add caching to resolver to reuse candidates for build time requirements

Signed-off-by: Shubh Bapna <[email protected]>

src/fromager/build_environment.py

@@ -53,7 +53,10 @@ def __init__(
         for r in all_reqs:
             try:
                 _, version = resolver.resolve(
-                    ctx=ctx, req=r, sdist_server_url=resolver.PYPI_SERVER_URL
+                    ctx=ctx,
+                    req=r,
+                    sdist_server_url=resolver.PYPI_SERVER_URL,
+                    req_type=req_type,
                 )
             except Exception as err:
                 resolutions.append(f"{r} -> {err}")

src/fromager/requirements_file.py

@@ -29,6 +29,9 @@ def __eq__(self, other: object) -> bool:
                 return self.value in allowed_values and other.value in allowed_values
         return super.__eq__(self, other)
 
+    def __ne__(self, value: object) -> bool:
+        return not self == value
+
 
 def parse_requirements_file(
     req_file: pathlib.Path,