Record origin url in wheel cache

src/pip/_internal/cache.py

@@ -5,12 +5,14 @@
 import json
 import logging
 import os
+from pathlib import Path
 from typing import Any, Dict, List, Optional, Set
 
 from pip._vendor.packaging.tags import Tag, interpreter_name, interpreter_version
 from pip._vendor.packaging.utils import canonicalize_name
 
 from pip._internal.exceptions import InvalidWheelFilename
+from pip._internal.models.direct_url import DirectUrl
 from pip._internal.models.format_control import FormatControl
 from pip._internal.models.link import Link
 from pip._internal.models.wheel import Wheel
@@ -19,6 +21,8 @@
 
 logger = logging.getLogger(__name__)
 
+ORIGIN_JSON_NAME = "origin.json"
+
 
 def _hash_dict(d: Dict[str, str]) -> str:
     """Return a stable sha224 of a dictionary."""
@@ -204,6 +208,10 @@ def __init__(
     ):
         self.link = link
         self.persistent = persistent
+        self.origin: Optional[DirectUrl] = None
+        origin_direct_url_path = Path(self.link.file_path).parent / ORIGIN_JSON_NAME
+        if origin_direct_url_path.exists():
+            self.origin = DirectUrl.from_json(origin_direct_url_path.read_text())
 
 
 class WheelCache(Cache):
@@ -262,3 +270,20 @@ def get_cache_entry(
             return CacheEntry(retval, persistent=False)
 
         return None
+
+    @staticmethod
+    def record_download_origin(cache_dir: str, download_info: DirectUrl) -> None:
+        origin_path = Path(cache_dir) / ORIGIN_JSON_NAME
+        if origin_path.is_file():
+            origin = DirectUrl.from_json(origin_path.read_text())
+            # TODO: use DirectUrl.equivalent when https://github.com/pypa/pip/pull/10564
+            # is merged.
+            if origin.url != download_info.url:
+                logger.warning(
+                    "Origin URL %s in cache entry %s does not match download URL %s. "
+                    "This is likely a pip bug or a cache corruption issue.",
+                    origin.url,
+                    cache_dir,
+                    download_info.url,
+                )
+        origin_path.write_text(download_info.to_json())

src/pip/_internal/resolution/legacy/resolver.py

@@ -431,6 +431,8 @@ def _populate_link(self, req: InstallRequirement) -> None:
             logger.debug("Using cached wheel link: %s", cache_entry.link)
             if req.link is req.original_link and cache_entry.persistent:
                 req.original_link_is_in_wheel_cache = True
+                if cache_entry.origin is not None:
+                    req.download_info = cache_entry.origin
             req.link = cache_entry.link
 
     def _get_dist_for(self, req: InstallRequirement) -> BaseDistribution:

src/pip/_internal/resolution/resolvelib/candidates.py

@@ -287,6 +287,8 @@ def __init__(
             and template.link is template.original_link
         ):
             ireq.original_link_is_in_wheel_cache = True
+            if cache_entry.origin is not None:
+                ireq.download_info = cache_entry.origin
 
         super().__init__(
             link=link,

src/pip/_internal/wheel_builder.py

@@ -354,6 +354,12 @@ def build(
                 req.editable and req.permit_editable_wheels,
             )
             if wheel_file:
+                # Record the download origin in the cache
+                if req.download_info is not None:
+                    # download_info is guaranteed to be set because when we build an
+                    # InstallRequirement it has been through the preparer before, but
+                    # let's be cautious.
+                    wheel_cache.record_download_origin(cache_dir, req.download_info)
                 # Update the link for this.
                 req.link = Link(path_to_url(wheel_file))
                 req.local_file_path = req.link.file_path