390,16 @@ ExtensionInstance::ExtensionInstance(const lysc_ext_instance* instance, std::sha
 {
 }
 
+/**
+ * @brief Returns the module of this extension instance.
+ *
+ * Wraps `lysc_ext_instance::module`.
+ */
+Module ExtensionInstance::module() const
+{
+    return Module{m_instance->module, m_ctx};
+}
+
 /**
  * @brief Returns the argument name
  *

tests/example_schema.hpp

@@ -754,3 +754,16 @@ module with-extensions {
   }
 }
 )"s;
+const auto augmented_extensions_module = R"(
+module augmenting-extensions {
+  yang-version 1.1;
+  prefix "ae";
+  namespace "ae";
+  import with-extensions {
+    prefix "we";
+  }
+  augment "/we:c" {
+    we:annotation last-modified;
+  }
+}
+)"s;

tests/schema_node.cpp

@@ -356,12 +356,32 @@ TEST_CASE("SchemaNode")
         REQUIRE(mod.extensionInstances().size() == 0);
         auto elem = ctx->findPath("/with-extensions:c");
         REQUIRE(elem.extensionInstances().size() == 2);
+        REQUIRE(elem.extensionInstances()[0].module().name() == "with-extensions");
         REQUIRE(elem.extensionInstances()[0].definition().module().name() == "ietf-netconf-acm");
         REQUIRE(elem.extensionInstances()[0].definition().name() == "default-deny-write");
         REQUIRE(!elem.extensionInstances()[0].argument());
+        REQUIRE(elem.extensionInstances()[1].module().name() == "with-extensions");
         REQUIRE(elem.extensionInstances()[1].definition().module().name() == "with-extensions");
         REQUIRE(elem.extensionInstances()[1].definition().name() == "annotation");
         REQUIRE(elem.extensionInstances()[1].argument() == "last-modified");
+
+        auto mod2 = ctx->parseModule(augmented_extensions_module, libyang::SchemaFormat::YANG);
+        REQUIRE(mod2.extensionInstances().size() == 0);
+        elem = ctx->findPath("/with-extensions:c");
+        REQUIRE(elem.extensionInstances().size() == 3);
+        // the augment adds a new extension, and libyang places that at index 0
+        REQUIRE(elem.extensionInstances()[0].module().name() == "augmenting-extensions");
+        REQUIRE(elem.extensionInstances()[0].definition().module().name() == "with-extensions");
+        REQUIRE(elem.extensionInstances()[0].definition().name() == "annotation");
+        REQUIRE(elem.extensionInstances()[0].argument() == "last-modified");
+        REQUIRE(elem.extensionInstances()[1].module().name() == "with-extensions");
+        REQUIRE(elem.extensionInstances()[1].definition().module().name() == "ietf-netconf-acm");
+        REQUIRE(elem.extensionInstances()[1].definition().name() == "default-deny-write");
+        REQUIRE(!elem.extensionInstances()[1].argument());
+        REQUIRE(elem.extensionInstances()[2].module().name() == "with-extensions");
+        REQUIRE(elem.extensionInstances()[2].definition().module().name() == "with-extensions");
+        REQUIRE(elem.extensionInstances()[2].definition().name() == "annotation");
+        REQUIRE(elem.extensionInstances()[2].argument() == "last-modified");
     }
 
     DOCTEST_SUBCASE("SchemaNode::operator==")