Update `swift-syntax`, fix Bool switch warnings, and improve test organization & coverage #150

qizh · 2025-11-27T14:42:08Z

This pull request updates dependencies, improves enum case encoding logic, enhances protocol constraints for numeric value coders, adds a new test for attribute misuse, and fixes compiler warnings. The changes focus on compatibility, correctness, improved diagnostics, and cleaner build output.

Dependency Updates

Updated swift-syntax dependency: Increased the upper bound to allow versions up to 603.0.0, ensuring compatibility with newer releases
Added^¹ SwiftSyntaxMacroExpansion: Explicit dependency added to PluginCore to resolve Xcode's dependency scanner warnings
📙¹ Dependency Addition Explanation & Reasoning

SwiftSyntaxMacroExpansion Dependency Addition

Problem Statement

Xcode's dependency scanner was generating warnings about implicit dependencies on the SwiftSyntaxMacroExpansion module. While the package compiled successfully, the implicit dependency meant that Xcode couldn't properly track the module dependency graph.

Root Cause

The MetaCodable package uses MacroExpansionContext and BasicMacroExpansionContext types from the SwiftSyntaxMacroExpansion module throughout the codebase, but this dependency was only declared implicitly through other swift-syntax modules. The Swift Package Manager resolved it transitively, but Xcode's dependency scanner requires explicit declarations for all directly-imported modules.

Solution
```
.product(name: "SwiftSyntaxMacroExpansion", package: "swift-syntax")
```
Should be added to the dependencies array for three targets:
1. ❇️ PluginCore (Package.swift:38, Package@swift-5.swift:37)
2. ☑️ MacroPlugin (already existed: Package.swift#L50)
3. ☑️ ProtocolGen (already existed: Package.swift#L64)
This makes the implicit dependency explicit, satisfying both the Swift Package Manager and Xcode's dependency scanner.

Usage Across the Codebase

1. Macro Expansion in PluginCore
- Codable+Expansion.swift: MacroExpansionContext parameter in the main expansion method
- Decodable+Expansion.swift: Context passed to create type variable representations
- EnumVariable.swift: Context stored for later code generation phases
- CodingKeysMap.swift: Context used to generate CodingKeys enum declarations
2. Protocol Code Generation in ProtocolGen
- Generate.swift: Direct import and usage of BasicMacroExpansionContext
- Used to generate helper coder implementations for protocols
- Creates context for both encoding and decoding code generation
3. Testing Infrastructure
- CodableTests.swift and ConformCodableTests.swift: Import module for macro expansion testing
- Used in assertMacroExpansion() test helper functions
- Required for verifying macro expansions produce correct code
Impact
- ✅ Resolves Xcode dependency scanner warnings
- ✅ Makes dependency graph explicit and traceable
- ✅ No functional changes to the codebase
- ✅ Maintains compatibility with both Swift 5.9 and Swift 6.0 manifests
- ✅ Aligns with Swift Package Manager best practices for explicit dependency declaration

Code Improvements

Enum encoding logic: Refactored enum case encoding in EnumVariable so cases without associated values are encoded as just the case name (without parentheses), improving generated code correctness
Bool switch warnings: Skip generating default case for Bool type switches since both true and false cases are explicitly handled, eliminating "default will never be executed" warnings

Protocol Enhancements

Sendable constraint: Added Sendable constraint to generic requirements for numeric value coding strategies, improving safety for concurrent use

Maintenance, Docs, Build Stability, Verification, and Backward-Compatible Refinements

Testing and Diagnostics

Attribute misuse test: Added new test case to ConformEncodableTests to check for misuse when @Codable is used with @ConformEncodable, providing better diagnostics for attribute conflicts
Test cleanup: Removed duplicate diagnostic expectations from ConformCodableTests.swift that were incorrectly preserved during merge conflict resolution

Documentation Updates

Inline documentation: Updated decodeSwitchExpression documentation to explain Bool type handling behavior
CHANGELOG: Added entry documenting the Bool switch warning fix

Build Configuration

Git ignore: Added *.dia files to .gitignore (Swift dependency analysis files, similar to .d and .o files)
Package configuration: Updated both Package.swift and Package@swift-5.swift to maintain Swift 5/6 compatibility

Verification

All tests pass without warnings
No warnings in command line build (swift build)
No warnings in Xcode build (MetaCodable-Package scheme)
Both Swift 5 and Swift 6 compatibility maintained

Context

The compiler warning fixes address issues that were particularly noticeable when:

Using @CodedAs with Bool raw values in enums
Building in Xcode with aggressive dependency scanning enabled

All changes maintain backward compatibility while providing cleaner build output for developers using MetaCodable.

Additional Changes (Jan 30, 2026)

🐛 Bug Fix Refinement

Fixed partial Bool coverage in TaggedEnumSwitcherVariable
- The original Bool switch fix incorrectly skipped the default case for ALL Bool switches
- Now correctly checks if both true and false values are present before skipping default case
- Fixes unreachable code warnings when only one Bool value is specified (e.g., @CodedAs<Bool>("isActive", ifTrue: SomeType.self))

🧪 Test Organization & Coverage

Coverage Improvements

Added tests for previously uncovered code paths:
- HelperCoder: decodeIfPresent, encode, encodeIfPresent
- ConditionalCoder: decodeIfPresent, encodeIfPresent
- DefaultSequenceElementCoding: optional encoding/decoding methods
- DynamicCodableIdentifier: CodingKey conformance methods
Added partial Bool coverage tests in CodedAsMixedTypesTests.swift

Test Suite Organization

Added @Suite declarations to all 50 test files for logical grouping
Replaced 565 unnamed @Test() with descriptive @Test("meaningful name")
Created Tags.swift with 30+ tag definitions for test filtering:
- Macro tags: .codable, .codedAt, .codedIn, .codedBy, etc.
- Test type tags: .macroExpansion, .encoding, .decoding, .errorHandling
- Feature tags: .helperCoders, .dynamicCoding, .generics
Reorganized tests into nested suites where appropriate
Added Tests/TODO/CoverageTracking.md for tracking coverage progress

🔧 CI/CD

Added .github/workflows/swift.yml for build and test automation
- Uses default Xcode toolchain on macos-latest
- Includes SwiftPM dependency caching
- Runs swift build and swift test --parallel --verbose

📝 Other

Added .markdownlint.json configuration

- [x] Bumped `swift-syntax` dependency to allow up to `603.0.0`. - [x] Added `SendableMetatype` constraint to `NumberCodingStrategy` extension. - [x] Refactored `caseEncodeExpr` in `EnumVariable` for consistent `FunctionCallExprSyntax` usage.

- [x] Corrected indentation for the `caseEncodeExpr` closure to maintain consistent formatting.

Copilot

Pull request overview

This PR updates the swift-syntax dependency to support versions up to 603.0.0 and addresses breaking API changes introduced in newer versions of the library.

Updated swift-syntax version range from "509.1.0"..<"602.0.0" to "509.1.0"..<"603.0.0"
Refactored FunctionCallExprSyntax initialization to use calledExpression: parameter instead of deprecated callee:
Added SendableMetatype constraint to ValueCodingStrategy extension for number types

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
Package.swift	Bumped swift-syntax dependency upper bound to 603.0.0
Sources/PluginCore/Variables/Type/EnumVariable.swift	Updated FunctionCallExprSyntax API usage from `callee:` to `calledExpression:` for consistency
Sources/HelperCoders/ValueCoders/Number.swift	Added SendableMetatype constraint to ValueCodingStrategy extension

Sources/HelperCoders/ValueCoders/Number.swift

Replaces the `SendableMetatype` constraint with `Sendable` in the `ValueCodingStrategy` extension to align with updated protocol requirements or type definitions.

- [x] Refactors `caseEncodeExpr` to return only the case name for enum cases without associated values, avoiding unnecessary parentheses. This improves code generation for enums with simple cases.

- [x] Update `ConformEncodableTests.misuseWithCodable` to expect four diagnostics. - [x] Ensure diagnostic IDs, messages, fix-its, and line/column positions match emitted results: - [x] Two diagnostics for `@ConformEncodable` at line 1, column 1. - [x] Two diagnostics for `@Codable` at line 2, column 1. - [x] Mirrors the pattern already used in `misuseWithDecodable`.

Copilot

Pull request overview

Copilot reviewed 4 out of 4 changed files in this pull request and generated 1 comment.

Tests/MetaCodableTests/ConformCodableTests.swift

paulgessinger · 2025-12-21T21:33:26Z

I'm very interested in this, because it currently keeps me on swift-syntax 601, which seems to cause issues with the (I think) newly bundled versions of this package with XCode.

This PR looks AI generated, but is there anything preventing this from proceeding?

qizh · 2025-12-22T08:48:59Z

This PR looks AI-generated.

Partially, it is.

I've made this update for myself, and I'm using my fork in production.
PR was made just in case someone will find it useful as well.

paulgessinger · 2025-12-22T09:37:23Z

@qizh It's been useful for me, so thanks for sharing!

soumyamahunt · 2026-01-19T19:03:55Z

Sorry for not responding to this earlier. Since the swift-syntax prebuilt bug: swiftlang/swift-package-manager#9240, this repo and the CI/CD for this was failing. I paused any kind of contribution till this is fixed.

This seems to be fixed now. @qizh can you rebase your PR?

#Conflicts: # Sources/PluginCore/Variables/Type/EnumVariable.swift # Tests/MetaCodableTests/ConformCodableTests.swift

Skip generating default case in switch statements when the header type is Bool, since both true and false cases are already explicitly handled. This eliminates "default will never be executed" compiler warnings in macro-generated code. - Update decodeSwitchExpression to check for Bool type before adding default - Update test expectation to match new behavior - Add inline documentation explaining the Bool type handling

Add explicit SwiftSyntaxMacroExpansion dependency to PluginCore target to resolve Xcode's dependency scanner warnings. The scanner detects that MacroExpansionContext (used extensively in PluginCore) requires this module as a transitive dependency. Applies to both Package.swift and Package@swift-5.swift for Swift 5/6 compatibility.

Add Swift dependency analysis files (*.dia) to gitignore as they are temporary build artifacts similar to .d and .o files.

Remove duplicate diagnostic test expectations that were incorrectly preserved during merge conflict resolution.

- [x] fix: resolve compiler warnings - [x] merge: from `upstream/main`

qizh · 2026-01-21T14:06:13Z

@qizh can you rebase your PR?

@soumyamahunt done

CHANGELOG.md

Package.swift

Package@swift-5.swift

Sources/PluginCore/Variables/Type/EnumVariable.swift

Sources/PluginCore/Variables/Enum/Switcher/TaggedEnumSwitcherVariable.swift

soumyamahunt · 2026-01-21T17:56:49Z

Thanks for updating this @qizh, please have a look on the comments when you can.

@suite

…iles Updated 50 test files to: - Add @suite declarations for logical grouping of tests - Replace unnamed @test() with @test("descriptive name") - Group related tests into nested suites where appropriate - Improve test organization and readability All tests continue to pass after the updates.

@codable

Updated all 565 tests across 50 files: - Analyzed actual test logic to generate descriptive names - Ensured all test names are unique across the entire test suite - Applied proper capitalization and English grammar - Preserved parameterized tests with arguments: - Replaced generic names like "expansion" with context-specific descriptions e.g., "Generates @codable conformance for struct with 'open' access" - Error tests now clearly state what error they verify e.g., "Reports error when @codingkeys is used without @codable" Test names now immediately communicate what each test verifies, making test failures instantly understandable without needing to inspect the test code. Updated Tests/TODO/CoverageTracking.md to document the test organization improvements.

@codable

Added Swift Testing tags to organize and filter the 529 tests: - Created Tags.swift with 30+ tag definitions covering: • Macro tags (@codable, @codedat, @codedin, etc.) • Test type tags (macroExpansion, encoding, decoding, errorHandling) • Feature tags (helperCoders, dynamicCoding, generics, etc.) • Type tags (structs, classes, enums, rawRepresentable) • Helper coder specific tags • Coverage tag for coverage-improvement tests - Tagged all 529 tests based on actual content analysis - Tags enable filtering tests by macro, feature, or test type - Example: @test("...", .tags(.codable, .macroExpansion, .structs)) Updated Tests/TODO/CoverageTracking.md with tagging documentation and usage examples. All 565 tests continue to pass with tags applied.

@test

Added multiline formatting for @test declarations with many tags: - Tests with many tags (>3) now use multiline format - Each tag on its own line for better readability - Applied to CodableTests and GenericsTests as examples - Format: @test( "Test name", .tags( .tag1, .tag2, .tag3 ) ) All 565 tests continue to pass.

- Add tests for partial Bool coverage in CodedAsMixedTypesTests.swift - Fix decodeSwitchExpression to only skip default case when both true and false Bool values are covered - Previously, default case was skipped for ALL Bool switches, causing unreachable code warnings when only one Bool value was specified The fix checks if both true and false are present in the enum cases before deciding to skip the default case in Bool switches.

- Add tests for partial Bool coverage in CodedAsMixedTypesTests.swift - Fix decodeSwitchExpression to only skip default case when both true and false Bool values are covered - Previously, default case was skipped for ALL Bool switches, causing unreachable code warnings when only one Bool value was specified The fix checks if both true and false are present in the enum cases before deciding to skip the default case in Bool switches. (cherry picked from commit bb8f9a5)

Remove leftover merge conflict markers (`<<<<<<< HEAD, =======, >>>>>>>`) from the test file that were accidentally committed during the previous merge.

This workflow will be disabled on GitHub.

@qizh

With another badge @qizh is interested in

Tests/MetaCodableTests/CodedAs/CodedAsMixedTypesTests.swift

Sources/PluginCore/Variables/Type/EnumVariable.swift

@codable

Swift 6.2.1 has a bug causing fatalError during ExpandSynthesizedMemberMacroRequest when processing @codable macro on protocols (ExtPost in PostPage.swift)

Swift 6.1/6.2 from swift-actions has compiler crash during macro expansion. Default Xcode toolchain on macos-latest should be more stable.

Improve test coverage and organization

Tests/MetaCodableTests/HelperCoders/LossySequenceTests.swift

Tests/MetaCodableTests/CodableTests.swift

Tests/MetaCodableTests/ConditionalCoderTests.swift

Tests/MetaCodableTests/DefaultSequenceElementCodingTests.swift

Tests/MetaCodableTests/DynamicCodableIdentifierTests.swift

Tests/MetaCodableTests/GenericsTests.swift

CHANGELOG.md

…ptions - [x] Reorganize `ConditionalCoderTests`, `DefaultSequenceElementCodingTests`, and `DynamicCodableIdentifierTests` into nested test suites. - [x] Update test descriptions to be more concise and descriptive. - [x] Remove `CHANGELOG` entry about unreachable default case warnings (again 🤦🏻‍♂️). - [x] Simplify multi-line test attribute formatting in `CodableTests`.

qizh added 2 commits November 27, 2025 21:34

Bring indentation back in EnumVariable.swift

a9b3f01

- [x] Corrected indentation for the `caseEncodeExpr` closure to maintain consistent formatting.

qizh marked this pull request as ready for review November 27, 2025 14:42

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Sources/HelperCoders/ValueCoders/Number.swift Outdated Show resolved Hide resolved

qizh marked this pull request as draft November 27, 2025 14:47

qizh added 3 commits November 27, 2025 22:30

Update protocol constraint from SendableMetatype to Sendable

551c9a1

Replaces the `SendableMetatype` constraint with `Sendable` in the `ValueCodingStrategy` extension to align with updated protocol requirements or type definitions.

Fix enum case encoding for cases without arguments

af382df

- [x] Refactors `caseEncodeExpr` to return only the case name for enum cases without associated values, avoiding unnecessary parentheses. This improves code generation for enums with simple cases.

qizh marked this pull request as ready for review November 27, 2025 16:03

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Tests/MetaCodableTests/ConformCodableTests.swift Show resolved Hide resolved

qizh added 6 commits January 21, 2026 18:24

Merge remote-tracking branch 'refs/remotes/upstream/main'

6ca0d90

#Conflicts: # Sources/PluginCore/Variables/Type/EnumVariable.swift # Tests/MetaCodableTests/ConformCodableTests.swift

chore: add *.dia to gitignore

ea720d5

Add Swift dependency analysis files (*.dia) to gitignore as they are temporary build artifacts similar to .d and .o files.

fix: remove duplicate diagnostic expectations in ConformCodableTests

0b3f7dc

Remove duplicate diagnostic test expectations that were incorrectly preserved during merge conflict resolution.

Merge pull request #1 from qizh/fix/warnings-cleanup

6da09a6

- [x] fix: resolve compiler warnings - [x] merge: from `upstream/main`

soumyamahunt requested changes Jan 21, 2026

View reviewed changes

Update CHANGELOG.md

4a3190a

qizh added 15 commits January 30, 2026 15:05

Merge branch 'merge/upstream'

3873f76

docs: fix markdown lint error - add blank line before code block

aa9002e

fix: remove merge conflict markers from CodedAsMixedTypesTests.swift

161b144

Remove leftover merge conflict markers (`<<<<<<< HEAD, =======, >>>>>>>`) from the test file that were accidentally committed during the previous merge.

Merge origin/main into tests/improve/coverage/30-01-26

6cb6b70

Add Swift CI workflow for build and test automation

2344087

Disable main.yml workflow in favor of swift.yml

fae5691

Re-enable main.yml workflow by removing the .disabled extension.

1f3e57c

This workflow will be disabled on GitHub.

chore: simplify Swift workflow name to "Swift build & test"

4e57d33

Update README.md

3ffa20e

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qizh requested a review from soumyamahunt January 30, 2026 10:24