Create contribution plan_1

CONTRIBUTION_PLAN.md

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+## 1. Basic Information
+
+- **Project Name**: pandas  
+- **GitHub URL**: [https://github.com/pandas-dev/pandas](https://github.com/pandas-dev/pandas)
+
+- **Primary Language(s)**:  
+  - Python  
+  - C (some extensions)  
+  - Cython (for performance-critical code)
+
+- **What is the project used for?**  
+  `pandas` is a fast, powerful, and flexible open-source data analysis and manipulation library for Python. It provides high-level data structures such as `DataFrame` and `Series`, which are essential for working with structured data, time series, and large datasets in a convenient and efficient way.
+
+---
+
+## 2. Contribution Guidelines
+
+- **Are there clear steps in a `CONTRIBUTING.md` file?**  
+  ✅ No
+
+- **Is there a Code of Conduct?**  
+  ✅ Yes. The project includes a [Code of Conduct](https://github.com/pandas-dev/pandas/blob/main/CODE_OF_CONDUCT.md) to ensure respectful and inclusive participation.
+
+- **Is a CLA (Contributor License Agreement) needed?**  
+  ❌ No CLA is currently required for contributions to pandas.
+
+- **Are first-time contributors welcomed?**  
+  ✅ Yes. The project welcomes first-time contributors and provides good first issues with the `good first issue` label to help newcomers get started.
+
+---
+
+## 3. Environment Setup
+
+- **How do you set up the project locally?**
+
+```bash
+# Step 1: Clone your fork
+git clone https://github.com/<your-username>/pandas.git
+cd pandas
+
+# Step 2: Set up a virtual environment
+python -m venv venv
+source venv/bin/activate  # On Windows: venv\Scripts\activate
+
+# Step 3: Upgrade pip
+pip install --upgrade pip
+
+# Step 4: Install development dependencies
+pip install -r requirements-dev.txt
+
+# Step 5: Build the C extensions (optional but recommended)
+python setup.py build_ext --inplace
+
+# Step 6: Run tests to verify setup
+pytest pandas
+```
+
+
+
+## 4. Making a Contribution
+
+- **Open Issue Chosen:**  
+  [ENH: the error behaviour in pandas operation should be consistent – rename errors are ignore by default whereas drop errors are raise #61687](https://github.com/pandas-dev/pandas/issues/61687)
+
+- **Issue Summary:**  
+  In pandas, operations like `rename` silently ignore missing labels by default (unless `errors='raise'`), but operations like `drop` will raise an error for missing labels. This inconsistency in error-handling behavior is confusing. The feature request suggests making error behavior consistent across pandas APIs.
+
+### Steps to Resolve the Issue:
+1. Clarify API behavior by reviewing pandas functions (`rename`, `drop`, etc.) and documenting their default `errors` behavior.
+2. Decide on a consistent default approach—either always ignore or always raise—ideally matching common use cases or enhancing explicitness.
+3. Implement the change consistently:
+   - Modify default parameters or error-checking logic in `DataFrame.rename()`, `Series.rename()`, `drop()`, `set_index()`, etc.
+4. Update documentation in both docstrings and user guides to reflect the standardized behavior.
+5. Add unit tests in files like `pandas/tests/frame/test_rename_drop_errors.py`, covering:
+   - Missing labels with default behavior.
+   - Explicit use of `errors='ignore'` and `errors='raise'`.
+6. Validate changes by running `pytest pandas/tests/` and the full test suite.
+
+---
+
+## 5. Create a Pull Request Plan
+
+### Pull Request Workflow:
+
+1. Create a feature branch:
+   ```bash
+   git checkout -b standardize-errors-behavior
+   ```
+
+2. Make code changes in `pandas/core/generic.py`, potentially `indexing.py`, and documentation files.
+
+3. Stage and commit changes:
+   ```bash
+   git add pandas/core/generic.py pandas/core/indexing.py pandas/*.rst pandas/tests/frame/test_rename_drop_errors.py
+   git commit -m "ENH: Standardize default errors behavior across rename/drop (#61687)"
+   ```
+
+4. Push the branch to your fork:
+   ```bash
+   git push origin standardize-errors-behavior
+   ```
+
+5. Open a Pull Request:
+   - Base: `pandas-dev/pandas:main`
+   - Head: `yourusername/standardize-errors-behavior`
+
+---
+
+### Example PR Title:
+```
+ENH: Standardize default errors behavior across rename and drop (#61687)
+```
+
+---
+
+### PR Description:
+```
+This PR addresses [#61687](https://github.com/pandas-dev/pandas/issues/61687), which highlights an inconsistency in pandas default error handling: `rename()` silently ignores missing labels unless `errors='raise'` is specified, while methods like `drop()` raise errors for missing labels by default.
+
+### Changes:
+- Updated DataFrame/Series `rename()` to default to `errors='raise'` for consistency.
+- Updated documentation and docstrings to reflect this change.
+- Added unit tests to validate both default and explicit `errors` behavior for `rename` and `drop`.
+
+### Rationale:
+This enhances API consistency and helps avoid silent failures, making pandas operations more reliable.
+
+### Testing:
+- Tests covering missing-label scenarios with default/explicit `errors`.
+- Run:
+  ```bash
+  pytest pandas/tests/frame/test_rename_drop_errors.py
+  ```
+  Plus full suite with:
+  ```bash
+  pytest
+  ```
+```
+
+---
+
+### Testing the Fix
+
+- Run scoped tests:
+  ```bash
+  pytest pandas/tests/frame/test_rename_drop_errors.py
+  ```
+
+- Run full test suite:
+  ```bash
+  pytest
+  ```
+
+- Confirm that default errors behavior is consistent and that explicit usage of `errors='ignore'/'raise'` works correctly.