Merge bitcoin/bitcoin#24470: Disallow more unsafe string->path conversions allowed by path append operators

f64aa9c411ad78259756a28756ec1eb8069b5ab4 Disallow more unsafe string->path conversions allowed by path append operators (Ryan Ofsky)

Pull request description:

  Add more `fs::path` `operator/` and `operator+` overloads to prevent unsafe string->path conversions on Windows that would cause strings to be decoded according to the current Windows locale & code page instead of the correct string encoding.

  Update application code to deal with loss of implicit string->path conversions by calling `fs::u8path` or `fs::PathFromString` explicitly, or by just changing variable types from `std::string` to `fs::path` to avoid conversions altogether, or make them happen earlier.

  In all cases, there's no change in behavior either (1) because strings only contained ASCII characters and would be decoded the same regardless of what encoding was used, or (2) because of the 1:1 mapping between paths and strings using the `PathToString` and `PathFromString` functions.

  Motivation for this PR was just that I was experimenting with #24469 and noticed that operations like `fs::path / std::string` were allowed, and I thought it would be better not to allow them.

ACKs for top commit:
  hebasto:
    ACK f64aa9c411ad78259756a28756ec1eb8069b5ab4

Tree-SHA512: 944cce49ed51537ee7a35ea4ea7f5feaf0c8fff2fa67ee81ec5adebfd3dcbaf41b73eb35e49973d5f852620367f13506fd12a7a9b5ae3a7a0007414d5c9df50f

1 files changed, 2 insertions, 2 deletions

diff --git a/src/validation.cpp b/src/validation.cpp
index e2eb6a1f7a..5a2bee2418 100644
--- a/src/validation.cpp
+++ b/src/validation.cpp
@@ -1491,7 +1491,7 @@ CAmount GetBlockSubsidy(int nHeight, const Consensus::Params& consensusParams)
 }
 
 CoinsViews::CoinsViews(
-    std::string ldb_name,
+    fs::path ldb_name,
     size_t cache_size_bytes,
     bool in_memory,
     bool should_wipe) : m_dbview(
@@ -1519,7 +1519,7 @@ void CChainState::InitCoinsDB(
     size_t cache_size_bytes,
     bool in_memory,
     bool should_wipe,
-    std::string leveldb_name)
+    fs::path leveldb_name)
 {
     if (m_from_snapshot_blockhash) {
         leveldb_name += "_" + m_from_snapshot_blockhash->ToString();