Replace JsonError and DynamicValueError with SchemaError

[jdegoes]

Summary

This PR unifies all error types under SchemaError, ensuring that when combining JsonSelection or DynamicValueSelection via ++, errors are properly aggregated instead of being lost.

Closes #868

Problem

When combining two selections that both contain errors using ++, the previous implementation would:

• For JsonError: Concatenate messages with ; separator, losing path info from the second error
• For DynamicValueError: Same string concatenation issue

Solution

Replace both JsonError and DynamicValueError with SchemaError, which already supports error aggregation via its ++ operator that maintains a list of Single errors.

Changes

SchemaError enhancements

• Add SchemaError.Message case class for simple message+path errors
• Add SchemaError.message(details, path) constructor
• Add SchemaError.apply(details) convenience constructor
• Add atField, atIndex, atKey, atCase methods that prepend paths to all errors
• Add remapSource helper for updating paths in error aggregation

JsonSelection & DynamicValueSelection

• Replace Either[JsonError, ...] with Either[SchemaError, ...]
• Replace Either[DynamicValueError, ...] with Either[SchemaError, ...]
• Update ++ operator to aggregate errors when both sides fail

Files deleted

• JsonError.scala - replaced by SchemaError
• DynamicValueError.scala - replaced by SchemaError
• DynamicValueErrorSpec.scala - replaced by SchemaErrorPathSpec.scala

Test updates

• Add SchemaErrorPathSpec with comprehensive tests for path methods
• Update all tests using JsonError/DynamicValueError to use SchemaError
• Add tests verifying error aggregation in ++ operator

Testing

• All tests pass with 100% statement coverage
• Tested on both Scala 3.3.7 and Scala 2.13.18

[Copilot]

Pull request overview

This PR unifies JSON and DynamicValue error handling under SchemaError, so that selection and decoding operations can aggregate multiple errors (with paths) instead of losing detail via string concatenation.

Changes:

• Replace JsonError/DynamicValueError with SchemaError across JSON and DynamicValue selection, navigation, and decoding APIs, including JsonSelection, DynamicValueSelection, Json, DynamicValue, and JsonDecoder.
• Extend SchemaError with message-based errors, path-prepend helpers (atField, atIndex, atKey, atCase), and a source-remapping helper so aggregated errors keep accurate paths.
• Update and extend tests: add SchemaErrorPathSpec, adapt JSON/DynamicValue selection specs to SchemaError, and add dedicated tests for error aggregation (++) and exception behavior, while removing the now-obsolete error classes and specs.

Reviewed changes

Copilot reviewed 14 out of 14 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
schema/shared/src/main/scala/zio/blocks/schema/json/JsonSelection.scala	Switches JsonSelection to Either[SchemaError, Vector[Json]] and updates combinators (including ++) and extraction methods to propagate and aggregate SchemaErrors.
schema/shared/src/main/scala/zio/blocks/schema/DynamicValueSelection.scala	Migrates DynamicValueSelection to Either[SchemaError, Chunk[DynamicValue]] and updates ++, type-directed extraction, and unsafe helpers to work with SchemaError aggregation.
schema/shared/src/main/scala/zio/blocks/schema/SchemaError.scala	Adds SchemaError.Message, convenience constructors (message, apply(String)), path-prepend methods for all aggregated errors, and a remapSource helper used by those methods.
schema/shared/src/main/scala/zio/blocks/schema/json/JsonDecoder.scala	Changes all decoder signatures to return Either[SchemaError, A], threads SchemaError through collection and composite decoders, and forwards schema-derived codec errors as SchemaError; note: in eitherDecoder, the Right-branch still tags errors with .atField("Left"), which mislabels the error path and should use "Right" instead.
schema/shared/src/main/scala/zio/blocks/schema/json/Json.scala	Replaces JsonError with SchemaError for navigation (get), path-based mutation (modifyOrFail, setOrFail, deleteOrFail, insertOrFail), folds, parses, and reconstruction helpers, ensuring codec errors are surfaced as SchemaError.
schema/shared/src/main/scala/zio/blocks/schema/DynamicValue.scala	Replaces DynamicValueError with SchemaError throughout navigation, path-based updates, folds, and KV reconstruction, using SchemaError.message(..., path) to record precise paths.
schema/shared/src/main/scala/zio/blocks/schema/json/JsonError.scala	Deleted; functionality is replaced by SchemaError.Message and the enriched SchemaError API.
schema/shared/src/main/scala/zio/blocks/schema/DynamicValueError.scala	Deleted; replaced by SchemaError.Message and unified SchemaError handling for DynamicValue operations.
schema/shared/src/test/scala/zio/blocks/schema/json/JsonSpec.scala	Updates tests from JsonError to SchemaError, adjusts path assertions to the new SchemaError shape, adds suites validating SchemaError exception behavior and ++ aggregation in the JSON context.
schema/shared/src/test/scala/zio/blocks/schema/json/JsonSelectionSpec.scala	Migrates selection tests to SchemaError, including new tests verifying ++ aggregates errors and that type-directed extraction methods (as, unwrap, unwrapAll) now use SchemaError.
schema/shared/src/test/scala/zio/blocks/schema/DynamicValueSelectionSpec.scala	Adapts DynamicValueSelection tests to SchemaError, adds coverage for error aggregation in ++, and keeps unsafe methods asserting that SchemaError is thrown.
schema/shared/src/test/scala/zio/blocks/schema/DynamicValueSpec.scala	Switches fold failure tests from DynamicValueError to SchemaError to match the new API.
schema/shared/src/test/scala/zio/blocks/schema/SchemaErrorPathSpec.scala	New spec comprehensively testing SchemaError message formatting, ++ aggregation, and path-prepend behavior (atField, atIndex, atKey, atCase) across single and aggregated errors.
schema/shared/src/test/scala/zio/blocks/schema/DynamicValueErrorSpec.scala	Removed; its coverage is replaced by SchemaErrorPathSpec and the DynamicValue/selection tests that now validate SchemaError behavior.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[Copilot]

In the eitherDecoder implementation, the error path for the Right-branch currently uses error.atField("Left"), which incorrectly attributes decoding failures under the Right key to the Left field. This will produce misleading error paths when decoding fails in the Right case. To keep error reporting accurate, the Right-branch should tag errors with the "Right" field name instead.

Suggested change

	case Left(error) => return new Left(error.atField("Left"))
	case Left(error) => return new Left(error.atField("Right"))