fix for [platform_tool_requires] in build context

conans/client/graph/graph_builder.py

@@ -222,8 +222,16 @@ def _resolve_recipe(self, ref, graph_lock):
     @staticmethod
     def _resolved_system(node, require, profile_build, profile_host, resolve_prereleases):
         profile = profile_build if node.context == CONTEXT_BUILD else profile_host
-        dep_type = "platform_tool_requires" if require.build else "platform_requires"
-        system_reqs = getattr(profile, dep_type)
+        if node.context == CONTEXT_BUILD:
+            # If we are in the build context, the platform_tool_requires ALSO applies to the
+            # regular requires. It is not possible in the build context to have tool-requires
+            # and regular requires to the same package from Conan and from Platform
+            system_reqs = profile.platform_tool_requires
+            if not require.build:
+                system_reqs = system_reqs + profile.platform_requires
+        else:
+            system_reqs = profile.platform_tool_requires if require.build \
+                else profile.platform_requires
         if system_reqs:
             version_range = require.version_range
             for d in system_reqs:

conans/client/graph/install_graph.py

@@ -4,7 +4,7 @@
 
 from conan.api.output import ConanOutput
 from conans.client.graph.graph import RECIPE_CONSUMER, RECIPE_VIRTUAL, BINARY_SKIP, \
-    BINARY_MISSING, BINARY_INVALID, Overrides, BINARY_BUILD, BINARY_EDITABLE_BUILD
+    BINARY_MISSING, BINARY_INVALID, Overrides, BINARY_BUILD, BINARY_EDITABLE_BUILD, BINARY_PLATFORM
 from conans.errors import ConanInvalidConfiguration, ConanException
 from conans.model.package_ref import PkgReference
 from conans.model.recipe_ref import RecipeReference
@@ -370,7 +370,8 @@ def deserialize(data, filename):
 
     def _initialize_deps_graph(self, deps_graph):
         for node in deps_graph.ordered_iterate():
-            if node.recipe in (RECIPE_CONSUMER, RECIPE_VIRTUAL) or node.binary == BINARY_SKIP:
+            if node.recipe in (RECIPE_CONSUMER, RECIPE_VIRTUAL) \
+                    or node.binary in (BINARY_SKIP, BINARY_PLATFORM):
                 continue
 
             key = node.ref if self._order == "recipe" else node.pref

conans/client/installer.py

@@ -7,7 +7,7 @@
 from conans.client.conanfile.package import run_package_method
 from conans.client.generators import write_generators
 from conans.client.graph.graph import BINARY_BUILD, BINARY_CACHE, BINARY_DOWNLOAD, BINARY_EDITABLE, \
-    BINARY_PLATFORM, BINARY_UPDATE, BINARY_EDITABLE_BUILD, BINARY_SKIP
+    BINARY_UPDATE, BINARY_EDITABLE_BUILD, BINARY_SKIP
 from conans.client.graph.install_graph import InstallGraph
 from conans.client.source import retrieve_exports_sources, config_source
 from conans.errors import (ConanException, conanfile_exception_formatter, conanfile_remove_attr)
@@ -295,9 +295,6 @@ def _download_pkg(self, package):
         self._remote_manager.get_package(node.pref, node.binary_remote)
 
     def _handle_package(self, package, install_reference, handled_count, total_count):
-        if package.binary == BINARY_PLATFORM:
-            return
-
         if package.binary in (BINARY_EDITABLE, BINARY_EDITABLE_BUILD):
             self._handle_node_editable(package)
             return

conans/test/integration/graph/test_platform_requires.py

@@ -58,6 +58,19 @@ def test_platform_requires_no_host(self):
         client.run("create . -pr=profile", assert_error=True)
         assert "ERROR: Package 'dep/1.0' not resolved: No remote defined" in client.out
 
+    def test_platform_requires_build_context(self):
+        """
+        platform_requires must work in the build context too
+        """
+        client = TestClient(light=True)
+        client.save({"tool/conanfile.py": GenConanfile("tool", "1.0").with_requires("dep/1.0"),
+                     "pkg/conanfile.py": GenConanfile("pkg", "1.0").with_tool_requires("tool/1.0"),
+                     "profile": "[settings]\nos=Linux\n[platform_requires]\ndep/1.0"})
+        client.run("create tool -pr:b=profile --build-require")
+        assert "dep/1.0 - Platform" in client.out
+        client.run("create pkg -pr:b=profile")
+        assert "dep/1.0 - Platform" in client.out
+
     def test_graph_info_platform_requires_range(self):
         """
         graph info doesn't crash
@@ -136,6 +149,15 @@ def generate(self):
         assert "ERROR: Package 'dep/1.1' not resolved" in client.out
 
 
+class TestPlatformTestRequires:
+    def test_platform_requires(self):
+        client = TestClient()
+        client.save({"conanfile.py": GenConanfile("pkg", "1.0").with_test_requires("dep/1.0"),
+                     "profile": "[platform_requires]\ndep/1.0"})
+        client.run("create . -pr=profile")
+        assert "dep/1.0 - Platform" in client.out
+
+
 class TestPlatformRequiresLock:
 
     def test_platform_requires_range(self):

conans/test/integration/graph/test_system_tools.py

@@ -136,6 +136,26 @@ def generate(self):
         client.run("install . -pr=profile", assert_error=True)
         assert "ERROR: Package 'tool/1.1' not resolved" in client.out
 
+    def test_require_build_context(self):
+        """ https://github.com/conan-io/conan/issues/15659
+        app -> libcurl --(tool-require)--> libtool -> automake -> autoconf
+                                             \\--(br)-> automake -> autoconf
+        """
+        c = TestClient()
+        c.save({"autoconf/conanfile.py": GenConanfile("autoconf", "0.1"),
+                "automake/conanfile.py": GenConanfile("automake", "0.1").with_requires("autoconf/0.1"),
+                "libtool/conanfile.py": GenConanfile("libtool", "0.1").with_requires("automake/0.1")
+                                                                      .with_tool_requires("automake/0.1"),
+                "libcurl/conanfile.py": GenConanfile("libcurl", "0.1").with_tool_requires("libtool/0.1"),
+                "app/conanfile.py": GenConanfile().with_requires("libcurl/0.1"),
+                "profile_build": "[settings]\nos=Linux\n[platform_tool_requires]\nautomake/0.1"})
+        c.run("create autoconf")
+        c.run("create automake")
+        c.run("export libtool")
+        c.run("export libcurl")
+        c.run("install app -pr:b=profile_build --build=missing")
+        assert "Install finished successfully" in c.out
+
 
 class TestToolRequiresLock: