validate_build over settings

conans/client/graph/graph_binaries.py

@@ -50,6 +50,7 @@ def _evaluate_build(node, build_mode):
             conanfile.output.info('Forced build from source')
             node.binary = BINARY_BUILD
             node.prev = None
+            _call_validate_build(node)
             return True
 
     def _evaluate_clean_pkg_folder_dirty(self, node, package_layout, pref):
@@ -178,6 +179,7 @@ def _evaluate_node(self, node, build_mode, update, remotes):
             pref = PackageReference(locked.ref, locked.package_id, locked.prev)  # Keep locked PREV
             self._process_node(node, pref, build_mode, update, remotes)
             if node.binary == BINARY_MISSING and build_mode.allowed(node.conanfile):
+                _call_validate_build(node)
                 node.binary = BINARY_BUILD
             if node.binary == BINARY_BUILD:
                 locked.unlock_prev()
@@ -232,6 +234,7 @@ def _evaluate_node(self, node, build_mode, update, remotes):
                         node.binary = BINARY_INVALID
                 if node.binary == BINARY_MISSING and build_mode.allowed(node.conanfile):
                     node.binary = BINARY_BUILD
+                    _call_validate_build(conanfile)
 
             if locked:
                 # package_id was not locked, this means a base lockfile that is being completed
@@ -295,6 +298,7 @@ def _process_node(self, node, pref, build_mode, update, remotes):
                     conanfile.output.info("Outdated package!")
                     node.binary = BINARY_BUILD
                     node.prev = None
+                    _call_validate_build(conanfile)
                 else:
                     conanfile.output.info("Package is up to date")
 
@@ -451,3 +455,14 @@ def reevaluate_node(self, node, remotes, build_mode, update):
         output.info("Binary for updated ID from: %s" % node.binary)
         if node.binary == BINARY_BUILD:
             output.info("Binary for the updated ID has to be built")
+
+
+def _call_validate_build(node):
+    conanfile = node.conanfile
+    if hasattr(conanfile, "validate_build") and callable(conanfile.validate_build):
+        with conanfile_exception_formatter(str(conanfile), "validate_build"):
+            try:
+                conanfile.validate_build()
+            except ConanInvalidConfiguration as e:
+                conanfile.info.invalid = str(e)
+                node.binary = BINARY_INVALID

conans/test/integration/graph/test_validate_build.py

@@ -0,0 +1,42 @@
+import textwrap
+
+from conans.test.utils.tools import TestClient
+
+
+def test_basic_validate_build_test():
+
+    t = TestClient()
+    conanfile = textwrap.dedent("""
+    from conan import ConanFile
+    from conans.errors import ConanInvalidConfiguration
+
+    class myConan(ConanFile):
+        name = "foo"
+        version = "1.0"
+        settings = "os", "arch", "compiler"
+
+        def validate_build(self):
+            if self.settings.compiler == "gcc":
+                raise ConanInvalidConfiguration("This doesn't build in GCC")
+
+        def package_id(self):
+            del self.info.settings.compiler
+    """)
+
+    settings_gcc = "-s compiler=gcc -s compiler.libcxx=libstdc++11 -s compiler.version=11"
+    settings_clang = "-s compiler=clang -s compiler.libcxx=libc++ -s compiler.version=8"
+
+    t.save({"conanfile.py": conanfile})
+    t.run(f"create . {settings_gcc}", assert_error=True)
+
+    assert "This doesn't build in GCC" in t.out
+
+    t.run(f"create . {settings_clang}")
+
+    # Now with GCC again, but now we have the binary, we don't need to build, so it doesn't fail
+    t.run(f"create . {settings_gcc} --build missing")
+    assert "foo/1.0: Already installed!" in t.out
+
+    # But if I force the build... it will fail
+    t.run(f"create . {settings_gcc} ", assert_error=True)
+    assert "This doesn't build in GCC" in t.out