single merge: Avoid loops

If a symlink points to a directory already visited in parent path,
don't visit. Otherwise you will get a stack overflow.

1 files changed, 20 insertions, 13 deletions

diff --git a/libs/io/src/main/java/org/the_jk/cleversync/io/SingleMerge.kt b/libs/io/src/main/java/org/the_jk/cleversync/io/SingleMerge.kt
index 9869993..3fd73b4 100644
--- a/libs/io/src/main/java/org/the_jk/cleversync/io/SingleMerge.kt
+++ b/libs/io/src/main/java/org/the_jk/cleversync/io/SingleMerge.kt
@@ -5,7 +5,7 @@ import java.time.Instant
 
 object SingleMerge {
     fun calculate(target: Directory, source: Directory, options: Options = Options()): List<Action> {
-        return visit(target, source.list(), Context(source, options), "/")
+        return visit(target, source.list(), Context(source, options), "/", setOf(source))
     }
 
     private fun visit(
@@ -13,6 +13,7 @@ object SingleMerge {
         source: Directory.Content,
         context: Context,
         path: String,
+        visited: Set<Directory>,
     ) : List<Action> {
         val targetContent = target?.list()
         val targetNames = if (targetContent != null && context.options.deleteFilesOnlyInTarget) {
@@ -32,6 +33,7 @@ object SingleMerge {
                     this@buildList,
                     context,
                     path,
+                    visited union setOf(sourceDir),
                 )
             }
             source.files.forEach { sourceFile ->
@@ -40,7 +42,7 @@ object SingleMerge {
             }
             source.links.forEach { sourceLink ->
                 targetNames?.remove(sourceLink.name)
-                visitLink(targetContent, sourceLink, this@buildList, context, path)
+                visitLink(targetContent, sourceLink, this@buildList, context, path, visited)
             }
             targetNames?.forEach { (name, type) ->
                 when (type) {
@@ -60,13 +62,14 @@ object SingleMerge {
         actions: MutableList<Action>,
         context: Context,
         path: String,
+        visited: Set<Directory>,
     ) {
         val sourcePath = PathUtils.join(path, sourceName)
         if (targetContent == null) {
             actions.add(
                 Action.ChangeDir(
                     sourceName,
-                    visit(null, sourceContent, context, sourcePath),
+                    visit(null, sourceContent, context, sourcePath, visited),
                     create = true,
                 ),
             )
@@ -76,7 +79,7 @@ object SingleMerge {
                 actions.add(
                     Action.ChangeDir(
                         sourceName,
-                        visit(targetDir, sourceContent, context, sourcePath),
+                        visit(targetDir, sourceContent, context, sourcePath, visited),
                     ),
                 )
             } else {
@@ -88,7 +91,7 @@ object SingleMerge {
                 actions.add(
                     Action.ChangeDir(
                         sourceName,
-                        visit(null, sourceContent, context, sourcePath),
+                        visit(null, sourceContent, context, sourcePath, visited),
                         create = true,
                     ),
                 )
@@ -132,6 +135,7 @@ object SingleMerge {
         actions: MutableList<Action>,
         context: Context,
         path: String,
+        visited: Set<Directory>,
     ) {
         val linkTarget = sourceLink.resolve()
         if (!context.options.resolveLinks && insideRoot(context.root, path, linkTarget.path)) {
@@ -162,14 +166,17 @@ object SingleMerge {
         } else {
             when (linkTarget) {
                 is Link.DirectoryTarget -> {
-                    visitDir(
-                        targetContent,
-                        sourceLink.name,
-                        linkTarget.directory.list(),
-                        actions,
-                        context,
-                        path,
-                    )
+                    if (!visited.contains(linkTarget.directory)) {
+                        visitDir(
+                            targetContent,
+                            sourceLink.name,
+                            linkTarget.directory.list(),
+                            actions,
+                            context,
+                            path,
+                            visited union setOf(linkTarget.directory),
+                        )
+                    }
                 }
 
                 is Link.FileTarget -> {