snapshot of https://github.com/mattermost/mattermost.git (master, 2026-09-16; blobs > 131072B omitted)

server/public/shared/markdown/inspect_test.go

@@ -0,0 +1,177 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See LICENSE.txt for license information.
+
+package markdown
+
+import (
+	"fmt"
+	"strings"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestInspect(t *testing.T) {
+	t.Run("base", func(t *testing.T) {
+		markdown := `
+[foo]: bar
+- a
+  > [![]()]()
+  > [![foo]][foo]
+- d
+`
+
+		visited := []string{}
+		level := 0
+		Inspect(markdown, func(blockOrInline any) bool {
+			if blockOrInline == nil {
+				level--
+			} else {
+				visited = append(visited, strings.Repeat(" ", level*4)+strings.TrimPrefix(fmt.Sprintf("%T", blockOrInline), "*markdown."))
+				level++
+			}
+			return true
+		})
+
+		assert.Equal(t, []string{
+			"Document",
+			"    Paragraph",
+			"    List",
+			"        ListItem",
+			"            Paragraph",
+			"                Text",
+			"            BlockQuote",
+			"                Paragraph",
+			"                    InlineLink",
+			"                        InlineImage",
+			"                    SoftLineBreak",
+			"                    ReferenceLink",
+			"                        ReferenceImage",
+			"                            Text",
+			"        ListItem",
+			"            Paragraph",
+			"                Text",
+		}, visited)
+	})
+
+	t.Run("visit nodes when len is smaller than maxLen", func(t *testing.T) {
+		n := MaxLen() / 5
+		markdown := strings.Repeat(`![`, n) + strings.Repeat(`]()`, n)
+
+		visited := []string{}
+		level := 0
+		Inspect(markdown, func(blockOrInline any) bool {
+			if blockOrInline == nil {
+				level--
+			} else {
+				visited = append(visited, strings.Repeat(" ", level*4)+strings.TrimPrefix(fmt.Sprintf("%T", blockOrInline), "*markdown."))
+				level++
+			}
+			return true
+		})
+
+		assert.NotEmpty(t, visited)
+	})
+
+	t.Run("do not visit any nodes when len is greater than maxLen", func(t *testing.T) {
+		n := (MaxLen() / 5) + 1
+		markdown := strings.Repeat(`![`, n) + strings.Repeat(`]()`, n)
+
+		visited := []string{}
+		level := 0
+		Inspect(markdown, func(blockOrInline any) bool {
+			if blockOrInline == nil {
+				level--
+			} else {
+				visited = append(visited, strings.Repeat(" ", level*4)+strings.TrimPrefix(fmt.Sprintf("%T", blockOrInline), "*markdown."))
+				level++
+			}
+			return true
+		})
+
+		assert.Empty(t, visited)
+	})
+
+	t.Run("a deeply nested single-line block quote is bounded rather than fully descended", func(t *testing.T) {
+		n := 20000
+		markdown := strings.Repeat("> ", n) + "x"
+
+		blockQuoteCount := 0
+		Inspect(markdown, func(blockOrInline any) bool {
+			if _, ok := blockOrInline.(*BlockQuote); ok {
+				blockQuoteCount++
+			}
+			return true
+		})
+
+		assert.Equal(t, maxNestingDepth-1, blockQuoteCount)
+	})
+
+	t.Run("a deeply nested single-line list is bounded rather than fully descended", func(t *testing.T) {
+		n := 20000
+		markdown := strings.Repeat("- ", n) + "x"
+
+		listCount := 0
+		Inspect(markdown, func(blockOrInline any) bool {
+			if _, ok := blockOrInline.(*List); ok {
+				listCount++
+			}
+			return true
+		})
+
+		assert.Equal(t, maxNestingDepth-1, listCount)
+	})
+}
+
+var counterSink int
+
+func BenchmarkInspect(b *testing.B) {
+	text := `Some standard piece of text.
+
+Has a link [post](https://github.com) and also has a blockquote.
+
+> This is a famous quote.
+
+Some bold text **Text for markdown?** to go with it.
+
+At the end, some more lines`
+
+	for b.Loop() {
+		Inspect(text, func(_ any) bool {
+			counterSink++
+			return true
+		})
+	}
+}
+
+// BenchmarkInspectNestedBlockQuote and BenchmarkInspectNestedList measure the cost of parsing a
+// single line made up of repeated block-quote/list markers. These benchmarks should scale roughly
+// linearly with input size (i.e. per-op time should stay flat as the marker count grows), since the
+// number of nested blocks actually created is capped at maxNestingDepth regardless of input size.
+func BenchmarkInspectNestedBlockQuote(b *testing.B) {
+	for _, n := range []int{1_000, 10_000, 60_000} {
+		markdown := strings.Repeat("> ", n) + "x"
+		b.Run(fmt.Sprintf("n=%d", n), func(b *testing.B) {
+			for b.Loop() {
+				Inspect(markdown, func(_ any) bool {
+					counterSink++
+					return true
+				})
+			}
+		})
+	}
+}
+
+func BenchmarkInspectNestedList(b *testing.B) {
+	for _, n := range []int{1_000, 10_000, 60_000} {
+		markdown := strings.Repeat("- ", n) + "x"
+		b.Run(fmt.Sprintf("n=%d", n), func(b *testing.B) {
+			for b.Loop() {
+				Inspect(markdown, func(_ any) bool {
+					counterSink++
+					return true
+				})
+			}
+		})
+	}
+}