[CONTRIB] Promote ExpectColumnValuesToMatchStrftimeFormat to supported-core by nanjeshramesh · Pull Request #12009 · fivetran/great_expectations

nanjeshramesh · 2026-07-28T08:47:57Z

Summary

Closes #12004.

ExpectColumnValuesToMatchStrftimeFormat already existed and was exported, but wasn't in the Expectation Gallery, had no generated schema, carried none of the support metadata, and had an undefined backend matrix. This brings it up to the supported-core bar:

Fixes a docstring bug: the old docstring contained the literal, never-interpolated token {FAILURE_SEVERITY_DESCRIPTION}. Converted to an __doc__ = f"""...""" f-string in the standard Gallery format (short description, Args, Supported Data Sources, Data Quality Issues, Example Data, passing/failing Code Examples), following the ExpectColumnValuesToMatchRegex exemplar.
Adds Gallery support metadata: EXPECTATION_SHORT_DESCRIPTION, DATA_QUALITY_ISSUES, SUPPORTED_DATA_SOURCES, a library_metadata ClassVar with _library_metadata alias, and Config.schema_extra.
Adds the class to supported_expectations in tasks.py and generates great_expectations/expectations/core/schemas/ExpectColumnValuesToMatchStrftimeFormat.json via invoke schemas --sync.

Backend matrix decision: shipping outcome (A) from the issue — Pandas + Spark supported, SQL explicitly declared out of scope. The backing metric (column_values_match_strftime_format.py) has no SqlAlchemy branch, and generic strftime-format validation doesn't map cleanly onto SQL dialects' date-format models (as noted in the issue, with precedent in ExpectColumnValuesToMatchRegex, which also omits some SQL dialects). Happy to follow up with a SQL implementation (outcome B) separately if maintainers want it split out.

Changes

great_expectations/expectations/core/expect_column_values_to_match_strftime_format.py — Gallery-format docstring, support metadata, schema config
great_expectations/expectations/core/schemas/ExpectColumnValuesToMatchStrftimeFormat.json — generated schema (new file)
tasks.py — added to supported_expectations
tests/integration/data_sources_and_expectations/expectations/test_expect_column_values_to_match_strftime_format.py — extended from Spark-only to also cover Pandas, plus added mostly-threshold success/failure cases

Test plan

ruff check / ruff format --check pass on all changed files
pytest tests/expectations/core/test_core_model_schemas.py passes (schema-sync check)
pytest tests/expectations/ -m unit — 1498 passed, 0 failed
Full pytest tests/ -m unit — 4330 passed, 0 failed
New integration tests pass locally against Pandas (-m "not spark"): timezone-aware format success (regression test for Validating datetime strings with timezone produces an error #9203), non-matching format failure, mostly-threshold met/not-met
Spark integration tests require pyspark, which isn't installed in my local dev environment — these are unchanged in logic from the existing Spark-only test and should run in maintainer CI

Brings the expectation up to the Gallery-supported bar: fixes the broken docstring (the FAILURE_SEVERITY_DESCRIPTION token was never interpolated), adds Gallery support metadata and a generated JSON schema, and declares Pandas + Spark as the supported backend matrix (SQL is out of scope for now, per the discussion in the issue - strftime tokens don't map cleanly onto SQL dialects' date-format models). Extends the integration tests to cover Pandas alongside the existing Spark cases, plus mostly-threshold coverage. Closes fivetran#12004 Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

netlify · 2026-07-28T08:48:01Z

👷 Deploy request for niobium-lead-7998 pending review.

Visit the deploys page to approve it

Name	Link
🔨 Latest commit	`f026d35`

github-actions · 2026-07-28T08:48:32Z

All committers have signed the CLA. ✅

nanjeshramesh · 2026-07-28T08:51:57Z

@cla-bot check

joshua-stauffer

hey @nanjeshramesh, thanks for the PR! this looks great, I just have some notes for the docstring. The passing case which fails is the critical one, the other two are more nits, but would be nice to clean up while we're making changes.

Once those changes are in we'll get this merged. Thanks again!

joshua-stauffer · 2026-08-04T12:38:48Z

+                  }},
+                  "meta": {{}},
+                  "success": false
+                }}


This is labeled as a passing case, but success is (correctly) false. We could use the pattern in great_expectations/expectations/core/expect_column_values_to_match_regex.py and have the example data use two columns instead, then use one for the passing case and the other for the failing case.

the docstrings are rendered in the Expectations gallery, so we want one actual passing case, and one failing case.

joshua-stauffer · 2026-08-04T12:50:20Z

+
+        SQL data sources are not currently supported: strftime format tokens do not map cleanly \
+        onto the date-format models of SQL dialects.
+


the newline continuation here is likely to cause extra whitespace to be rendered. Can we remove it, and move this section up to the bottom of the Column Map Expectations are one of the most common types of Expectation. paragraph?

joshua-stauffer · 2026-08-04T12:56:03Z

        mostly (None or a float between 0 and 1): \
-            Successful if at least mostly fraction of values match the expectation. \
+            {MOSTLY_DESCRIPTION} \
            For more detail, see [mostly](https://docs.greatexpectations.io/docs/reference/expectations/standard_arguments/#mostly).


Can we append Default 1. to this line, like in great_expectations/expectations/core/expect_column_values_to_match_regex.py?

- Rework the Gallery Code Examples to use two columns (event_date / invalid_date), so the Passing Case genuinely passes (success: true) and the Failing Case genuinely fails, following the pattern in ExpectColumnValuesToMatchRegex. Both examples were run against the actual expectation to confirm the JSON output is accurate. - Move the SQL-unsupported caveat out of the indented Supported Data Sources block (where its line continuation rendered with extra whitespace) and onto the end of the introductory Column Map Expectations paragraph instead. - Append "Default 1." to the mostly parameter description, matching the regex exemplar. Regenerated the JSON schema to match the updated docstring. Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

My previous commit moved the SQL-unsupported sentence to the end of the intro paragraph but kept the backslash line-continuation between its two lines, reproducing the exact rendering issue that was flagged instead of fixing it. The surrounding sentences in that paragraph use plain lines with no continuation, so match that: each sentence is now its own line with no trailing backslash. Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

nanjeshramesh · 2026-08-04T21:36:25Z

Hey @joshua-stauffer, thanks for the review! Pushed fixes for all three:

Reworked the Passing/Failing Code Examples to use two columns (event_date / invalid_date), following the ExpectColumnValuesToMatchRegex pattern — the Passing Case now genuinely passes (success: true) and the Failing Case genuinely fails. Ran both against the actual expectation to confirm the JSON output is accurate.
Moved the SQL-unsupported caveat to the bottom of the intro paragraph and removed the line-continuation backslash so it renders as a plain sentence, consistent with the rest of that paragraph.
Appended "Default 1." to the mostly description.

Ready for another look whenever you get a chance. Thanks again!

joshua-stauffer

looks great, thanks @nanjeshramesh

github-actions Bot added the cla-not-signed https://github.com/fivetran/great_expectations/blob/develop/CLA.md label Jul 28, 2026

github-actions Bot added cla-signed and removed cla-not-signed https://github.com/fivetran/great_expectations/blob/develop/CLA.md labels Jul 28, 2026

joshua-stauffer changed the title ~~Promote ExpectColumnValuesToMatchStrftimeFormat to supported-core~~ [CONTRIB] Promote ExpectColumnValuesToMatchStrftimeFormat to supported-core Aug 3, 2026

joshua-stauffer requested changes Aug 4, 2026

View reviewed changes

joshua-stauffer mentioned this pull request Aug 4, 2026

Support strftime format expectation gallery metadata #12005

Closed

nanjeshramesh and others added 2 commits August 4, 2026 14:24

joshua-stauffer approved these changes Aug 5, 2026

View reviewed changes

joshua-stauffer enabled auto-merge August 5, 2026 16:02

joshua-stauffer added this pull request to the merge queue Aug 5, 2026

Merged via the queue into fivetran:develop with commit bdd9446 Aug 5, 2026
78 of 80 checks passed

Navigation Menu

Uh oh!

[CONTRIB] Promote ExpectColumnValuesToMatchStrftimeFormat to supported-core - #12009

[CONTRIB] Promote ExpectColumnValuesToMatchStrftimeFormat to supported-core#12009
joshua-stauffer merged 3 commits into
fivetran:developfrom
nanjeshramesh:promote-strftime-format-expectation

nanjeshramesh commented Jul 28, 2026 •

edited

Loading

Uh oh!

netlify Bot commented Jul 28, 2026 •

edited

Loading

Uh oh!

github-actions Bot commented Jul 28, 2026 •

edited

Loading

Uh oh!

nanjeshramesh commented Jul 28, 2026

Uh oh!

joshua-stauffer left a comment

Uh oh!

joshua-stauffer Aug 4, 2026

Uh oh!

joshua-stauffer Aug 4, 2026

Uh oh!

joshua-stauffer Aug 4, 2026

Uh oh!

joshua-stauffer Aug 4, 2026

Uh oh!

nanjeshramesh commented Aug 4, 2026

Uh oh!

joshua-stauffer left a comment

Uh oh!

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

2 participants


		SQL data sources are not currently supported: strftime format tokens do not map cleanly \
		onto the date-format models of SQL dialects.

Uh oh!

Conversation

nanjeshramesh commented Jul 28, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Summary

Changes

Test plan

Uh oh!

netlify Bot commented Jul 28, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

👷 Deploy request for niobium-lead-7998 pending review.

Uh oh!

github-actions Bot commented Jul 28, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

nanjeshramesh commented Jul 28, 2026

Uh oh!

joshua-stauffer left a comment

Choose a reason for hiding this comment

Uh oh!

joshua-stauffer Aug 4, 2026

Choose a reason for hiding this comment

Uh oh!

joshua-stauffer Aug 4, 2026

Choose a reason for hiding this comment

Uh oh!

joshua-stauffer Aug 4, 2026

Choose a reason for hiding this comment

Uh oh!

joshua-stauffer Aug 4, 2026

Choose a reason for hiding this comment

Uh oh!

nanjeshramesh commented Aug 4, 2026

Uh oh!

joshua-stauffer left a comment

Choose a reason for hiding this comment

Uh oh!

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

2 participants

nanjeshramesh commented Jul 28, 2026 •

edited

Loading

netlify Bot commented Jul 28, 2026 •

edited

Loading

github-actions Bot commented Jul 28, 2026 •

edited

Loading