internal: use swc with ts-node

[yaacovCR]

this currently requires a few changes to c8 control statements to ensure complete code coverage presumably secondary to a bug/difference between how tsc and swc handle source mapping

also: use --import with register script instead of --loader to silence node.js warning regarding --loader

[Copilot]

Pull Request Overview

This PR switches the project to use SWC with ts-node by adjusting coverage ignore directives for source-mapping differences and replacing --loader ts-node/esm with a --import registration script.

• Update c8 ignore annotations (+comments and ignore counts) across multiple GraphQL source files to account for SWC source mapping.
• Introduce resources/register-ts-node.js and update all npm & Mocha scripts to use node --import instead of --loader.
• Add @swc/core to devDependencies to enable SWC compilation.

Reviewed Changes

Copilot reviewed 11 out of 13 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
src/validation/rules/PossibleTypeExtensionsRule.ts	Adjusted c8 ignore comments/lines around unreachable invariant.
src/utilities/valueFromAST.ts	Updated c8 ignore annotations for SWC mapping in valueFromAST.
src/utilities/printSchema.ts	Updated c8 ignore annotations in printType for input object.
src/utilities/mapSchemaConfig.ts	Updated c8 ignore annotations in mapSchemaConfig on input types.
src/utilities/findSchemaChanges.ts	Updated c8 ignore annotations in typeKindName.
src/utilities/astFromValue.ts	Updated c8 ignore annotations in astFromValue.
src/type/introspection.ts	Updated c8 ignore annotations in introspection __Type resolver.
src/execution/execute.ts	Updated c8 ignore annotations in completeValue.
resources/register-ts-node.js	Added ESM registration script for ts-node import-based loader.
package.json	Switched npm script flags from --loader to --import and added @swc/core.
.mocharc.yml	Replaced Mocha loader=ts-node/esm option with import=./resources/register-ts-node.js.

Comments suppressed due to low confidence (3)

.mocharc.yml:7

• The indentation under node-option may be incorrect, which can cause Mocha to ignore this setting. Verify YAML spacing so that each option is a direct child of node-option.

  - 'import=./resources/register-ts-node.js'

src/validation/rules/PossibleTypeExtensionsRule.ts:119

• [nitpick] This coverage-ignore comment and directive is duplicated across many files. Consider centralizing SWC-related coverage ignore in the project’s c8 configuration or as a shared helper, reducing repetitive boilerplate and future maintenance.

    // c8 control statement technically placed a line early secondary to

src/utilities/printSchema.ts:146

• [nitpick] Ignoring the next four lines may hide coverage gaps beyond the invariant check. If possible, target only the unreachable invariant call or use /* c8 ignore next */ without a count to limit the ignored scope.

    /* c8 ignore next 4 */

[yaacovCR]

swc = observably faster on my machine, seems like a win.

I tries tsx which uses esbuild under the hood, but there is a complication with tsx use of keepNames options for esbuild that messes up code coverage:

evanw/esbuild#4239
privatenumber/tsx#659

[benjie]

Long term we should move to native node type stripping.

[yaacovCR]

Long term we should move to native node type stripping.

#4460

once we drop v20