fix(eslint-plugin): ignore underscore-prefixed params in unresolvedProviderDependencies rule (#281)

Parameters prefixed with `_` are a TypeScript convention for
intentionally unused parameters. The `unresolvedProviderDependencies`
ESLint rule was incorrectly flagging these as unresolved dependencies.

- Add `isDependencyPrefixedWithUnderscore` method to `Provider` DTO to
detect `_`-prefixed params
- Update `GraphHandler` to skip the unresolved dependency check for such
parameters
- Add fixture and test case for a graph with an underscore-prefixed
provider param

Author: guyca

packages/eslint-plugin-obsidian/src/rules/unresolvedProviderDependencies/graphHandler.ts

@@ -17,7 +17,9 @@ export class GraphHandler {
     const graph = this.classAdapter.classToGraph(clazz.node, this.context.currentFilePath)!;
     const providers = graph.resolveProviders();
     for (const provider of graph.getProviders()) {
-      const unresolvedDep = provider.dependencies.find(dep => dep.isNotProvided(providers));
+      const unresolvedDep = provider.dependencies.find(dep => (
+        dep.isNotProvided(providers) && !provider.isDependencyPrefixedWithUnderscore(dep)
+      ));
       if (unresolvedDep) return { provider, unresolvedDep };
     }
   }

packages/eslint-plugin-obsidian/tests/unresolvedProviderDependencies/fixtures/validGraphWithUnderscorePrefixedParam.ts

@@ -0,0 +1,9 @@
+import { graph, ObjectGraph, provides } from 'react-obsidian';
+
+@graph()
+export default class GraphWithUnderscorePrefixedParam extends ObjectGraph {
+  @provides()
+  provider(_unusedParam: string): string {
+    return 'value';
+  }
+}

packages/eslint-plugin-obsidian/tests/unresolvedProviderDependencies/unresolvedDependencies.test.ts

@@ -71,6 +71,11 @@ ruleTester.run(
         filename: 'validGraphWithExternalSubgraph.ts',
         skip: skipValid,
       },
+      {
+        code: loadFixture('validGraphWithUnderscorePrefixedParam.ts'),
+        filename: 'validGraphWithUnderscorePrefixedParam.ts',
+        skip: skipValid,
+      },
     ],
     invalid: [
       {

packages/ts-morph-extensions/src/dto/provider.ts

@@ -46,6 +46,10 @@ export class Provider {
     };
   }
 
+  public isDependencyPrefixedWithUnderscore(dependency: Parameter) {
+    return this.dependencies.some(dep => dep.node.getName() === `_${dependency.name}`);
+  }
+
   public get dependencies() {
     return this.node.getParameters().map(param => new Parameter(param));
   }