Git: Fix handling of symlinks in tree artifacts

The introduction of non-upwards symlinks as first-class objects
should have updated the handling of known git tree artifacts
containing symlinks. In particular, one should consider trees in
their entirety when uploading (irrespective of the ignore_special
flag), and git trees should only be reported as known only if
the ignore_special flag is set to false.

1 files changed, 7 insertions, 5 deletions

diff --git a/src/buildtool/file_system/file_root.hpp b/src/buildtool/file_system/file_root.hpp
index b2768471..b332f9cd 100644
--- a/src/buildtool/file_system/file_root.hpp
+++ b/src/buildtool/file_system/file_root.hpp
@@ -213,8 +213,7 @@ class FileRoot {
         }
 
         /// \brief Retrieve a root tree as a KNOWN artifact.
-        /// User should know whether this root tree is symlink free and only
-        /// call this function accordingly.
+        /// Only succeeds if no entries have to be ignored.
         [[nodiscard]] auto AsKnownTree(std::string const& repository)
             const noexcept -> std::optional<ArtifactDescription> {
             if (Compatibility::IsCompatible()) {
@@ -223,6 +222,10 @@ class FileRoot {
             if (std::holds_alternative<tree_t>(data_)) {
                 try {
                     auto const& data = std::get<tree_t>(data_);
+                    // check if tree is ignore_special
+                    if (data->RawHash().empty()) {
+                        return std::nullopt;
+                    }
                     auto const& id = data->Hash();
                     auto const& size = data->Size();
                     if (size) {
@@ -502,11 +505,10 @@ class FileRoot {
     }
 
     /// \brief Read a root tree based on its ID.
-    /// User should know whether the desired tree is symlink free and only call
-    /// this function accordingly.
+    /// This should include all valid entry types.
     [[nodiscard]] auto ReadTree(std::string const& tree_id) const noexcept
         -> std::optional<GitTree> {
-        if (std::holds_alternative<git_root_t>(root_) and not ignore_special_) {
+        if (std::holds_alternative<git_root_t>(root_)) {
             try {
                 auto const& cas = std::get<git_root_t>(root_).cas;
                 return GitTree::Read(cas, tree_id);