fix(gazelle): Fix the requirements arg to the gazelle python manifest generator. (#2533)

Fix args passed into the gazelle manifest file generator if the
requirements file is not a source file.

---------

Co-authored-by: Douglas Thor <[email protected]>

Author: sputt

CHANGELOG.md

@@ -4,7 +4,7 @@
 # rules_python Changelog
 
 This is a human-friendly changelog in a keepachangelog.com style format.
-Because this changelog is for end-user consumption of meaningful changes,only
+Because this changelog is for end-user consumption of meaningful changes, only
 a summary of a release's changes is described. This means every commit is not
 necessarily mentioned, and internal refactors or code cleanups are omitted
 unless they're particularly notable.
@@ -56,7 +56,7 @@ Unreleased changes template.
 
 {#v0-0-0-fixed}
 ### Fixed
-* Nothing fixed.
+* (gazelle) Providing multiple input requirements files to `gazelle_python_manifest` now works correctly.
 
 {#v0-0-0-added}
 ### Added

gazelle/manifest/defs.bzl

@@ -79,7 +79,7 @@ def gazelle_python_manifest(
 
     update_args = [
         "--manifest-generator-hash=$(execpath {})".format(manifest_generator_hash),
-        "--requirements=$(rootpath {})".format(requirements) if requirements else "--requirements=",
+        "--requirements=$(execpath {})".format(requirements) if requirements else "--requirements=",
         "--pip-repository-name={}".format(pip_repository_name),
         "--modules-mapping=$(execpath {})".format(modules_mapping),
         "--output=$(execpath {})".format(generated_manifest),