kj::Directory::list*() should return sorted lists to avoid non-determinism.

c++/src/kj/filesystem-disk.c++

@@ -34,6 +34,7 @@
 #include <stdlib.h>
 #include "vector.h"
 #include "miniposix.h"
+#include <algorithm>
 
 #if __linux__
 #include <linux/fs.h>
@@ -599,7 +600,8 @@ public:
     }
 
     KJ_DEFER(closedir(dir));
-    kj::Vector<Decay<decltype(func(instance<StringPtr>(), instance<FsNode::Type>()))>> entries;
+    typedef Decay<decltype(func(instance<StringPtr>(), instance<FsNode::Type>()))> Entry;
+    kj::Vector<Entry> entries;
 
     for (;;) {
       errno = 0;
@@ -634,7 +636,9 @@ public:
       }
     }
 
-    return entries.releaseAsArray();
+    auto result = entries.releaseAsArray();
+    std::sort(result.begin(), result.end());
+    return result;
   }
 
   Array<String> listNames() {

c++/src/kj/filesystem.c++

@@ -1287,7 +1287,11 @@ private:
   };
 
   Clock& clock;
+
   std::map<StringPtr, EntryImpl> entries;
+  // Note: If this changes to a non-sorted map, listNames() and listEntries() must be updated to
+  //   sort their results.
+
   Date lastModified;
 
   template <typename T>

c++/src/kj/filesystem.h

@@ -426,6 +426,12 @@ public:
   struct Entry {
     FsNode::Type type;
     String name;
+
+    inline bool operator< (const Entry& other) const { return name <  other.name; }
+    inline bool operator> (const Entry& other) const { return name >  other.name; }
+    inline bool operator<=(const Entry& other) const { return name <= other.name; }
+    inline bool operator>=(const Entry& other) const { return name >= other.name; }
+    // Convenience comparison operators to sort entries by name.
   };
 
   virtual Array<Entry> listEntries() = 0;