Don't redownload the component mapping file

bugbug/repository.py

@@ -854,6 +854,9 @@ def set_commits_to_ignore(repo_dir, commits):
 def download_component_mapping():
     global path_to_component
 
+    if path_to_component is not None:
+        return
+
     utils.download_check_etag(
         "https://firefox-ci-tc.services.mozilla.com/api/index/v1/task/gecko.v2.mozilla-central.latest.source.source-bugzilla-info/artifacts/public/components.json",
         "data/component_mapping.json",

tests/test_repository.py

@@ -328,6 +328,7 @@ def test_download_component_mapping():
     repository.download_component_mapping()
     assert len(repository.path_to_component) == 0
 
+    repository.path_to_component = None
     responses.reset()
     responses.add(
         responses.HEAD,
@@ -351,6 +352,13 @@ def test_download_component_mapping():
     assert repository.path_to_component["AUTHORS"] == "mozilla.org::Licensing"
     assert repository.path_to_component["Cargo.lock"] == "Firefox Build System::General"
 
+    responses.reset()
+    repository.download_component_mapping()
+    assert len(repository.path_to_component) == 2
+    assert repository.path_to_component["AUTHORS"] == "mozilla.org::Licensing"
+    assert repository.path_to_component["Cargo.lock"] == "Firefox Build System::General"
+
+    repository.path_to_component = None
     responses.reset()
     responses.add(
         responses.HEAD,