CMake: disable Package Registry (#42149)

CMake may write and read from `~/.cmake` through `export(...)` and read `find_package(...)` respectively. We don't want this as it may influence the build in a non-deterministic way, so disable it for all versions of `cmake`.

lib/spack/spack/build_systems/cmake.py

@@ -58,6 +58,44 @@ def _maybe_set_python_hints(pkg: spack.package_base.PackageBase, args: List[str]
     )
 
 
+def _conditional_cmake_defaults(pkg: spack.package_base.PackageBase, args: List[str]) -> None:
+    """Set a few default defines for CMake, depending on its version."""
+    cmakes = pkg.spec.dependencies("cmake", dt.BUILD)
+
+    if len(cmakes) != 1:
+        return
+
+    cmake = cmakes[0]
+
+    # CMAKE_INTERPROCEDURAL_OPTIMIZATION only exists for CMake >= 3.9
+    try:
+        ipo = pkg.spec.variants["ipo"].value
+    except KeyError:
+        ipo = False
+
+    if cmake.satisfies("@3.9:"):
+        args.append(CMakeBuilder.define("CMAKE_INTERPROCEDURAL_OPTIMIZATION", ipo))
+
+    # Disable Package Registry: export(PACKAGE) may put files in the user's home directory, and
+    # find_package may search there. This is not what we want.
+
+    # Do not populate CMake User Package Registry
+    if cmake.satisfies("@3.15:"):
+        # see https://cmake.org/cmake/help/latest/policy/CMP0090.html
+        args.append(CMakeBuilder.define("CMAKE_POLICY_DEFAULT_CMP0090", "NEW"))
+    elif cmake.satisfies("@3.1:"):
+        # see https://cmake.org/cmake/help/latest/variable/CMAKE_EXPORT_NO_PACKAGE_REGISTRY.html
+        args.append(CMakeBuilder.define("CMAKE_EXPORT_NO_PACKAGE_REGISTRY", True))
+
+    # Do not use CMake User/System Package Registry
+    # https://cmake.org/cmake/help/latest/manual/cmake-packages.7.html#disabling-the-package-registry
+    if cmake.satisfies("@3.16:"):
+        args.append(CMakeBuilder.define("CMAKE_FIND_USE_PACKAGE_REGISTRY", False))
+    elif cmake.satisfies("@3.1:3.15"):
+        args.append(CMakeBuilder.define("CMAKE_FIND_PACKAGE_NO_PACKAGE_REGISTRY", False))
+        args.append(CMakeBuilder.define("CMAKE_FIND_PACKAGE_NO_SYSTEM_PACKAGE_REGISTRY", False))
+
+
 def generator(*names: str, default: Optional[str] = None):
     """The build system generator to use.
 
@@ -293,11 +331,6 @@ def std_args(pkg, generator=None):
         except KeyError:
             build_type = "RelWithDebInfo"
 
-        try:
-            ipo = pkg.spec.variants["ipo"].value
-        except KeyError:
-            ipo = False
-
         define = CMakeBuilder.define
         args = [
             "-G",
@@ -306,10 +339,6 @@ def std_args(pkg, generator=None):
             define("CMAKE_BUILD_TYPE", build_type),
         ]
 
-        # CMAKE_INTERPROCEDURAL_OPTIMIZATION only exists for CMake >= 3.9
-        if pkg.spec.satisfies("^cmake@3.9:"):
-            args.append(define("CMAKE_INTERPROCEDURAL_OPTIMIZATION", ipo))
-
         if primary_generator == "Unix Makefiles":
             args.append(define("CMAKE_VERBOSE_MAKEFILE", True))
 
@@ -318,6 +347,7 @@ def std_args(pkg, generator=None):
                 [define("CMAKE_FIND_FRAMEWORK", "LAST"), define("CMAKE_FIND_APPBUNDLE", "LAST")]
             )
 
+        _conditional_cmake_defaults(pkg, args)
         _maybe_set_python_hints(pkg, args)
 
         # Set up CMake rpath

lib/spack/spack/spec.py

@@ -1501,7 +1501,9 @@ def edge_attributes(self) -> str:
         result = f"{deptypes_str} {virtuals_str}".strip()
         return f"[{result}]"
 
-    def dependencies(self, name=None, deptype: Union[dt.DepTypes, dt.DepFlag] = dt.ALL):
+    def dependencies(
+        self, name=None, deptype: Union[dt.DepTypes, dt.DepFlag] = dt.ALL
+    ) -> List["Spec"]:
         """Return a list of direct dependencies (nodes in the DAG).
 
         Args:
@@ -1512,7 +1514,9 @@ def dependencies(self, name=None, deptype: Union[dt.DepTypes, dt.DepFlag] = dt.A
             deptype = dt.canonicalize(deptype)
         return [d.spec for d in self.edges_to_dependencies(name, depflag=deptype)]
 
-    def dependents(self, name=None, deptype: Union[dt.DepTypes, dt.DepFlag] = dt.ALL):
+    def dependents(
+        self, name=None, deptype: Union[dt.DepTypes, dt.DepFlag] = dt.ALL
+    ) -> List["Spec"]:
         """Return a list of direct dependents (nodes in the DAG).
 
         Args: