Add version property to DurableOrchestrationContext class

[AnatoliB]

Add 'version' property to the context object passed to orchestrator functions.

As a result, Python Functions users will be able to specify a version in host.json:

{
  "extensions": {
    "durableTask": {
      "defaultVersion": "2.0"
    }
  }
}

and check the orchestration version in their orchestrator functions in order to keep them backward compatible, for example:

if (context.version == "1.0"):
    # Legacy code path
    activity_result = yield context.call_activity("A")
else:
    # New code path
    activity_result = yield context.call_activity("B")

Note: Microsoft.Azure.WebJobs.Extensions.DurableTask 3.1.0+ is required for this to work properly.

[Copilot]

Pull Request Overview

This PR introduces a version property on the DurableOrchestrationContext so orchestrator functions can detect their configured version, updates tests to cover this behavior, and adds a sample app showing how to use it.

• Extracts the first ExecutionStarted event’s version and exposes it via context.version.
• Adds unit tests to verify version detection and fallback to None.
• Provides a sample Function app and configuration demonstrating versioned orchestrations.

Reviewed Changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
tests/models/test_DurableOrchestrationContext.py	Added tests for extracting version from history events.
samples-v2/orchestration_versioning/requirements.txt	Added dependencies for the versioning sample.
samples-v2/orchestration_versioning/host.json	Configured "defaultVersion" under durableTask.
samples-v2/orchestration_versioning/function_app.py	Demonstrated branching logic on context.version.
azure/durable_functions/models/DurableOrchestrationContext.py	Implemented _version field, version property, and extraction.

Comments suppressed due to low confidence (1)

samples-v2/orchestration_versioning/function_app.py:5

• [nitpick] Variable myApp uses camelCase, which deviates from PEP8 snake_case conventions. Consider renaming to my_app or app for consistency.

myApp = df.DFApp(http_auth_level=func.AuthLevel.ANONYMOUS)