fix(repl): Allow .none in parentExpr

Pantograph/Library.lean

@@ -132,8 +132,9 @@ def goalPrint (state: GoalState) (rootExpr: Bool) (parentExprs: Bool) (goals: Bo
       pure .none
   let parentExprs? ← if parentExprs then
       .some <$> state.parentMVars.mapM λ parent => parent.withContext do
-        let val := state.getMVarEAssignment parent |>.get!
-        serializeExpression options (← instantiateAll val)
+        let val? := state.getMVarEAssignment parent
+        val?.mapM λ val => do
+          serializeExpression options (← instantiateAll val)
     else
       pure .none
   let goals ← if goals then

Pantograph/Protocol.lean

@@ -325,7 +325,7 @@ structure GoalPrintResult where
   -- The root expression
   root?: Option Expression := .none
   -- The filling expression of the parent goal
-  parentExprs?: Option (List Expression) := .none
+  parentExprs?: Option (List (Option Expression)) := .none
   goals: Array Goal := #[]
   extraMVars: Array Expression := #[]
 

Test/Integration.lean

@@ -91,7 +91,7 @@ def test_tactic : Test := do
   step "goal.print" ({ stateId := 1, parentExprs? := .some true, rootExpr? := .some true }: Protocol.GoalPrint)
    ({
      root? := .some { pp? := "fun x => ?m.11"},
-     parentExprs? := .some [{ pp? := .some "fun x => ?m.11" }],
+     parentExprs? := .some [.some { pp? := .some "fun x => ?m.11" }],
    }: Protocol.GoalPrintResult)
   step "goal.tactic" ({ stateId := 1, tactic? := .some "intro y" }: Protocol.GoalTactic)
    ({ nextStateId? := .some 2, goals? := #[goal2], }: Protocol.GoalTacticResult)