Improve Sindri Manifest lint output by discriminating circuit type

When there are Sindri Manifest schema issues, the linting output was previously
not as helpful as it could be because issues would be logged across all circuit
types. This happened because the validator wasn't able to accurately
discriminate the union of different subschemas. This PR manually discriminates
the circuit type and modifies the schema that we're validating against to be
specifically for the matching subschema. The code is a little verbose/hacky,
but the error messages are significantly more helpful so I think the tradeoff
is well worth it.

Merges #74

src/cli/lint.ts

@@ -1,3 +1,4 @@
+import assert from "assert";
 import { existsSync, readFileSync } from "fs";
 import path from "path";
 import process from "process";
@@ -76,6 +77,71 @@ export const lintCommand = new Command()
       return process.exit(1);
     }
 
+    // Determine the circuit type and manually discriminate the subschema type to narrow down the
+    // schema so that the user gets more relevant validation errors.
+    assert(Array.isArray(sindriManifestJsonSchema.anyOf));
+    let subSchema: Schema | undefined;
+    if (!("circuitType" in sindriJson) || !sindriJson.circuitType) {
+      subSchema = undefined;
+    } else if (sindriJson.circuitType === "circom") {
+      subSchema = sindriManifestJsonSchema.anyOf.find((option: Schema) =>
+        /circom/i.test(option["$ref"] ?? ""),
+      );
+    } else if (sindriJson.circuitType === "gnark") {
+      subSchema = sindriManifestJsonSchema.anyOf.find((option: Schema) =>
+        /gnark/i.test(option["$ref"] ?? ""),
+      );
+    } else if (sindriJson.circuitType === "halo2") {
+      if (
+        "halo2Version" in sindriJson &&
+        sindriJson.halo2Version === "axiom-v0.2.2"
+      ) {
+        subSchema = sindriManifestJsonSchema.anyOf.find((option: Schema) =>
+          /halo2axiomv022/i.test(option["$ref"] ?? ""),
+        );
+      } else if (
+        "halo2Version" in sindriJson &&
+        sindriJson.halo2Version === "axiom-v0.3.0"
+      ) {
+        subSchema = sindriManifestJsonSchema.anyOf.find((option: Schema) =>
+          /halo2axiomv022/i.test(option["$ref"] ?? ""),
+        );
+      } else {
+        // We can't discriminate the different halo2 manifests if there's not a valid `halo2Version`
+        // so we'll just filter down the `anyOf` to the halo2 manifests instead of picking one.
+        subSchema = {
+          anyOf: sindriManifestJsonSchema.anyOf.filter((option: Schema) =>
+            /halo2/i.test(option["$ref"] ?? ""),
+          ),
+        };
+      }
+    } else if (sindriJson.circuitType === "noir") {
+      subSchema = sindriManifestJsonSchema.anyOf.find((option: Schema) =>
+        /noir/i.test(option["$ref"] ?? ""),
+      );
+    }
+    if (subSchema) {
+      delete sindriManifestJsonSchema.anyOf;
+      sindriManifestJsonSchema = { ...sindriManifestJsonSchema, ...subSchema };
+    } else {
+      sindri.logger.warn(
+        `Circuit type is not configured in "${sindriJsonPath}" so some linting steps will be ` +
+          "skipped and the manifest linting output will be very noisy. Please correct " +
+          '"circuiType" in "sindri.json" and rerun "sindri lint" to get better linting.',
+      );
+    }
+    const circuitType: "circom" | "gnark" | "halo2" | "noir" | null =
+      "circuitType" in sindriJson &&
+      typeof sindriJson.circuitType === "string" &&
+      ["circom", "gnark", "halo2", "noir"].includes(sindriJson.circuitType)
+        ? (sindriJson.circuitType as "circom" | "gnark" | "halo2" | "noir")
+        : null;
+    if (circuitType) {
+      sindri.logger.debug(`Detected circuit type "${circuitType}".`);
+    } else {
+      sindri.logger.debug("No circuit type detected!");
+    }
+
     // Validate `sindri.json`.
     const manifestValidator = new JsonValidator();
     const validationStatus = manifestValidator.validate(