feat: Transform strings with respect to property schema when conforming properties

[ReubenFrankel]

Adds support for transforming string values to their defined property schema types.

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Related discussion: #2994
Closes #3014

Summary by Sourcery

Add automatic type conversion for string properties based on their schema during data conforming.

New Features:

• Transform string values to boolean, integer, number, array, or object types according to the property's JSON schema definition.
• Handle empty strings appropriately for each target type (e.g., 0 for integer/number, False for boolean, empty list/dict for array/object).
• Treat 'inf' and 'nan' strings as null when converting to numbers.
• Parse JSON strings when converting to array or object types.
• Perform case-insensitive matching for 'true' when converting to boolean; other strings become False.
• Return None for empty strings if the target schema is nullable and not string type itself

Tests:

• Add unit tests to cover various string transformation scenarios, including edge cases.

[sourcery-ai]

Reviewer's Guide by Sourcery

This pull request adds support for automatically transforming string values to the data type specified by a property's JSON schema during property conformance. This is achieved by introducing a new helper function that handles the conversion logic for various target types (boolean, integer, number, array, object) and integrating it into the existing property conformance function. Extensive test cases are added to cover different string inputs and target types.

No diagrams generated as the changes look simple and do not need a visual representation.

File-Level Changes

Change	Details	Files
Add new helper function to transform string properties to target types.	Add _transform_string_property function. Implement logic to convert strings to boolean, integer, number, array, and object. Handle empty string inputs based on the target type.	singer_sdk/helpers/_typing.py
Integrate string transformation into the primitive property conformance logic.	Modify _conform_primitive_property to check for string input and non-string schema. Call _transform_string_property when a string value needs conversion.	singer_sdk/helpers/_typing.py
Add comprehensive tests for string to type transformations.	Add new test cases to test_conform_primitives for string inputs to various types. Include tests for empty string handling. Add tests for case-insensitive boolean conversion. Add tests for JSON string parsing for array and object types.	tests/core/test_typing.py

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 91.70%. Comparing base (d7e844e) to head (97eed5a).

Additional details and impacted files

@@            Coverage Diff            @@
##           main    #2997       +/-   ##
=========================================
+ Coverage      0   91.70%   +91.70%     
=========================================
  Files         0       62       +62     
  Lines         0     5330     +5330     
  Branches      0      690      +690     
=========================================
+ Hits          0     4888     +4888     
- Misses        0      311      +311     
- Partials      0      131      +131     

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[codspeed-hq]

CodSpeed Performance Report

Merging #2997 will not alter performance

_{Comparing ReubenFrankel:feat/conform-primitive-interpret-string (97eed5a) with main (d7e844e)}

Summary

✅ 8 untouched benchmarks

[sourcery-ai]

Hey @ReubenFrankel - I've reviewed your changes - here's some feedback:

Overall Comments:

• Consider refactoring the _transform_string_property function to delegate type-specific transformations to smaller helper functions, improving clarity and maintainability.
• Define the expected behavior when a non-empty string cannot be successfully transformed into the target schema type (e.g., invalid JSON).

Here's what I looked at during the review

• 🟡 General issues: 2 issues found
• 🟢 Security: all looks good
• 🟡 Testing: 3 issues found
• 🟡 Complexity: 1 issue found
• 🟢 Documentation: all looks good

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[edgarrmondragon]

Thanks @ReubenFrankel!

My main concern with this would've been performance, but the benchmark seems unaffected? I could be missing something though.

[ReubenFrankel]

My main concern with this would've been performance, but the benchmark seems unaffected? I could be missing something though.

It looks like it was slightly affected: https://codspeed.io/meltano/sdk/branches/ReubenFrankel%3Afeat%2Fconform-primitive-interpret-string?uri=tests%2Fcore%2Ftest_typing.py%3A%3Atest_bench_conform_record_data_types

Possibly due to this new check, which will check the property schema type for every str value:

sdk/singer_sdk/helpers/_typing.py

Line 546 in 6c0f474

if isinstance(elem, str) and not is_string_type(property_schema):

[edgarrmondragon]

(commenting here to start a thread)

It looks like it was slightly affected: https://codspeed.io/meltano/sdk/branches/ReubenFrankel%3Afeat%2Fconform-primitive-interpret-string?uri=tests%2Fcore%2Ftest_typing.py%3A%3Atest_bench_conform_record_data_types

Possibly due to this new check, which will check the property schema type for every str value:

sdk/singer_sdk/helpers/_typing.py

Line 546 in 6c0f474

if isinstance(elem, str) and not is_string_type(property_schema):

Do you think there's a way we could prevent this regression? Perhaps caching a mapping of property > is_.

[ReubenFrankel]

Yes, I was thinking about some kind of type caching also. We did something like that here, or were you imagining it to be per-property?

[edgarrmondragon]

Yeah, something like or like the selection mask we use internally here.