fix: workaround for https://github.com/jlowin/fastmcp/issues/1377 #50
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
mayurinehate
approved these changes
Oct 10, 2025
Contributor
mayurinehate
left a comment
mayurinehate
left a comment
There was a problem hiding this comment.
LGTM
Thanks for taking care of this
Let us plan on item to allow higher pydantic version as well.
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
This PR fixes a critical compatibility issue where mcp-server-datahub versions 0.3.0+ fail to import with Pydantic 2.12+, raising
TypeError: cannot specify both default and default_factory. The root cause is a bug in fastmcp 2.10.5 (fixed in 2.11.2+) where the Settings class incorrectly specifies both default and default_factory for a field. As a temporary workaround, this PR pins Pydantic to<2.12to avoid triggering the bug while maintaining compatibility with existing code. A follow-up issue should be created to properly upgrade fastmcp to 2.11.2+ and remove this constraint, which will require testing the middleware API changes and updating affected code (see fastmcp issue #1377 and PR #1380).