fix: set default Scope._transaction_info value to None

[andrewsapw]

In #1490, the ._transaction_info property was added to the Scope class. However, there are some issues with this property:

• It causes the error transaction_info: Discarded unknown attribute in older versions of the UI.
• There is inconsistency in how the field is handled. Although it is marked as Mapping[str, str], in some places (for example, here), it is checked against None.

This PR sets the default value of Scope._transaction_info to None.

[szokeasaurusrex]

@andrewsapw Could you please help me understand the problem you are experiencing?

It causes the error transaction_info: Discarded unknown attribute in older versions of the UI.

Regarding this error, could you please share a screenshot of the error message (or a link to the page, if you are using Sentry's SaaS offering)?

There is inconsistency in how the field is handled. Although it is marked as Mapping[str, str], in some places (for example, here), it is checked against None.

We can likely remove these checks against None, unless we can find somewhere where the field is set to None.

[andrewsapw]

@szokeasaurusrex of course! Screenshot of the error:

[szokeasaurusrex]

@andrewsapw Could you please also share a code snippet that reproduces this issue? And what version of Sentry self-hosted are you using?

[andrewsapw]

@szokeasaurusrex , example of code that reproduces this issue:

sentry_sdk.capture_message("[INFO] Test .capture_message", level="info")

Version of Sentry: 22.6.0 e68da5c