[Logging] Fixes LogProperties and LogPropertyIgnore attributes to work if an object being logged resides in a different assembly than the logging method

[iliar-turdushev]

Fixes #6598 by removing the Conditional attribute from the definition of the LogProperties and LogPropertyIgnore attributes.

The Conditional attribute is the root cause of the bug. When a property is marked with the LogPropertyIgnore attribute, the associated metadata is excluded from the compiled assembly. As a result, the logging method’s code generator, which relies on reflection to determine whether a property should be logged, lacks the necessary information and ends up emitting the property regardless.

When the logging method and the object being logged are located in the same assembly, the behavior differs. In this case, the code generator does not rely on the compiled assembly and can access the metadata associated with the LogPropertyIgnore attribute directly. As a result, it correctly identifies which properties should be excluded from logging.

While there is a workaround, i.e. defining the CODE_GENERATION_ATTRIBUTES compilation symbol required by the Conditional attribute, it is better to fix the bug by removing the Conditional attribute. If a user forget to apply the workaround he/she risks leaking privacy or security sensitive data which could be stored in properties marked as LogPropertyIgnore.

Microsoft Reviewers: Open in CodeFlow

[Copilot]

Pull Request Overview

This PR fixes attribute visibility for LogProperties and LogPropertyIgnore by removing their Conditional annotations, ensuring metadata is emitted across assemblies, and adds a cross-assembly test scenario.

• Removed [Conditional("CODE_GENERATION_ATTRIBUTES")] from both attribute definitions to retain attribute metadata in compiled assemblies.
• Introduced a HelperLibrary (ObjectToLog/FieldToLog) and updated unit test projects to validate logging objects from a different assembly.
• Enhanced existing emitter tests and test classes to include a LogObjectFromAnotherAssembly scenario.

Reviewed Changes

Copilot reviewed 8 out of 10 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
test/Generators/Microsoft.Gen.Logging/Unit/Microsoft.Gen.Logging.Unit.Tests.csproj	Added project reference to HelperLibrary for cross-assembly testing.
test/Generators/Microsoft.Gen.Logging/Unit/EmitterTests.cs	Included ObjectToLog assembly in generator input assemblies.
test/Generators/Microsoft.Gen.Logging/TestClasses/LogPropertiesExtensions.cs	Added LogObjectFromAnotherAssembly test logging method.
test/Generators/Microsoft.Gen.Logging/HelperLibrary/ObjectToLog.cs	Created helper class with LogPropertyIgnore and nested LogProperties.
test/Generators/Microsoft.Gen.Logging/HelperLibrary/Microsoft.Gen.Logging.HelperLibrary.csproj	Defined the HelperLibrary project configuration.
test/Generators/Microsoft.Gen.Logging/HelperLibrary/FieldToLog.cs	Created helper FieldToLog class.
src/Libraries/Microsoft.Extensions.Telemetry.Abstractions/Logging/LogPropertyIgnoreAttribute.cs	Removed unused using System.Diagnostics; and Conditional attribute.
src/Libraries/Microsoft.Extensions.Telemetry.Abstractions/Logging/LogPropertiesAttribute.cs	Removed unused using System.Diagnostics; and Conditional attribute.

Comments suppressed due to low confidence (3)

test/Generators/Microsoft.Gen.Logging/TestClasses/LogPropertiesExtensions.cs:250

• A new test method LogObjectFromAnotherAssembly was added, but there’s no corresponding expected output or assertions for its generated code. Please update the expected generated output or add assertions to cover this test scenario.

        public static partial void LogObjectFromAnotherAssembly(ILogger logger, [LogProperties] ObjectToLog logObject);

test/Generators/Microsoft.Gen.Logging/Unit/Microsoft.Gen.Logging.Unit.Tests.csproj:23

• [nitpick] The indentation of this <ProjectReference> line does not match the surrounding entries. Align indentation with existing project references for consistency.

    <ProjectReference Include="..\HelperLibrary\Microsoft.Gen.Logging.HelperLibrary.csproj" />

test/Generators/Microsoft.Gen.Logging/TestClasses/LogPropertiesExtensions.cs:8

• [nitpick] This using directive is not sorted with the other using statements. Consider grouping and ordering system usings first, then external dependencies, with a blank line between groups.

using Microsoft.Gen.Logging.Test;

[eduherminio]

I wonder if similar behavior also affects to TagNameAttribute and TagProviderAttribute.

[iliar-turdushev]

I wonder if similar behavior also affects to TagNameAttribute and TagProviderAttribute.

Yes, it is similar. For the TagName and TagProvider I'm going to create a separate issue, because they currently have a bug which doesn't allow to use them with properties. At the moment, they can be used only with log method parameters. We'll fix both bugs in the separate issue.