Backports of code older than the corpus: 19 of 4,006 OpenStack training examples are backports with no original in the corpus¶

backport-share.json (scripts/backport_share.py), metadata only. ROADMAP Plan H asked whether pre-cutoff code enters through cherry-picks: a change's window is its creation month, so a backport created inside the corpus can carry code first written before the checkpoint. A backport that keeps its original's Change-Id can be traced, and the examples keep no branch, so each one is read two ways. When every change with its (project, Change-Id) sits on a release, maintenance or deployment branch (as the hosts name them, from OpenStack's stable/ and StarlingX's r/stx to MediaWiki's REL1_xx, fundraising/REL1_xx and deploy/wmf/), its original is not in the corpus and may predate it. When any does, it may be such a backport, whose original is in the corpus and postdates the checkpoint with it.

Every example matched a raw change. The first column is the traceable route for code older than the corpus, about one percent or less in every window; it is excluded in a sensitivity analysis rather than looked up line by line against every branch. It is not a ceiling: a revert, a re-proposal under a new Change-Id or a hand copy carries old code untraced, which only a line-level lookup would find. The second column is also a deduplication fact: up to 12% of an organization's examples share a Change-Id with a change on another branch, which the study's change-level grouping keeps on one side of every window boundary. An independent review widened the branch names (the first pattern missed deploy/wmf/, fundraising/REL, bugfix/ and r/stx) and corrected an earlier wording of the first column as an upper bound.