From 79f2b2feb84bd362b1dbb1395bb16e13c970262b Mon Sep 17 00:00:00 2001
From: zeripath <art27@cantab.net>
Date: Sun, 4 Jul 2021 10:26:04 +0100
Subject: [PATCH 1/2] Fix relative links in postprocessed images (#16334)

If a pre-post-processed file contains relative img tags these need to be updated
and joined correctly with the prefix. Finally, the node attributes need to be updated.

Fix #16308

Signed-off-by: Andrew Thornton <art27@cantab.net>
Co-authored-by: 6543 <6543@obermui.de>
---
 modules/markup/html.go      |  3 ++-
 modules/markup/html_test.go | 35 +++++++++++++++++++++++++++++++++++
 2 files changed, 37 insertions(+), 1 deletion(-)

diff --git a/modules/markup/html.go b/modules/markup/html.go
index 216a1f20a3ae3..7b9844bf7522a 100644
--- a/modules/markup/html.go
+++ b/modules/markup/html.go
@@ -401,7 +401,7 @@ func (ctx *postProcessCtx) visitNode(node *html.Node, visitText bool) {
 		}
 	case html.ElementNode:
 		if node.Data == "img" {
-			for _, attr := range node.Attr {
+			for i, attr := range node.Attr {
 				if attr.Key != "src" {
 					continue
 				}
@@ -414,6 +414,7 @@ func (ctx *postProcessCtx) visitNode(node *html.Node, visitText bool) {
 
 					attr.Val = util.URLJoin(prefix, attr.Val)
 				}
+				node.Attr[i] = attr
 			}
 		} else if node.Data == "a" {
 			visitText = false
diff --git a/modules/markup/html_test.go b/modules/markup/html_test.go
index 4d6344a720f2a..848c2a77e0026 100644
--- a/modules/markup/html_test.go
+++ b/modules/markup/html_test.go
@@ -384,6 +384,41 @@ func TestRender_ShortLinks(t *testing.T) {
 		`<p><a href="https://example.org" rel="nofollow">[[foobar]]</a></p>`)
 }
 
+func TestRender_RelativeImages(t *testing.T) {
+	setting.AppURL = AppURL
+	setting.AppSubURL = AppSubURL
+	tree := util.URLJoin(AppSubURL, "src", "master")
+
+	test := func(input, expected, expectedWiki string) {
+		buffer, err := markdown.RenderString(&RenderContext{
+			URLPrefix: tree,
+			Metas:     localMetas,
+		}, input)
+		assert.NoError(t, err)
+		assert.Equal(t, strings.TrimSpace(expected), strings.TrimSpace(buffer))
+		buffer, err = markdown.RenderString(&RenderContext{
+			URLPrefix: setting.AppSubURL,
+			Metas:     localMetas,
+			IsWiki:    true,
+		}, input)
+		assert.NoError(t, err)
+		assert.Equal(t, strings.TrimSpace(expectedWiki), strings.TrimSpace(buffer))
+	}
+
+	rawwiki := util.URLJoin(AppSubURL, "wiki", "raw")
+	mediatree := util.URLJoin(AppSubURL, "media", "master")
+
+	test(
+		`<img src="Link">`,
+		`<img src="`+util.URLJoin(mediatree, "Link")+`"/>`,
+		`<img src="`+util.URLJoin(rawwiki, "Link")+`"/>`)
+
+	test(
+		`<img src="./icon.png">`,
+		`<img src="`+util.URLJoin(mediatree, "icon.png")+`"/>`,
+		`<img src="`+util.URLJoin(rawwiki, "icon.png")+`"/>`)
+}
+
 func Test_ParseClusterFuzz(t *testing.T) {
 	setting.AppURL = AppURL
 	setting.AppSubURL = AppSubURL

From d9f5fb5abb77ee138b87dafa57574b5b856b0624 Mon Sep 17 00:00:00 2001
From: 6543 <6543@obermui.de>
Date: Sun, 4 Jul 2021 12:37:35 +0200
Subject: [PATCH 2/2] fix TestRender_RelativeImages

---
 modules/markup/html_test.go | 13 ++-----------
 1 file changed, 2 insertions(+), 11 deletions(-)

diff --git a/modules/markup/html_test.go b/modules/markup/html_test.go
index 848c2a77e0026..dddb3ade0d083 100644
--- a/modules/markup/html_test.go
+++ b/modules/markup/html_test.go
@@ -390,18 +390,9 @@ func TestRender_RelativeImages(t *testing.T) {
 	tree := util.URLJoin(AppSubURL, "src", "master")
 
 	test := func(input, expected, expectedWiki string) {
-		buffer, err := markdown.RenderString(&RenderContext{
-			URLPrefix: tree,
-			Metas:     localMetas,
-		}, input)
-		assert.NoError(t, err)
+		buffer := markdown.RenderString(input, tree, localMetas)
 		assert.Equal(t, strings.TrimSpace(expected), strings.TrimSpace(buffer))
-		buffer, err = markdown.RenderString(&RenderContext{
-			URLPrefix: setting.AppSubURL,
-			Metas:     localMetas,
-			IsWiki:    true,
-		}, input)
-		assert.NoError(t, err)
+		buffer = markdown.RenderWiki([]byte(input), setting.AppSubURL, localMetas)
 		assert.Equal(t, strings.TrimSpace(expectedWiki), strings.TrimSpace(buffer))
 	}