Fix streaming backoff logic flaws in retry module

[Copilot]

The retry logic in the streaming backoff implementation had three critical flaws that caused incorrect behavior during rate limiting scenarios:

Issues Fixed

1. Logger attempt count stuck at 1
The attempt number in log messages was calculated using options.max_attempts - max_attempts + 1, but since options.max_attempts always referenced the original value while max_attempts decreased, the calculation remained constant at 1 for all retry attempts.

2. Incorrect exponential backoff delays
The exponential delay calculation used base_delay * (2 ** (options.max_attempts - max_attempts)), which resulted in non-exponential delays like 0.13s → 0.29s → 0.20s instead of the expected exponential progression.

3. Logger names growing with recursive calls
Each recursive retry call created a new RetryOptions with logger.getChild("@teams/retry"), causing nested logger names like parent.@teams/retry.@teams/retry.@teams/retry.

Solution

• Added attempt_number parameter to RetryOptions to properly track the current attempt number
• Fixed exponential delay calculation to use base_delay * (2 ** (attempt_number - 1)) for true exponential backoff (0.5s → 1.0s → 2.0s → 4.0s)
• Added _internal_logger parameter to pass the existing child logger between recursive calls, preventing nested logger names
• Enhanced test coverage with comprehensive tests validating all three fixes

Before/After Example

# Before: Incorrect delays and attempt numbers
# Delaying 0.13s before retry (attempt 1)...
# Delaying 0.29s before retry (attempt 1)...
# Delaying 0.20s before retry (attempt 1)...

# After: Correct exponential backoff and attempt tracking
# Delaying 0.50s before retry (attempt 1)...
# Delaying 1.00s before retry (attempt 2)...  
# Delaying 2.00s before retry (attempt 3)...

This ensures proper rate limit handling in streaming scenarios where Microsoft Teams API calls need reliable exponential backoff.

Fixes #145.

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[Copilot]

Pull Request Overview

This PR fixes critical flaws in the streaming backoff retry logic that caused incorrect attempt counting, non-exponential delays, and nested logger names during recursive retry calls.

• Fixed attempt number calculation to properly increment from 1 instead of staying constant
• Corrected exponential backoff formula to use attempt_number - 1 for true exponential progression
• Prevented logger name nesting by passing existing child logger through recursive calls

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
packages/apps/src/microsoft/teams/apps/utils/retry.py	Added attempt_number and _internal_logger parameters, fixed exponential delay calculation and logger passing
packages/apps/tests/test_retry.py	Added comprehensive test suite covering attempt counting, exponential backoff, and logger behavior

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[MehakBindra]

Looks good, thanks Aamir !