Targeting a history state that is a direct child of a parallel state silently does nothing when that parallel state has not been visited yet and the history state has no default target. The machine stays in the source state instead of entering the parallel state's initial configuration, and no error is thrown.

const machine = createMachine({
  initial: 'off',
  states: {
    off: { on: { GO: 'on.hist' } },
    on: {
      type: 'parallel',
      states: {
        regA: { initial: 'a1', states: { a1: {}, a2: {} } },
        regB: { initial: 'b1', states: { b1: {}, b2: {} } },
        hist: { type: 'history', history: 'deep' }
      }
    }
  }
});

const actor = createActor(machine).start();
actor.send({ type: 'GO' });
actor.getSnapshot().value; // stays 'off'; expected { on: { regA: 'a1', regB: 'b1' } }

Cause

In resolveHistoryDefaultTransition (packages/core/src/stateUtils.ts), a history node with no configured target returns parent.initial. For a compound parent that is the single initial child, so entry works. For a parallel parent there is no single initial child, so parent.initial produces a transition with target: []; the empty target set flows through the entry machinery and the transition no-ops. The compound case is already documented and tested ("should execute actions of the initial transition when a history state without a default target is targeted and its parent state was never visited yet"); the parallel case was missed.

Fix

When the history node has no default target and its parent is a parallel state, return the parallel state itself as the target. The existing entry logic then enters every region at its initial state, which is the parallel state's initial configuration. Compound parents are unchanged.

Testing

Added deep and shallow history variants to packages/core/test/history.test.ts. They fail on the current code (value stays off) and pass with the fix. pnpm test:core stays green (1746 passed) and packages/core typechecks clean. Changeset included.