FIX: Handling Access token with class level variables and removing static defination

[subrata-ms]

Work Item / Issue Reference

AB#40420

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Summary

This pull request refactors the way temporary buffers are managed for setting connection attributes in the Connection class, improving memory safety and simplifying buffer handling. Instead of using static vectors to store temporary string and binary data, the code now uses member variables to hold these buffers directly within each Connection instance.

Buffer Management Refactor:

• Removed static vectors (wstr_buffers, buffers) for storing temporary wide string and binary buffers, eliminating the need for manual buffer growth management and cleanup. [1] [2] [3]
• Added member variables wstrStringBuffer and strBytesBuffer to the Connection class for managing temporary buffers per connection instance, improving encapsulation and memory safety.
• Updated all relevant buffer usage in setAttribute to use these new member variables, replacing references to static buffers with instance variables. [1] [2] [3]

Code Simplification:

• Removed unnecessary static buffer and related logic, such as buffer size limits and periodic cleanup, resulting in cleaner and more maintainable code. [1] [2] [3]

[Copilot]

Pull Request Overview

This PR addresses a memory accumulation issue in the Connection::setAttribute method by replacing static vectors that indefinitely stored attribute values with class-level buffers. The static vectors were unnecessary since attribute values only need to persist for the duration of the ODBC API call.

Key changes:

• Removed static std::vector<std::wstring> and std::vector<std::string> buffers that accumulated historical attribute values
• Introduced two class-level member variables (wstrStringBuffer and strBytesBuffer) to temporarily hold attribute data
• Removed buffer size management code (MAX_BUFFER_COUNT logic) that was previously needed to prevent unbounded growth

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 3 comments.

File	Description
mssql_python/pybind/connection/connection.h	Adds two class-level buffer member variables for storing string and byte attribute data
mssql_python/pybind/connection/connection.cpp	Replaces static vector buffers with class-level buffers and removes buffer management logic

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[subrata-ms]

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[sumitmsft]

Left a couple of comments.

[github-actions]

📊 Code Coverage Report

🔥 Diff Coverage 50%

🎯 Overall Coverage 77%

📈 Total Lines Covered: 4819 out of 6194 📁 Project: mssql-python

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Diff Coverage

Diff: main...HEAD, staged and unstaged changes

• mssql_python/pybind/connection/connection.cpp (50.0%): Missing lines 258-261

Summary

• Total: 8 lines
• Missing: 4 lines
• Coverage: 50%

mssql_python/pybind/connection/connection.cpp

Lines 254-265

  254     } else if (py::isinstance<py::bytes>(value) ||
  255                py::isinstance<py::bytearray>(value)) {
  256         try {
  257             std::string binary_data = value.cast<std::string>();
! 258             this->strBytesBuffer.clear();
! 259             this->strBytesBuffer = std::move(binary_data);
! 260             SQLPOINTER ptr = const_cast<char*>(this->strBytesBuffer.c_str());
! 261             SQLINTEGER length = static_cast<SQLINTEGER>(this->strBytesBuffer.size());
  262 
  263             SQLRETURN ret = SQLSetConnectAttr_ptr(_dbcHandle->get(),
  264                                                   attribute, ptr, length);
  265             if (!SQL_SUCCEEDED(ret)) {

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📋 Files Needing Attention

📉 Files with overall lowest coverage (click to expand)

mssql_python.helpers.py: 67.8%
mssql_python.pybind.ddbc_bindings.cpp: 70.7%
mssql_python.pybind.connection.connection.cpp: 75.9%
mssql_python.pybind.connection.connection_pool.cpp: 78.9%
mssql_python.ddbc_bindings.py: 79.6%
mssql_python.pybind.ddbc_bindings.h: 79.7%
mssql_python.auth.py: 87.1%
mssql_python.pooling.py: 87.7%
mssql_python.__init__.py: 90.9%
mssql_python.exceptions.py: 92.8%

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