add extra docs to the changelog and adjust a bit

Author: aignas

CHANGELOG.md

@@ -72,7 +72,11 @@ END_UNRELEASED_TEMPLATE
 * (pypi) `pipstar` flag has been flipped to be enabled by default, to turn it
   off use `RULES_PYTHON_ENABLE_PIPSTAR=0` environment variable. If you do, please
   add a comment to
-  [#2949](https://github.com/bazel-contrib/rules_python/issues/2949).
+  [#2949](https://github.com/bazel-contrib/rules_python/issues/2949). On `WORKSPACE`
+  you will see `whl_library` re-fetching if the list of packages in the 
+  `requirements.txt` file changes, to workaround this in cases where you are not
+  vendoring the requirements you can set
+  {obj}`pip_repository.use_hub_alias_dependencies` to `True`.
 
 {#v0-0-0-fixed}
 ### Fixed

python/private/pypi/generate_whl_library_build_bazel.bzl

@@ -85,13 +85,15 @@ def generate_whl_library_build_bazel(
         ]
         dep_template = kwargs.get("dep_template")
         packages = kwargs.pop("packages", [])
-        if kwargs.get("requires_dist"):
+        if not kwargs.get("requires_dist"):
+            # no deps, we can leave the extra loads out
+            pass
+        elif packages:
+            kwargs["include"] = render.list(packages)
+        else:
             packages_load = dep_template.format(name = "", target = "requirements.bzl")
-            if "_//" in packages_load:
-                kwargs["include"] = render.list(packages)
-            else:
-                loads.append("""load("{}", "{}")""".format(packages_load, "packages"))
-                kwargs["include"] = "packages"
+            loads.append("""load("{}", "{}")""".format(packages_load, "packages"))
+            kwargs["include"] = "packages"
 
     for arg in unsupported_args:
         if kwargs.get(arg):

python/private/pypi/whl_library.bzl

@@ -428,7 +428,7 @@ def _whl_library_impl(rctx):
             dep_template = rctx.attr.dep_template or "@{}{{name}}//:{{target}}".format(
                 rctx.attr.repo_prefix,
             ),
-            packages = rctx.attr.packages,
+            packages = rctx.attr.packages if rctx.attr.repo_prefix else [],
             entry_points = entry_points,
             metadata_name = metadata.name,
             metadata_version = metadata.version,