Marked certain APIs deprecated

Author: Enmk

CMakeLists.txt

@@ -23,7 +23,8 @@ PROJECT (CLICKHOUSE-CLIENT)
         ENDIF ()
         SET (CMAKE_EXE_LINKER_FLAGS, "${CMAKE_EXE_LINKER_FLAGS} -lpthread")
         # -Wpedantic makes int128 support somewhat harder and less performant (by not allowing builtin __int128)
-        SET (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall -Wextra -Werror")
+        # -Wno-deprecated-declarations to produce less cluttered output when building library itself (`deprecated` attributes are for library users)
+        SET (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall -Wextra -Werror -Wno-deprecated-declarations")
     ENDIF ()
 
     INCLUDE_DIRECTORIES (.)

clickhouse/base/string_utils.h

@@ -8,6 +8,7 @@
 namespace clickhouse {
 
 template <typename T>
+[[deprecated("Not used by clickhosue-cpp itself, and will be removed in next major release (3.0) ")]]
 inline T FromString(const std::string& s) {
    std::istringstream iss(s);
    T result;
@@ -16,6 +17,7 @@ inline T FromString(const std::string& s) {
 }
 
 template <typename T>
+[[deprecated("Not used by clickhosue-cpp itself, and will be removed in next major release (3.0) ")]]
 inline T FromString(const StringView& s) {
    std::istringstream iss((std::string(s)));
    T result;

clickhouse/client.h

@@ -90,13 +90,13 @@ struct ClientOptions {
     DECLARE_FIELD(connection_recv_timeout, std::chrono::seconds, SetConnectionRecvTimeout, std::chrono::seconds(0));
     DECLARE_FIELD(connection_send_timeout, std::chrono::seconds, SetConnectionSendTimeout, std::chrono::seconds(0));
 
-    // TODO deprecate setting
     /** It helps to ease migration of the old codebases, which can't afford to switch
     * to using ColumnLowCardinalityT or ColumnLowCardinality directly,
     * but still want to benefit from smaller on-wire LowCardinality bandwidth footprint.
     *
     * @see LowCardinalitySerializationAdaptor, CreateColumnByType
     */
+    [[deprecated("Makes implementation of LC(X) harder and code uglier. Will be removed in next major release (3.0) ")]]
     DECLARE_FIELD(backward_compatibility_lowcardinality_as_wrapped_column, bool, SetBakcwardCompatibilityFeatureLowCardinalityAsWrappedColumn, true);
 
     /** Set max size data to compress if compression enabled.