[giscebot]

Context

An sastre deploy --as-diff --reject against staging failed while applying an ERP pull request. The installed apply_pr 3.4.8 then raised an ASCII decoding error while handling Git output containing UTF-8 text, which hid the actual patch conflict. Its unconditional git stash pop restored pre-existing work over the partially applied diff and left the staging checkout dirty with rejected/partial files.

The UTF-8 diagnostic issue has already been addressed on current master by #189. This pull request closes the remaining operational gap: failed diff deployments must not leave their partial changes in the target checkout.

@abaena-gisce: Això m'ho vaig trobar quan em va petar per tenir accents al cos de la PR quan vaig correr el sastre a l'entorn de python 2 que per defecte no es UTF-8. I et deixa tot el repo brut i amb un estat inconsistent. Hauria de netejar sempre tot el que fa tant els fitxers modificats/creats/eliminats + els .rej. Si no per accident es poden arribar a pujar fitxers o canvis no desitjats. La implementació del giscebot no sé si és correcte això no ho he provat encara.

Changes

• Roll back a failed remote diff to the HEAD captured before git apply.
• Remove untracked files created by the failed diff before restoring the pre-deploy stash.
• Keep the stash untouched when rollback itself fails, avoiding a stash pop over an inconsistent checkout.
• Preserve the original application error as the deployment failure; rollback errors are reported separately.
• Document the failure and recovery guarantees for --as-diff deployments.

Regression coverage

• Unresolved --reject hunks no longer leave .rej files or partial changes.
• Pre-existing untracked work containing UTF-8 text is restored after rollback.
• A failed rollback keeps the stash and does not hide the original Git error.
• A failed commit is also rolled back to a clean checkout.

Validation

• Python 2.7: PYTHONPATH=. python -m unittest discover -s tests — 59 tests passed.
• Python 3.11: PYTHONPATH=. python -m unittest discover -s tests — 59 tests passed.
• git diff --check — clean.

Traceability

• ERP task: TASK-95718
• Incident observed while deploying gisce/erp#29405 to staging.
• Requested by: @abaena-gisce