Issue: Bug -> Querying Experiment by Dataset Version Error

[tendev-eoghan]

Issue you'd like to raise.

When working on #1390 I came across the following bug.

listDatasetVersions returns versions with 6 digits to represent a fraction of a second.
e.g. 2025-01-09T14:42:18.364000+00:00

When calling listProjects passing in a datasetVersion https://github.com/langchain-ai/langsmith-sdk/pull/1391 sometimes the datasetVersion returned from listDatasetVersions will not match the one tagged to a value from listProjects.

This is because listProjects sometimes has the datasetVersion with only 3 digits to represent a fraction of a second.
e.g. 2025-01-09T14:42:18.364+00:00

This issue also presents itself in the langsmith UI portal when filtering experiments by dataset version.

Suggestion:

standardise dataset versions to 6 digits to represent a fraction of a second across all references to dataset version.

[tendev-eoghan]

With some further digging I found this function which I think might be the root cause.

langsmith-sdk/js/src/evaluation/_runner.ts

Line 816 in 843d55d

// Python might return microseconds, which we need

Sometimes evaluation experiments are tagged with a dataset version using 3 digits of precision instead of 6.

[tendev-eoghan]

Issue fixed with the above PR by @tendev-liam

#1406

[tendev-liam]

PR #1406 does not completly solve this issue.

It appears if the dataset version timestamp ends in a zero the problem still persists.

e.g An expirment will gets its dataset version tagged as
2025-01-13T13:48:12.64721+00:00
Missing one zero in fractional seconds

however the getDatasetVersions api will respond with the timestamp like:
2025-01-13T13:48:12.647210+00:00