Warning printed when using rails_semantic_logger's hash-based log_tags

[lucthev]

After upgrading to 1.13.0, I'm seeing a (false) warning in an app using rails_semantic_logger and its somewhat unusual hash-based log_tags:

W, [2023-07-31T17:56:28.916763 #71347]  WARN -- ddtrace: [ddtrace] Unable to add Datadog Trace context to ActiveSupport::TaggedLogging: NoMethodError undefined method `<<' for {:ip=>:remote_ip}:Hash

Coming from this code, which understandably fails when log_tags is a hash:

dd-trace-rb/lib/datadog/tracing/contrib/rails/log_injection.rb

Line 13 in b3f3a0a

app.config.log_tags << proc { Tracing.log_correlation if Datadog.configuration.tracing.log_injection }

This method of log tag injection appears to be unnecessary when using rails_semantic_logger, as Datadog injects trace tags via other means, at the individual log level — despite the warning, logs produced by rails_semantic_logger have the correct dd trace tags.

Current behaviour

The above warning.

Expected behaviour

No warning.

Steps to reproduce

I've created a sample app to demonstrate the issue. The relevant bits are lucthev/ddtrace-log-warning-repro@5cf860b...main.

Simply run rails s and a warning should be printed.

[marcotc]

Thank you for the quick upgrade, and the detailed issue report, @lucthev!

Seems like a combination of configurations that can be common.

despite the warning, logs produced by rails_semantic_logger have the correct dd trace tags.

This is reassuring, we'll work on a fix shortly!

[marcotc]

Fix is done, will be released in the next version of ddtrace: #3022

We'll update this issue when the release is out.