- JOB_RESTART, /* if running stop, then start unconditionally */
- JOB_TRY_RESTART, /* if running stop and then start */
+ JOB_RESTART, /* If running, stop. Then start unconditionally. */
+
+ _JOB_TYPE_MAX_MERGING,
+
+ /* JOB_NOP can enter into a transaction, but as it won't pull in
+ * any dependencies, it won't have to merge with anything.
+ * job_install() avoids the problem of merging JOB_NOP too (it's
+ * special-cased, only merges with other JOB_NOPs). */
+ JOB_NOP = _JOB_TYPE_MAX_MERGING, /* do nothing */
+
+ _JOB_TYPE_MAX_IN_TRANSACTION,
+
+ /* JOB_TRY_RESTART can never appear in a transaction, because
+ * it always collapses into JOB_RESTART or JOB_NOP before entering.
+ * Thus we never need to merge it with anything. */
+ JOB_TRY_RESTART = _JOB_TYPE_MAX_IN_TRANSACTION, /* if running, stop and then start */
+
+ /* JOB_RELOAD_OR_START won't enter into a transaction and cannot result
+ * from transaction merging (there's no way for JOB_RELOAD and
+ * JOB_START to meet in one transaction). It can result from a merge
+ * during job installation, but then it will immediately collapse into
+ * one of the two simpler types. */
+ JOB_RELOAD_OR_START, /* if running, reload, otherwise start */