// collectionInfo describes important features of a collection.
type collectionInfo struct {

	// explicitCreate, if non-nil, will cause the collection to be explicitly
	// Create~d (with the given value) before ensuring indexes.
	explicitCreate *mgo.CollectionInfo

	// indexes listed here will be EnsureIndex~ed before state is opened.
	indexes []mgo.Index

	// global collections will not have environment filtering applied. Non-
	// global collections will have both transactions and reads filtered by
	// relevant environment uuid.
	global bool

	// ignoreInsertRestrictions allows us to run transactions that insert
	// to this collection even while the environment is dying. It applies
	// only to non-global collections; it was essentially created for the
	// convenience of cleanupsC.
	ignoreInsertRestrictions bool

	// rawAccess collections can be safely accessed as a mongo.WriteCollection.
	// Direct database access to txn-aware collections is strongly discouraged:
	// merely writing directly to a field makes it impossible to use that field
	// with mgo/txn; in the worst case, document deletion can destroy critical
	// parts of the state distributed by mgo/txn, causing different runners to
	// choose different global transaction orderings; this can in turn cause
	// operations to be skipped.
	//
	// Short explanation follows: two different runners pick different -- but
	// overlapping -- "next" transactions; they each pick the same txn-id; the
	// first runner writes to an overlapping document and records the txn-id;
	// and then the second runner inspects that document, sees that the chosen
	// txn-id has already been applied, and <splat> skips that operation.
	//
	// Goodbye consistency. So please don't mix txn and non-txn writes without
	// very careful analysis; and then, please, just don't do it anyway. If you
	// need raw mgo, use a rawAccess collection.
	rawAccess bool
}