From f45bb1899bdb15efc8bf042a65b5e332f27b66d1 Mon Sep 17 00:00:00 2001
From: SpaceIm <30052553+SpaceIm@users.noreply.github.com>
Date: Tue, 12 Dec 2023 21:55:54 +0100
Subject: [PATCH] (#20089) protobuf: improve discovery of protoc executable in
 build context

* improve discovery of protoc executable in build context

* addd more comments

* fix test package
---
 recipes/protobuf/all/conanfile.py             | 19 ++++++++++++++++---
 .../protobuf/all/test_package/conanfile.py    | 13 +++----------
 2 files changed, 19 insertions(+), 13 deletions(-)

diff --git a/recipes/protobuf/all/conanfile.py b/recipes/protobuf/all/conanfile.py
index eb5f365e1eb561..f696a278806848 100644
--- a/recipes/protobuf/all/conanfile.py
+++ b/recipes/protobuf/all/conanfile.py
@@ -124,20 +124,33 @@ def _patch_sources(self):
         protoc_filename = "protoc" + exe_ext
         module_folder_depth = len(os.path.normpath(self._cmake_install_base_path).split(os.path.sep))
         protoc_rel_path = "{}bin/{}".format("".join(["../"] * module_folder_depth), protoc_filename)
-        protoc_target = textwrap.dedent("""\
+        protoc_target = textwrap.dedent(f"""\
             if(NOT TARGET protobuf::protoc)
+                # Locate protoc executable
+                ## Workaround for legacy "cmake" generator in case of cross-build
                 if(CMAKE_CROSSCOMPILING)
-                    find_program(PROTOC_PROGRAM protoc PATHS ENV PATH NO_DEFAULT_PATH)
+                    find_program(PROTOC_PROGRAM NAMES protoc PATHS ENV PATH NO_DEFAULT_PATH)
                 endif()
+                ## And here this will work fine with "CMakeToolchain" (for native & cross-build)
+                ## and legacy "cmake" generator in case of native build
+                if(NOT PROTOC_PROGRAM)
+                    find_program(PROTOC_PROGRAM NAMES protoc)
+                endif()
+                ## Last resort: we search in package folder directly
                 if(NOT PROTOC_PROGRAM)
                     set(PROTOC_PROGRAM \"${{CMAKE_CURRENT_LIST_DIR}}/{protoc_rel_path}\")
                 endif()
                 get_filename_component(PROTOC_PROGRAM \"${{PROTOC_PROGRAM}}\" ABSOLUTE)
+
+                # Give opportunity to users to provide an external protoc executable
+                # (this is a feature of official FindProtobuf.cmake)
                 set(Protobuf_PROTOC_EXECUTABLE ${{PROTOC_PROGRAM}} CACHE FILEPATH \"The protoc compiler\")
+
+                # Create executable imported target protobuf::protoc
                 add_executable(protobuf::protoc IMPORTED)
                 set_property(TARGET protobuf::protoc PROPERTY IMPORTED_LOCATION ${{Protobuf_PROTOC_EXECUTABLE}})
             endif()
-        """.format(protoc_rel_path=protoc_rel_path))
+        """)
         replace_in_file(self,
             protobuf_config_cmake,
             "include(\"${CMAKE_CURRENT_LIST_DIR}/protobuf-targets.cmake\")",
diff --git a/recipes/protobuf/all/test_package/conanfile.py b/recipes/protobuf/all/test_package/conanfile.py
index 3823d923c46842..81404c86104a87 100644
--- a/recipes/protobuf/all/test_package/conanfile.py
+++ b/recipes/protobuf/all/test_package/conanfile.py
@@ -1,13 +1,12 @@
 from conan import ConanFile
-from conan.tools.build import can_run, cross_building
+from conan.tools.build import can_run
 from conan.tools.cmake import cmake_layout, CMake, CMakeToolchain
-from conan.tools.env import VirtualBuildEnv, VirtualRunEnv
 import os
 
 
 class TestPackageConan(ConanFile):
     settings = "os", "arch", "compiler", "build_type"
-    generators = "CMakeDeps"
+    generators = "CMakeDeps", "VirtualBuildEnv", "VirtualRunEnv"
     test_type = "explicit"
 
     def layout(self):
@@ -17,15 +16,9 @@ def requirements(self):
         self.requires(self.tested_reference_str)
 
     def build_requirements(self):
-        if cross_building(self) and hasattr(self, "settings_build"):
-            self.tool_requires(self.tested_reference_str)
+        self.tool_requires(self.tested_reference_str)
 
     def generate(self):
-        VirtualRunEnv(self).generate()
-        if cross_building(self) and hasattr(self, "settings_build"):
-            VirtualBuildEnv(self).generate()
-        else:
-            VirtualRunEnv(self).generate(scope="build")
         tc = CMakeToolchain(self)
         tc.cache_variables["protobuf_LITE"] = self.dependencies[self.tested_reference_str].options.lite
         tc.generate()