Trace a render's reads through the hold set the test makes, dropping session.trace and repeatDepth

drawfence_test.go

@@ -62,7 +62,7 @@ func TestEveryReadARenderMakesIsGathered(t *testing.T) {
 	f := fenceCorpus(t)
 	roots, tables := fenceRoots(t, f)
 	for _, root := range roots {
-		wantGathered(t, f.rand, tables, root.label, renderDraws(root.t).reads, func() { renderRoot(f.rand, root.t) })
+		wantGathered(t, tables, root.label, renderDraws(root.t).reads, func(trace renderTrace) { renderRoot(f.rand, root.t, trace) })
 		if !root.t.isRecord || len(root.t.fields) == 0 {
 			continue
 		}
@@ -70,11 +70,11 @@ func TestEveryReadARenderMakesIsGathered(t *testing.T) {
 		if err != nil {
 			t.Fatalf("%s: recordOf = %v", root.label, err)
 		}
-		wantGathered(t, f.rand, tables, root.label+" as a record", columnDraws(root.t, sortedNames(root.t.fields)).reads, func() { renderRecordRoot(f.rand, root.t, columns) })
+		wantGathered(t, tables, root.label+" as a record", columnDraws(root.t, sortedNames(root.t.fields)).reads, func(trace renderTrace) { renderRecordRoot(f.rand, root.t, columns, trace) })
 	}
 }
 
-func wantGathered(t *testing.T, s *session, tables map[string]*table, label string, gathered []pathRead, renderOnce func()) {
+func wantGathered(t *testing.T, tables map[string]*table, label string, gathered []pathRead, renderOnce func(renderTrace)) {
 	t.Helper()
 	var reads []pathRead
 	type traceKey struct {
@@ -82,8 +82,8 @@ func wantGathered(t *testing.T, s *session, tables map[string]*table, label stri
 		row                int
 	}
 	seen := map[traceKey]bool{}
-	s.trace = &renderTrace{read: func(group, table string, row int, a arm) {
-		if s.trace.repeatDepth != 0 || !isRef(a.key) {
+	trace := func(group, table string, row int, a arm) {
+		if !isRef(a.key) {
 			return
 		}
 		r := pathRead{at: drawAt{group: group}, a: a}
@@ -94,10 +94,9 @@ func wantGathered(t *testing.T, s *session, tables map[string]*table, label stri
 			seen[k] = true
 			reads = append(reads, r)
 		}
-	}}
-	defer func() { s.trace = nil }()
+	}
 	for i := 0; i < 5; i++ {
-		renderOnce()
+		renderOnce(trace)
 	}
 	for _, r := range reads {
 		if !gathers(gathered, r) {
@@ -124,14 +123,14 @@ func spellPins(p *pinSet) string {
 	return "row " + strings.Join(rows, ", ")
 }
 
-func renderRoot(s *session, t *template) {
-	var set holdSet
+func renderRoot(s *session, t *template, trace renderTrace) {
+	set := holdSet{trace: trace}
 	sc := renderScope{set: &set}
 	switch {
 	case t.table != nil:
 		render(s, t.table, sc)
 		for r := 0; r < t.table.rowCount(); r++ {
-			var set holdSet
+			set := holdSet{trace: trace}
 			sc := renderScope{set: &set}
 			sc.groupHold().pins.pin(t.table, r)
 			render(s, t.table.pinnedRow, sc.at(t.table.pinnedRow, &sc.groupHold().pins))
@@ -143,8 +142,8 @@ func renderRoot(s *session, t *template) {
 	}
 }
 
-func renderRecordRoot(s *session, t *template, columns []Column) {
-	var set holdSet
+func renderRecordRoot(s *session, t *template, columns []Column, trace renderTrace) {
+	set := holdSet{trace: trace}
 	sc := renderScope{set: &set}
 	if t.table != nil {
 		t.table.drawIn(s, &sc.groupHold().pins)

fejkdata.go

@@ -45,7 +45,6 @@ type Generator struct {
 type session struct {
 	*rand.Rand
 	counters map[string]uint64
-	trace    *renderTrace
 }
 
 func (s *session) next(key string) uint64 {

hold.go

@@ -34,8 +34,8 @@ type readValue struct {
 // render's hold for its group, so its draw spans the render; every other held name in
 // held, the expansion's.
 func readField(s *session, t *template, held *hold, sc renderScope, a arm) readValue {
-	if s.trace != nil {
-		traceRead(s.trace, t, sc, a)
+	if sc.set.trace != nil {
+		traceRead(sc.set.trace, t, sc, a)
 	}
 	if !t.compiled.held[a.key] {
 		if len(a.tail) > 0 {
@@ -64,12 +64,9 @@ func readField(s *session, t *template, held *hold, sc renderScope, a arm) readV
 }
 
 // renderTrace is a test's view of the fields a render reads; nil outside a test.
-type renderTrace struct {
-	read        func(group, table string, row int, a arm)
-	repeatDepth int
-}
+type renderTrace func(group, table string, row int, a arm)
 
-func traceRead(trace *renderTrace, t *template, sc renderScope, a arm) {
+func traceRead(trace renderTrace, t *template, sc renderScope, a arm) {
 	var table string
 	var row int
 	switch {
@@ -78,7 +75,7 @@ func traceRead(trace *renderTrace, t *template, sc renderScope, a arm) {
 	case t.table != nil:
 		table, row = t.table.path, sc.rowOf(t.table)
 	}
-	trace.read(strings.Clone(sc.group), strings.Clone(table), row, a)
+	trace(strings.Clone(sc.group), strings.Clone(table), row, a)
 }
 
 // renderLeaf draws and renders what a read lands on: null on a null item, or on a column of one

holdset.go

@@ -5,10 +5,12 @@ import (
 	"strings"
 )
 
-// holdSet is one render's reference draws: the unnamed draw group's, and each named one's.
+// holdSet is one render's reference draws: the unnamed draw group's, and each named one's; and a
+// test's trace of its reads.
 type holdSet struct {
 	unnamed groupHold
 	named   map[string]*groupHold
+	trace   renderTrace
 }
 
 // renderScope is where a render reads its reference paths: a hold set, in the draw group of the
@@ -33,10 +35,6 @@ func renderOnce(s *session, n node) string {
 //go:noinline
 func expandAnew(s *session, t *template) string {
 	var set holdSet
-	if s.trace != nil {
-		s.trace.repeatDepth++
-		defer func() { s.trace.repeatDepth-- }()
-	}
 	return expand(s, t, renderScope{set: &set})
 }
 

todo.md

@@ -23,8 +23,6 @@ Shape 5.8, Self-sufficiency 5.7), every seat capped by Locality, all nine naming
 
 This round, in order:
 
-- Move `session.trace` and `renderTrace.repeatDepth` off the render path: they serve
-  `drawfence_test.go` alone.
 - Give `Fake` a local hold set like `FakeRecord`, `RecordTemplate.Fake` and
   `FakeStruct`, or state at `Generator.set` why it alone needs one: four seats read the
   field's heap claim as contradicted by the other three.