add submodule diff links

modules/git/commit_submodule_file.go

@@ -11,6 +11,8 @@ import (
 	"path"
 	"regexp"
 	"strings"
+
+	"code.gitea.io/gitea/modules/setting"
 )
 
 var scpSyntax = regexp.MustCompile(`^([a-zA-Z0-9_]+@)?([a-zA-Z0-9._-]+):(.*)$`)
@@ -101,8 +103,8 @@ func getRefURL(refURL, urlPrefix, repoFullName, sshDomain string) string {
 
 // RefURL guesses and returns reference URL.
 // FIXME: template passes AppURL as urlPrefix, it needs to figure out the correct approach (no hard-coded AppURL anymore)
-func (sf *CommitSubModuleFile) RefURL(urlPrefix, repoFullName, sshDomain string) string {
-	return getRefURL(sf.refURL, urlPrefix, repoFullName, sshDomain)
+func (sf *CommitSubModuleFile) RefURL(repoFullName string) string {
+	return getRefURL(sf.refURL, setting.AppURL, repoFullName, setting.SSH.Domain)
 }
 
 // RefID returns reference ID.

options/locale/locale_en-US.ini

@@ -2627,6 +2627,9 @@ diff.image.overlay = Overlay
 diff.has_escaped = This line has hidden Unicode characters
 diff.show_file_tree = Show file tree
 diff.hide_file_tree = Hide file tree
+diff.submodule_added = Submodule %s added at %s
+diff.submodule_deleted = Submodule %s deleted from %s
+diff.submodule_updated = Submodule %s updated from %s to %s
 
 releases.desc = Track project versions and downloads.
 release.releases = Releases

routers/web/repo/view.go

@@ -309,7 +309,6 @@ func renderDirectoryFiles(ctx *context.Context, timeout time.Duration) git.Entri
 	}
 
 	ctx.Data["TreeLink"] = treeLink
-	ctx.Data["SSHDomain"] = setting.SSH.Domain
 
 	return allEntries
 }

services/gitdiff/gitdiff.go

@@ -360,7 +360,6 @@ type DiffFile struct {
 	IsLFSFile                 bool
 	IsRenamed                 bool
 	IsAmbiguous               bool
-	IsSubmodule               bool
 	Sections                  []*DiffSection
 	IsIncomplete              bool
 	IsIncompleteLineTooLong   bool
@@ -372,6 +371,9 @@ type DiffFile struct {
 	Language                  string
 	Mode                      string
 	OldMode                   string
+
+	IsSubmodule   bool // if IsSubmodule==true, then there must be a SubmoduleInfo
+	SubmoduleInfo *SubmoduleInfo
 }
 
 // GetType returns type of diff file.
@@ -609,9 +611,8 @@ parsingLoop:
 				if strings.HasPrefix(line, "new mode ") {
 					curFile.Mode = prepareValue(line, "new mode ")
 				}
-
 				if strings.HasSuffix(line, " 160000\n") {
-					curFile.IsSubmodule = true
+					curFile.IsSubmodule, curFile.SubmoduleInfo = true, &SubmoduleInfo{}
 				}
 			case strings.HasPrefix(line, "rename from "):
 				curFile.IsRenamed = true
@@ -646,17 +647,17 @@ parsingLoop:
 					curFile.Mode = prepareValue(line, "new file mode ")
 				}
 				if strings.HasSuffix(line, " 160000\n") {
-					curFile.IsSubmodule = true
+					curFile.IsSubmodule, curFile.SubmoduleInfo = true, &SubmoduleInfo{}
 				}
 			case strings.HasPrefix(line, "deleted"):
 				curFile.Type = DiffFileDel
 				curFile.IsDeleted = true
 				if strings.HasSuffix(line, " 160000\n") {
-					curFile.IsSubmodule = true
+					curFile.IsSubmodule, curFile.SubmoduleInfo = true, &SubmoduleInfo{}
 				}
 			case strings.HasPrefix(line, "index"):
 				if strings.HasSuffix(line, " 160000\n") {
-					curFile.IsSubmodule = true
+					curFile.IsSubmodule, curFile.SubmoduleInfo = true, &SubmoduleInfo{}
 				}
 			case strings.HasPrefix(line, "similarity index 100%"):
 				curFile.Type = DiffFileRename
@@ -915,6 +916,13 @@ func parseHunks(ctx context.Context, curFile *DiffFile, maxLines, maxLineCharact
 				}
 			}
 			curSection.Lines = append(curSection.Lines, diffLine)
+
+			// Parse submodule additions
+			if curFile.SubmoduleInfo != nil {
+				if ref, found := bytes.CutPrefix(lineBytes, []byte("+Subproject commit ")); found {
+					curFile.SubmoduleInfo.NewRefID = string(bytes.TrimSpace(ref))
+				}
+			}
 		case '-':
 			curFileLinesCount++
 			curFile.Deletion++
@@ -936,6 +944,13 @@ func parseHunks(ctx context.Context, curFile *DiffFile, maxLines, maxLineCharact
 				lastLeftIdx = len(curSection.Lines)
 			}
 			curSection.Lines = append(curSection.Lines, diffLine)
+
+			// Parse submodule deletion
+			if curFile.SubmoduleInfo != nil {
+				if ref, found := bytes.CutPrefix(lineBytes, []byte("-Subproject commit ")); found {
+					curFile.SubmoduleInfo.PreviousRefID = string(bytes.TrimSpace(ref))
+				}
+			}
 		case ' ':
 			curFileLinesCount++
 			if maxLines > -1 && curFileLinesCount >= maxLines {
@@ -1195,6 +1210,14 @@ func GetDiff(ctx context.Context, gitRepo *git.Repository, opts *DiffOptions, fi
 			}
 		}
 
+		// Populate Submodule URLs
+		if diffFile.SubmoduleInfo != nil {
+			err := diffFile.SubmoduleInfo.PopulateURL(diffFile, beforeCommit, commit)
+			if err != nil {
+				return nil, err
+			}
+		}
+
 		if !isVendored.Has() {
 			isVendored = optional.Some(analyze.IsVendor(diffFile.Name))
 		}

services/gitdiff/submodule.go

@@ -0,0 +1,55 @@
+// Copyright 2025 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package gitdiff
+
+import "code.gitea.io/gitea/modules/git"
+
+type SubmoduleInfo struct {
+	SubmoduleURL  string
+	NewRefID      string
+	PreviousRefID string
+}
+
+func (si *SubmoduleInfo) PopulateURL(diffFile *DiffFile, leftCommit, rightCommit *git.Commit) error {
+	// If the submodule is removed, we need to check it at the left commit
+	if diffFile.IsDeleted {
+		if leftCommit == nil {
+			return nil
+		}
+
+		submodule, err := leftCommit.GetSubModule(diffFile.GetDiffFileName())
+		if err != nil {
+			return err
+		}
+
+		if submodule != nil {
+			si.SubmoduleURL = submodule.URL
+		}
+
+		return nil
+	}
+
+	// Even if the submodule path is updated, we check this at the right commit
+	submodule, err := rightCommit.GetSubModule(diffFile.Name)
+	if err != nil {
+		return err
+	}
+
+	if submodule != nil {
+		si.SubmoduleURL = submodule.URL
+	}
+	return nil
+}
+
+func (si *SubmoduleInfo) RefID() string {
+	if si.NewRefID != "" {
+		return si.NewRefID
+	}
+	return si.PreviousRefID
+}
+
+// RefURL guesses and returns reference URL.
+func (si *SubmoduleInfo) RefURL(repoFullName string) string {
+	return git.NewCommitSubModuleFile(si.SubmoduleURL, si.RefID()).RefURL(repoFullName)
+}