Merge bitcoin/bitcoin#26828: assumeutxo: catch and log fs::remove error instead of two exist checks

0e21b56 assumeutxo: catch and log fs::remove error instead of two exist checks (Andrew Toth)

Pull request description:

  Fixes a block of code which seems to be incorrectly performing two existence checks instead of catching and logging errors. `fs::remove` returns `false` only if the file being removed does not exist, so it is redundant with the `fs::exists` check. If an error does occur when trying to remove an existing file, `fs::remove` will throw. See https://en.cppreference.com/w/cpp/filesystem/remove.

  Also see https://github.com/bitcoin/bitcoin/blob/master/src/init.cpp#L326-L332 for a similar pattern.

ACKs for top commit:
  MarcoFalke:
    lgtm ACK 0e21b56
  jamesob:
    ACK bitcoin/bitcoin@0e21b56
  achow101:
    ACK 0e21b56

Tree-SHA512: 137d0be5266cfd947e5e50ec93b895ac659adadf9413bef3468744bfdacee8dbe7d9bdfaf91784c45708610325d2241a114f4be4e622a108a639b3672b618fd2

Author: achow101

src/validation.cpp

@@ -4999,15 +4999,15 @@ static bool DeleteCoinsDBFromDisk(const fs::path db_path, bool is_snapshot)
     if (is_snapshot) {
         fs::path base_blockhash_path = db_path / node::SNAPSHOT_BLOCKHASH_FILENAME;
 
-        if (fs::exists(base_blockhash_path)) {
-            bool removed = fs::remove(base_blockhash_path);
-            if (!removed) {
-                LogPrintf("[snapshot] failed to remove file %s\n",
-                          fs::PathToString(base_blockhash_path));
+        try {
+            bool existed = fs::remove(base_blockhash_path);
+            if (!existed) {
+                LogPrintf("[snapshot] snapshot chainstate dir being removed lacks %s file\n",
+                          fs::PathToString(node::SNAPSHOT_BLOCKHASH_FILENAME));
             }
-        } else {
-            LogPrintf("[snapshot] snapshot chainstate dir being removed lacks %s file\n",
-                    fs::PathToString(node::SNAPSHOT_BLOCKHASH_FILENAME));
+        } catch (const fs::filesystem_error& e) {
+            LogPrintf("[snapshot] failed to remove file %s: %s\n",
+                    fs::PathToString(base_blockhash_path), fsbridge::get_filesystem_error_message(e));
         }
     }