Merge pull request #82 from SAY-5/fix-long-chain-index-panic

Author: AlexanderGrooff

cmd/graph.go

@@ -181,13 +181,10 @@ func (g *graph) setSubgraphs(textSubgraphs []*textSubgraph) {
 }
 
 func (g *graph) createMapping() {
-	// Set mapping coord for every node in the graph
-	highestPositionPerLevel := []int{}
-	// Init array with 0 values
-	// TODO: I'm sure there's a better way of doing this
-	for i := 0; i < 100; i++ {
-		highestPositionPerLevel = append(highestPositionPerLevel, 0)
-	}
+	// Set mapping coord for every node in the graph.
+	// Keyed by level so it grows with the graph instead of assuming a fixed
+	// number of levels; a missing key reads as the zero value.
+	highestPositionPerLevel := map[int]int{}
 
 	// TODO: should the mapping be bottom-to-top instead of top-to-bottom?
 	// Set root nodes to level 0

cmd/render_graph_test.go

@@ -1,13 +1,33 @@
 package cmd
 
 import (
+	"fmt"
 	"strings"
 	"testing"
 
 	"github.com/AlexanderGrooff/mermaid-ascii/pkg/diagram"
 	"github.com/mattn/go-runewidth"
 )
 
+func TestRenderGraphHandlesLongChainWithoutPanic(t *testing.T) {
+	config := diagram.NewTestConfig(true, "cli")
+
+	var b strings.Builder
+	b.WriteString("graph TD\n")
+	for i := 1; i < 30; i++ {
+		fmt.Fprintf(&b, "N%d --> N%d\n", i, i+1)
+	}
+
+	output, err := RenderDiagram(b.String(), config)
+	if err != nil {
+		t.Fatalf("RenderDiagram() error = %v", err)
+	}
+
+	if !strings.Contains(output, "N30") {
+		t.Fatalf("expected output to contain the last node\noutput:\n%s", output)
+	}
+}
+
 func TestRenderGraphKeepsDisplayWidthForWideNodeLabels(t *testing.T) {
 	config := diagram.NewTestConfig(true, "cli")
 	output, err := RenderDiagram("graph LR\nA[\"中A\"] --> B", config)