Use a stub compiler wrapper on windows

lib/spack/spack/solver/asp.py

@@ -1506,7 +1506,7 @@ def __init__(self, tests: bool = False):
             set
         )
 
-        self.possible_compilers: List[KnownCompiler] = []
+        self.possible_compilers: List[spack.spec.Spec] = []
         self.possible_oses: Set = set()
         self.variant_values_from_specs: Set = set()
         self.version_constraints: Set = set()
@@ -3151,7 +3151,6 @@ def define_runtime_constraints(self):
 
             # FIXME (compiler as nodes): think of using isinstance(compiler_cls, WrappedCompiler)
             # Add a dependency on the compiler wrapper
-            if sys.platform != "win32":
             recorder("*").depends_on(
                 "compiler-wrapper",
                 when=f"%{compiler.name}@{compiler.versions}",

var/spack/repos/builtin/packages/compiler-wrapper/package.py

@@ -3,6 +3,7 @@
 # SPDX-License-Identifier: (Apache-2.0 OR MIT)
 import pathlib
 import shutil
+import sys
 from typing import List
 
 import archspec.cpu
@@ -39,13 +40,15 @@ class CompilerWrapper(Package):
 
     license("Apache-2.0 OR MIT")
 
+    if sys.platform != "win32":
         version(
             "1.0",
-        sha256="92924570efbc0f388bbbeb87188e05537008bc25069529f7b519b4e48d7ddfb6",
+            sha256="84a26f8f37329bcdfb41d23a8a4f4c46efbede983eb73737135c95a4c126b5b7",
             expand=False,
         )
-
-    conflicts("platform=windows")
+    else:
+        version("1.0")
+        has_code = False
 
     def bin_dir(self) -> pathlib.Path:
         # This adds an extra "spack" subdir, so that the script and symlinks don't get
@@ -53,6 +56,14 @@ def bin_dir(self) -> pathlib.Path:
         return pathlib.Path(str(self.prefix)) / "spack" / "bin"
 
     def install(self, spec, prefix):
+        if sys.platform == "win32":
+            placeholder = self.bin_dir() / "placeholder-wrapper"
+            placeholder.parent.mkdir(parents=True)
+            placeholder.write_text(
+                "This file is a placeholder for the compiler wrapper on Windows."
+            )
+            return
+
         cc_script = pathlib.Path(self.stage.source_path) / "cc.sh"
         bin_dir = self.bin_dir()
 
@@ -125,6 +136,9 @@ def install(self, spec, prefix):
             (bin_dir / subdir / name).symlink_to(installed_script)
 
     def setup_dependent_build_environment(self, env, dependent_spec):
+        if sys.platform == "win32":
+            return
+
         _var_list = []
         if dependent_spec.dependencies(virtuals=("c",)):
             _var_list.append(("c", "cc", "CC", "SPACK_CC"))