From 72a0d4b022b72a7f48a7784df04d50ec8bd874f5 Mon Sep 17 00:00:00 2001
From: John Ericson <John.Ericson@Obsidian.Systems>
Date: Tue, 7 May 2024 13:57:39 -0400
Subject: [PATCH] Try to fix macOS Nixpkgs lib test failure

Sometimes we read a directory with children we cannot stat. It's a pitty
we even try to stat at all (wasteful) in the `DT_UNKNOWN` case, but at
least this should get rid of the failure.
---
 src/libstore/unix/gc.cc              |  8 +++++++
 src/libutil/posix-source-accessor.cc | 31 ++++++++++++++++++++--------
 2 files changed, 30 insertions(+), 9 deletions(-)

diff --git a/src/libstore/unix/gc.cc b/src/libstore/unix/gc.cc
index c10ed5564..38cbf12b2 100644
--- a/src/libstore/unix/gc.cc
+++ b/src/libstore/unix/gc.cc
@@ -256,6 +256,14 @@ void LocalStore::findRoots(const Path & path, std::filesystem::file_type type, R
 
     }
 
+    catch (std::filesystem::filesystem_error & e) {
+        /* We only ignore permanent failures. */
+        if (e.code() == std::errc::permission_denied || e.code() == std::errc::no_such_file_or_directory || e.code() == std::errc::not_a_directory)
+            printInfo("cannot read potential root '%1%'", path);
+        else
+            throw;
+    }
+
     catch (SysError & e) {
         /* We only ignore permanent failures. */
         if (e.errNo == EACCES || e.errNo == ENOENT || e.errNo == ENOTDIR)
diff --git a/src/libutil/posix-source-accessor.cc b/src/libutil/posix-source-accessor.cc
index 4ff61f6bb..aa13f4c56 100644
--- a/src/libutil/posix-source-accessor.cc
+++ b/src/libutil/posix-source-accessor.cc
@@ -133,18 +133,31 @@ SourceAccessor::DirEntries PosixSourceAccessor::readDirectory(const CanonPath &
     assertNoSymlinks(path);
     DirEntries res;
     for (auto & entry : nix::readDirectory(makeAbsPath(path).string())) {
-        std::optional<Type> type;
-        // cannot exhaustively enumerate because implementation-specific
-        // additional file types are allowed.
+        auto type = [&]() -> std::optional<Type> {
+            std::filesystem::file_type nativeType;
+            try {
+                nativeType = entry.symlink_status().type();
+            } catch (std::filesystem::filesystem_error & e) {
+                // We cannot always stat the child. (Ideally there is no
+                // stat because the native directory entry has the type
+                // already, but this isn't always the case.)
+                if (e.code() == std::errc::permission_denied || e.code() == std::errc::operation_not_permitted)
+                    return std::nullopt;
+                else throw;
+            }
+
+            // cannot exhaustively enumerate because implementation-specific
+            // additional file types are allowed.
 #pragma GCC diagnostic push
 #pragma GCC diagnostic ignored "-Wswitch-enum"
-        switch (entry.symlink_status().type()) {
-        case std::filesystem::file_type::regular: type = Type::tRegular; break;
-        case std::filesystem::file_type::symlink: type = Type::tSymlink; break;
-        case std::filesystem::file_type::directory: type = Type::tDirectory; break;
-        default: type = tMisc;
-        }
+            switch (nativeType) {
+            case std::filesystem::file_type::regular: return Type::tRegular; break;
+            case std::filesystem::file_type::symlink: return Type::tSymlink; break;
+            case std::filesystem::file_type::directory: return Type::tDirectory; break;
+            default: return tMisc;
+            }
 #pragma GCC diagnostic pop
+        }();
         res.emplace(entry.path().filename().string(), type);
     }
     return res;