Fix RSS with baseURL with sub dir when render hooks is enabled

Fixes #13332

hugolib/rss_test.go

@@ -96,3 +96,51 @@ Figure:
 
 	b.AssertFileContent("public/index.xml", "img src="http://example.com/images/sunset.jpg")
 }
+
+// Issue 13332.
+func TestRSSCanonifyURLsSubDir(t *testing.T) {
+	t.Parallel()
+
+	files := `
+-- hugo.toml --
+baseURL = 'https://example.org/subdir'
+disableKinds = ['section','sitemap','taxonomy','term']
+[markup.goldmark.renderHooks.image]
+enableDefault = true
+[markup.goldmark.renderHooks.link]
+enableDefault = true
+-- layouts/_default/_markup/render-image.html --
+{{- $u := urls.Parse .Destination -}}
+{{- $src := $u.String | relURL -}}
+<img srcset="{{ $src }}" src="{{ $src }} 2x">
+<img src="{{ $src }}">
+{{- /**/ -}}
+-- layouts/_default/home.html --
+{{ .Content }}|
+-- layouts/_default/single.html --
+{{ .Content }}|
+-- layouts/_default/rss.xml --
+{{ with site.GetPage "/s1/p2" }}
+  {{ .Content | transform.XMLEscape | safeHTML }}
+{{ end }}
+-- content/s1/p1.md --
+---
+title: p1
+---
+-- content/s1/p2/index.md --
+---
+title: p2
+---
+![alt](a.jpg)
+
+[p1](/s1/p1)
+-- content/s1/p2/a.jpg --
+`
+
+	b := Test(t, files)
+
+	b.AssertFileContent("public/index.xml", "https://example.org/subdir/s1/p1/")
+	b.AssertFileContent("public/index.xml",
+		"img src=&#34;https://example.org/subdir/a.jpg",
+		"img srcset=&#34;https://example.org/subdir/a.jpg&#34; src=&#34;https://example.org/subdir/a.jpg 2x")
+}