Merge bitcoin#24104: fs: Make compatible with boost 1.78

dc5d6b0 fs: Make compatible with boost 1.78 (Andrew Chow)

Pull request description:

  Boost 1.78 removed `operator+` in a way that breaks our usage of it in a subclass. A [proposed workaround](boostorg/filesystem#223 (comment)) for this is to cast the argument to `boost::filesystem::path`, and this is backwards compatible with older versions of boost.

  Additionally, it appears that `fs::canonical` no longer removes trailing slashes. This was causing a test to fail. The solution is to explicitly remove the trailing separator in the one place that `fs::canonical` is used.

  Lastly, `fs::create_directories` now has an error message saying `create_directories` instead of `create_directory`. This caused wallet_multiwallet.py to fail. The error message check has been updated to be able accept either string.

  Fixes bitcoin#23846

ACKs for top commit:
  ryanofsky:
    Code review ACK dc5d6b0
  vincenzopalazzo:
    ACK bitcoin@dc5d6b0

Tree-SHA512: d4d8e7b49b8dfbf0ced9bfe9a2b3827841227fc755fc799f19159076b0ccf882432cc8b6ad93cdeda98fb58b942b9ba50a9e0a6b4f6b1e0097e80f1074ae5682

Author: fanquake

src/fs.h

@@ -88,7 +88,7 @@ static inline auto quoted(const std::string& s)
 // Allow safe path append operations.
 static inline path operator+(path p1, path p2)
 {
-    p1 += std::move(p2);
+    p1 += static_cast<boost::filesystem::path&&>(p2);
     return p1;
 }
 

src/wallet/load.cpp

@@ -29,7 +29,7 @@ bool VerifyWallets(WalletContext& context)
         fs::path wallet_dir = fs::PathFromString(args.GetArg("-walletdir", ""));
         boost::system::error_code error;
         // The canonical path cleans the path, preventing >1 Berkeley environment instances for the same directory
-        fs::path canonical_wallet_dir = fs::canonical(wallet_dir, error);
+        fs::path canonical_wallet_dir = fs::canonical(wallet_dir, error).remove_trailing_separator();
         if (error || !fs::exists(wallet_dir)) {
             chain.initError(strprintf(_("Specified -walletdir \"%s\" does not exist"), fs::PathToString(wallet_dir)));
             return false;

test/functional/wallet_multiwallet.py

@@ -141,7 +141,7 @@ def wallet_file(name):
 
         # should raise rpc error if wallet path can't be created
         err_code = -4 if self.options.descriptors else -1
-        assert_raises_rpc_error(err_code, "boost::filesystem::create_directory:", self.nodes[0].createwallet, "w8/bad")
+        assert_raises_rpc_error(err_code, "boost::filesystem::create_director", self.nodes[0].createwallet, "w8/bad")
 
         # check that all requested wallets were created
         self.stop_node(0)