App Config - Check Paged Based Etags

[mrm9084]

Description

Similar to #44247, but list_configuration_settings only returns the changed pages.

All SDK Contribution checklist:

• The pull request does not introduce [breaking changes]
• CHANGELOG is updated for new features, bug fixes or other significant changes.
• I have read the contribution guidelines.

General Guidelines and Best Practices

• Title of the pull request is clear and informative.
• There are a small number of commits, each of which have an informative message. This means that previously merged commits do not appear in the history of the PR. For more information on cleaning up the commits in your PR, see this page.

Testing Guidelines

• Pull request includes test coverage for the included changes.

[Copilot]

Pull request overview

This PR enhances the list_configuration_settings() method in Azure App Configuration SDK to support efficient monitoring of configuration changes using etag-based pagination. Instead of fetching all pages, only pages that have changed since the provided etags are returned, reducing unnecessary data transfer.

Key changes:

• Added match_conditions parameter to by_page() method for providing etags to check against
• Implemented custom page iterators that perform HTTP conditional requests using If-None-Match headers
• Updated tests to use the new etag-based change detection instead of manual HTTP requests

Reviewed changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 6 comments.

Show a summary per file

File	Description
CHANGELOG.md	Documents the new etags parameter (should be match_conditions) for the by_page() method
azure/appconfiguration/_models.py	Adds new classes ConfigurationSettingPaged, ConfigurationSettingPagedAsync, and etag-checking page iterators to support conditional page fetching
azure/appconfiguration/_azure_appconfiguration_client.py	Updates sync client to return ConfigurationSettingPaged instead of ItemPaged
azure/appconfiguration/aio/_azure_appconfiguration_client_async.py	Updates async client to return ConfigurationSettingPagedAsync instead of AsyncItemPaged
tests/test_azure_appconfiguration_client.py	Refactors test to use the new by_page(match_conditions=...) API instead of manual HTTP requests; changes from add_configuration_setting to set_configuration_setting
tests/test_azure_appconfiguration_client_async.py	Refactors async test to use the new by_page(match_conditions=...) API instead of manual HTTP requests

[Copilot]

[nitpick] While moving the super().init() call after setting instance variables is a valid pattern that avoids potential issues with accessing uninitialized attributes, this change was not mentioned in the PR description. The change appears to be a preventative fix rather than addressing a specific bug. Consider documenting why this reordering was necessary in the commit message or PR description for future reference.