transplant: restore dirstate correctly at unexpected failure Before this patch, transplant can't restore dirstate as expected at failure other than one while patching. This causes: - unexpected file status - dirstate refers already rollback-ed parent (only at failure of transplanting the 2nd or later revision) To restore dirstate correctly also at unexpected failure, this patch encloses scope of store lock and transaction by 'dirstateguard'. This is temporary fixing for stable branch. See DirstateTransactionPlan wiki page for detail about the future plan to treat dirstate consistently around scope boundary of transaction. https://mercurial.selenic.com/wiki/DirstateTransactionPlan This patch also adds 'if lock' examination for safety 'lock.release()', because creating 'dirstateguard' object may fail unexpectedly (e.g. IOError for saving dirstate). BTW, in the test script, putting section header '[extensions]' into '.hg/hgrc' is needed to fix incomplete disabling 'abort' extension at 4d1382fd96ff.