d2sequence: fix sequence diagrams when appearing in child boards

ci/release/changelogs/next.md

@@ -17,6 +17,7 @@
 
 - Sequence diagram: multi-line edge labels no longer can collide with other elements [#2049](https://github.com/terrastruct/d2/pull/2049)
 - Sequence diagram: long self-referential edge labels no longer can collide neighboring actors (or its own) lifeline edges [#2050](https://github.com/terrastruct/d2/pull/2050)
+- Sequence diagram: fixes layout when sequence diagrams are in children boards (e.g. a layer) [#1692](https://github.com/terrastruct/d2/issues/1692)
 - Globs: An edge case was fixed where globs used in edges were creating nodes when it shouldn't have [#2051](https://github.com/terrastruct/d2/pull/2051)
 - Render: Multi-line class labels/headers are rendered correctly [#2057](https://github.com/terrastruct/d2/pull/2057)
 - CLI: Watch mode uses correct backlinks (`_` usages) [#2058](https://github.com/terrastruct/d2/pull/2058)

d2compiler/compile_test.go

@@ -2979,8 +2979,8 @@ qa: {
 			assertions: func(t *testing.T, g *d2graph.Graph) {
 				tassert.Equal(t, "dev.env", g.Objects[1].AbsID())
 				tassert.Equal(t, "Dev Environment", g.Objects[1].Label.Value)
-				tassert.Equal(t, "qa.env", g.Objects[2].AbsID())
-				tassert.Equal(t, "Qa Environment", g.Objects[2].Label.Value)
+				tassert.Equal(t, "qa.env", g.Objects[4].AbsID())
+				tassert.Equal(t, "Qa Environment", g.Objects[4].Label.Value)
 			},
 		},
 		{

d2graph/seqdiagram.go

@@ -1,6 +1,8 @@
 package d2graph
 
-import "oss.terrastruct.com/d2/d2target"
+import (
+	"oss.terrastruct.com/d2/d2target"
+)
 
 func (obj *Object) IsSequenceDiagram() bool {
 	return obj != nil && obj.Shape.Value == d2target.ShapeSequenceDiagram

d2ir/import.go

@@ -61,15 +61,18 @@ func (c *compiler) _import(imp *d2ast.Import) (Node, bool) {
 	if !ok {
 		return nil, false
 	}
-	nilScopeMap(ir)
 	if len(imp.IDA()) > 0 {
 		f := ir.GetField(imp.IDA()...)
 		if f == nil {
 			c.errorf(imp, "import key %q doesn't exist inside import", imp.IDA())
 			return nil, false
 		}
+		if f.Map() != nil {
+			nilScopeMap(f.Map())
+		}
 		return f, true
 	}
+	nilScopeMap(ir)
 	return ir, true
 }
 
@@ -132,15 +135,9 @@ func nilScopeMap(n Node) {
 		for _, r := range n.References {
 			r.Context_.ScopeMap = nil
 		}
-		if n.Map() != nil {
-			nilScopeMap(n.Map())
-		}
 	case *Field:
 		for _, r := range n.References {
 			r.Context_.ScopeMap = nil
 		}
-		if n.Map() != nil {
-			nilScopeMap(n.Map())
-		}
 	}
 }

d2layouts/d2sequence/sequence_diagram.go

@@ -1,9 +1,11 @@
 package d2sequence
 
 import (
+	"cmp"
 	"errors"
 	"fmt"
 	"math"
+	"slices"
 	"sort"
 	"strconv"
 	"strings"
@@ -76,6 +78,13 @@ func newSequenceDiagram(objects []*d2graph.Object, messages []*d2graph.Edge) (*s
 	var actors []*d2graph.Object
 	var groups []*d2graph.Object
 
+	slices.SortFunc(objects, func(a, b *d2graph.Object) int {
+		return cmp.Compare(getObjEarliestLineNum(a), getObjEarliestLineNum(b))
+	})
+	slices.SortFunc(messages, func(a, b *d2graph.Edge) int {
+		return cmp.Compare(getEdgeEarliestLineNum(a), getEdgeEarliestLineNum(b))
+	})
+
 	for _, obj := range objects {
 		if obj.IsSequenceDiagramGroup() {
 			queue := []*d2graph.Object{obj}

e2etests-cli/main_test.go

@@ -94,6 +94,30 @@ func TestCLI_E2E(t *testing.T) {
 				assert.TestdataDir(t, filepath.Join(dir, "layer-link"))
 			},
 		},
+		{
+			name: "sequence-layer",
+			run: func(t *testing.T, ctx context.Context, dir string, env *xos.Env) {
+				writeFile(t, dir, "index.d2", `k; layers: { seq: @seq.d2 }`)
+				writeFile(t, dir, "seq.d2", `shape: sequence_diagram
+a: me
+b: github.com/terrastruct/d2
+
+a -> b: issue about a bug
+a."some note about the bug"
+
+if i'm right: {
+	a <- b: fix
+}
+
+if i'm wrong: {
+	a <- b: nah, intended
+}`)
+				err := runTestMain(t, ctx, dir, env, "index.d2")
+				assert.Success(t, err)
+
+				assert.TestdataDir(t, filepath.Join(dir, "index"))
+			},
+		},
 		{
 			// Skip the empty base board so the animation doesn't show blank for 1400ms
 			name: "empty-base",