Improve fatal error message.

tddb/td/db/SqliteDb.cpp

@@ -76,7 +76,9 @@ Status SqliteDb::init(CSlice path, bool allow_creation) {
   auto database_stat = stat(path);
   if (database_stat.is_error()) {
     if (!allow_creation) {
-      LOG(FATAL) << "Database was deleted during execution and can't be recreated: " << database_stat.error();
+      bool was_destroyed = detail::RawSqliteDb::was_any_database_destroyed();
+      auto reason = was_destroyed ? Slice("was corrupted and deleted") : Slice("disappeared");
+      LOG(FATAL) << "Database " << reason << " during execution and can't be recreated: " << database_stat.error();
     }
     TRY_STATUS(destroy(path));
   }

tddb/td/db/SqliteDb.h

@@ -63,8 +63,6 @@ class SqliteDb {
   static Result<SqliteDb> change_key(CSlice path, bool allow_creation, const DbKey &new_db_key,
                                      const DbKey &old_db_key);
 
-  Status last_error();
-
   sqlite3 *get_native() const {
     return raw_->db();
   }

tddb/td/db/detail/RawSqliteDb.cpp

@@ -14,9 +14,13 @@
 #include "td/utils/port/path.h"
 #include "td/utils/port/Stat.h"
 
+#include <atomic>
+
 namespace td {
 namespace detail {
 
+static std::atomic<bool> was_database_destroyed{false};
+
 Status RawSqliteDb::last_error(sqlite3 *db, CSlice path) {
   return Status::Error(PSLICE() << Slice(sqlite3_errmsg(db)) << " for database \"" << path << '"');
 }
@@ -36,12 +40,17 @@ Status RawSqliteDb::last_error() {
   //If database was corrupted, try to delete it.
   auto code = sqlite3_errcode(db_);
   if (code == SQLITE_CORRUPT) {
+    was_database_destroyed.store(true, std::memory_order_relaxed);
     destroy(path_).ignore();
   }
 
   return last_error(db_, path());
 }
 
+bool RawSqliteDb::was_any_database_destroyed() {
+  return was_database_destroyed.load(std::memory_order_relaxed);
+}
+
 RawSqliteDb::~RawSqliteDb() {
   auto rc = sqlite3_close(db_);
   LOG_IF(FATAL, rc != SQLITE_OK) << last_error(db_, path());

tddb/td/db/detail/RawSqliteDb.h

@@ -45,6 +45,8 @@ class RawSqliteDb {
   Status last_error();
   static Status last_error(sqlite3 *db, CSlice path);
 
+  static bool was_any_database_destroyed();
+
   bool on_begin() {
     begin_cnt_++;
     return begin_cnt_ == 1;