[BUG] Fix relative links on orgmode

- Backport of #2385
- For regular non-image nonvideo links, they should be made relative,
this was done against `r.Ctx.Links.Base`, but since 637451a45e, that
should instead be done by `SrcLink()` if there's branch information set
in the context, because branch and treepath information are no longer
set in `r.Ctx.Links.Base`.
- This is consistent with how #2166 _fixed_ relative links.
- Media is not affected, `TestRender_Media` test doesn't fail.
- Adds unit tests.
- Ref https://codeberg.org/Codeberg/Community/issues/1485

(cherry picked from commit a2442793d2)

modules/markup/orgmode/orgmode.go

@@ -147,11 +147,21 @@ func (r *Writer) resolveLink(node org.Node) string {
 	}
 	if len(link) > 0 && !markup.IsLinkStr(link) &&
 		link[0] != '#' && !strings.HasPrefix(link, mailto) {
-		base := r.Ctx.Links.Base
+
+		var base string
+		if r.Ctx.IsWiki {
+			base = r.Ctx.Links.WikiLink()
+		} else if r.Ctx.Links.HasBranchInfo() {
+			base = r.Ctx.Links.SrcLink()
+		} else {
+			base = r.Ctx.Links.Base
+		}
+
 		switch l.Kind() {
 		case "image", "video":
 			base = r.Ctx.Links.ResolveMediaLink(r.Ctx.IsWiki)
 		}
+
 		link = util.URLJoin(base, link)
 	}
 	return link

modules/markup/orgmode/orgmode_test.go

@@ -36,14 +36,58 @@ func TestRender_StandardLinks(t *testing.T) {
 		assert.Equal(t, strings.TrimSpace(expected), strings.TrimSpace(buffer))
 	}
 
-	googleRendered := "<p><a href=\"https://google.com/\" title=\"https://google.com/\">https://google.com/</a></p>"
+	// No BranchPath or TreePath set.
-	test("[[https://google.com/]]", googleRendered)
+	test("[[file:comfy][comfy]]",
+		`<p><a href="http://localhost:3000/gogits/gogs/comfy" title="comfy">comfy</a></p>`)
+
+	test("[[https://google.com/]]",
+		`<p><a href="https://google.com/" title="https://google.com/">https://google.com/</a></p>`)
 
 	lnk := util.URLJoin(AppSubURL, "WikiPage")
 	test("[[WikiPage][WikiPage]]",
 		"<p><a href=\""+lnk+"\" title=\"WikiPage\">WikiPage</a></p>")
 }
 
+func TestRender_BaseLinks(t *testing.T) {
+	setting.AppURL = AppURL
+	setting.AppSubURL = AppSubURL
+
+	testBranch := func(input, expected string) {
+		buffer, err := RenderString(&markup.RenderContext{
+			Ctx: git.DefaultContext,
+			Links: markup.Links{
+				Base:       setting.AppSubURL,
+				BranchPath: "branch/main",
+			},
+		}, input)
+		assert.NoError(t, err)
+		assert.Equal(t, strings.TrimSpace(expected), strings.TrimSpace(buffer))
+	}
+
+	testBranchTree := func(input, expected string) {
+		buffer, err := RenderString(&markup.RenderContext{
+			Ctx: git.DefaultContext,
+			Links: markup.Links{
+				Base:       setting.AppSubURL,
+				BranchPath: "branch/main",
+				TreePath:   "deep/nested/folder",
+			},
+		}, input)
+		assert.NoError(t, err)
+		assert.Equal(t, strings.TrimSpace(expected), strings.TrimSpace(buffer))
+	}
+
+	testBranch("[[file:comfy][comfy]]",
+		`<p><a href="http://localhost:3000/gogits/gogs/src/branch/main/comfy" title="comfy">comfy</a></p>`)
+	testBranchTree("[[file:comfy][comfy]]",
+		`<p><a href="http://localhost:3000/gogits/gogs/src/branch/main/deep/nested/folder/comfy" title="comfy">comfy</a></p>`)
+
+	testBranch("[[file:./src][./src/]]",
+		`<p><a href="http://localhost:3000/gogits/gogs/src/branch/main/src" title="./src/">./src/</a></p>`)
+	testBranchTree("[[file:./src][./src/]]",
+		`<p><a href="http://localhost:3000/gogits/gogs/src/branch/main/deep/nested/folder/src" title="./src/">./src/</a></p>`)
+}
+
 func TestRender_Media(t *testing.T) {
 	setting.AppURL = AppURL
 	setting.AppSubURL = AppSubURL