chore: switch nyc to c8

Makefile.js

@@ -589,12 +589,12 @@ target.mocha = () => {
 
     echo("Running unit tests");
 
-    lastReturn = exec(`${getBinFile("nyc")} -- ${MOCHA} --forbid-only -R progress -t ${MOCHA_TIMEOUT} -c ${TEST_FILES}`);
+    lastReturn = exec(`${getBinFile("c8")} -- ${MOCHA} --forbid-only -R progress -t ${MOCHA_TIMEOUT} -c ${TEST_FILES}`);
     if (lastReturn.code !== 0) {
         errors++;
     }
 
-    lastReturn = exec(`${getBinFile("nyc")} check-coverage --statement 98 --branch 97 --function 98 --lines 98`);
+    lastReturn = exec(`${getBinFile("c8")} check-coverage --statement 98 --branch 97 --function 98 --lines 98`);
     if (lastReturn.code !== 0) {
         errors++;
     }

lib/cli-engine/file-enumerator.js

@@ -122,7 +122,8 @@ function statSafeSync(filePath) {
     try {
         return fs.statSync(filePath);
     } catch (error) {
-        /* istanbul ignore next */
+
+        /* c8 ignore next */
         if (error.code !== "ENOENT") {
             throw error;
         }
@@ -141,7 +142,8 @@ function readdirSafeSync(directoryPath) {
     try {
         return fs.readdirSync(directoryPath, { withFileTypes: true });
     } catch (error) {
-        /* istanbul ignore next */
+
+        /* c8 ignore next */
         if (error.code !== "ENOENT") {
             throw error;
         }

lib/linter/code-path-analysis/code-path-segment.js

@@ -88,10 +88,10 @@ class CodePathSegment {
             }
         });
 
-        /* istanbul ignore if */
+        /* c8 ignore start */
         if (debug.enabled) {
             this.internal.nodes = [];
-        }
+        }/* c8 ignore stop */
     }
 
     /**

lib/linter/code-path-analysis/code-path-state.js

@@ -59,7 +59,7 @@ function getContinueContext(state, label) {
         context = context.upper;
     }
 
-    /* istanbul ignore next: foolproof (syntax error) */
+    /* c8 ignore next */
     return null;
 }
 
@@ -79,7 +79,7 @@ function getBreakContext(state, label) {
         context = context.upper;
     }
 
-    /* istanbul ignore next: foolproof (syntax error) */
+    /* c8 ignore next */
     return null;
 }
 
@@ -433,7 +433,7 @@ class CodePathState {
                  */
                 return context;
 
-            /* istanbul ignore next */
+            /* c8 ignore next */
             default:
                 throw new Error("unreachable");
         }
@@ -1030,7 +1030,7 @@ class CodePathState {
                 };
                 break;
 
-            /* istanbul ignore next */
+            /* c8 ignore next */
             default:
                 throw new Error(`unknown type: "${type}"`);
         }
@@ -1095,7 +1095,7 @@ class CodePathState {
                 );
                 break;
 
-            /* istanbul ignore next */
+            /* c8 ignore next */
             default:
                 throw new Error("unreachable");
         }
@@ -1392,11 +1392,12 @@ class CodePathState {
 
         const context = getBreakContext(this, label);
 
-        /* istanbul ignore else: foolproof (syntax error) */
+
         if (context) {
             context.brokenForkContext.add(forkContext.head);
         }
 
+        /* c8 ignore next */
         forkContext.replaceHead(forkContext.makeUnreachable(-1, -1));
     }
 
@@ -1417,7 +1418,6 @@ class CodePathState {
 
         const context = getContinueContext(this, label);
 
-        /* istanbul ignore else: foolproof (syntax error) */
         if (context) {
             if (context.continueDestSegments) {
                 makeLooped(this, forkContext.head, context.continueDestSegments);

lib/linter/code-path-analysis/debug-helpers.js

@@ -20,7 +20,7 @@ const debug = require("debug")("eslint:code-path");
  * @param {CodePathSegment} segment A segment to get.
  * @returns {string} Id of the segment.
  */
-/* istanbul ignore next */
+/* c8 ignore next */
 function getId(segment) { // eslint-disable-line jsdoc/require-jsdoc -- Ignoring
     return segment.id + (segment.reachable ? "" : "!");
 }
@@ -67,7 +67,7 @@ module.exports = {
      * @param {boolean} leaving A flag whether or not it's leaving
      * @returns {void}
      */
-    dumpState: !debug.enabled ? debug : /* istanbul ignore next */ function(node, state, leaving) {
+    dumpState: !debug.enabled ? debug : /* c8 ignore next */ function(node, state, leaving) {
         for (let i = 0; i < state.currentSegments.length; ++i) {
             const segInternal = state.currentSegments[i].internal;
 
@@ -98,7 +98,7 @@ module.exports = {
      * @see http://www.graphviz.org
      * @see http://www.webgraphviz.com
      */
-    dumpDot: !debug.enabled ? debug : /* istanbul ignore next */ function(codePath) {
+    dumpDot: !debug.enabled ? debug : /* c8 ignore next */ function(codePath) {
         let text =
             "\n" +
             "digraph {\n" +

lib/linter/code-path-analysis/id-generator.js

@@ -33,10 +33,10 @@ class IdGenerator {
     next() {
         this.n = 1 + this.n | 0;
 
-        /* istanbul ignore if */
+        /* c8 ignore start */
         if (this.n < 0) {
             this.n = 1;
-        }
+        }/* c8 ignore stop */
 
         return this.prefix + this.n;
     }

lib/linter/timing.js

@@ -9,7 +9,7 @@
 // Helpers
 //------------------------------------------------------------------------------
 
-/* istanbul ignore next */
+/* c8 ignore next */
 /**
  * Align the string to left
  * @param {string} str string to evaluate
@@ -22,7 +22,7 @@ function alignLeft(str, len, ch) {
     return str + new Array(len - str.length + 1).join(ch || " ");
 }
 
-/* istanbul ignore next */
+/* c8 ignore next */
 /**
  * Align the string to right
  * @param {string} str string to evaluate
@@ -64,7 +64,7 @@ function getListSize() {
     return TIMING_ENV_VAR_AS_INTEGER > 10 ? TIMING_ENV_VAR_AS_INTEGER : MINIMUM_SIZE;
 }
 
-/* istanbul ignore next */
+/* c8 ignore next */
 /**
  * display the data
  * @param {Object} data Data object to be displayed
@@ -119,7 +119,7 @@ function display(data) {
     console.log(table.join("\n")); // eslint-disable-line no-console -- Debugging function
 }
 
-/* istanbul ignore next */
+/* c8 ignore next */
 module.exports = (function() {
 
     const data = Object.create(null);

lib/rules/array-callback-return.js

@@ -125,7 +125,7 @@ function getArrayMethodName(node) {
         }
     }
 
-    /* istanbul ignore next: unreachable */
+    /* c8 ignore next */
     return null;
 }
 

lib/rules/global-require.js

@@ -28,10 +28,11 @@ function findReference(scope, node) {
     const references = scope.references.filter(reference => reference.identifier.range[0] === node.range[0] &&
             reference.identifier.range[1] === node.range[1]);
 
-    /* istanbul ignore else: correctly returns null */
     if (references.length === 1) {
         return references[0];
     }
+
+    /* c8 ignore next */
     return null;
 
 }

lib/rules/indent-legacy.js

@@ -18,8 +18,8 @@ const astUtils = require("./utils/ast-utils");
 //------------------------------------------------------------------------------
 // Rule Definition
 //------------------------------------------------------------------------------
-
-/* istanbul ignore next: this rule has known coverage issues, but it's deprecated and shouldn't be updated in the future anyway. */
+// this rule has known coverage issues, but it's deprecated and shouldn't be updated in the future anyway.
+/* c8 ignore next */
 /** @type {import('../shared/types').Rule} */
 module.exports = {
     meta: {
@@ -212,10 +212,10 @@ module.exports = {
             if (context.options[0] === "tab") {
                 indentSize = 1;
                 indentType = "tab";
-            } else /* istanbul ignore else : this will be caught by options validation */ if (typeof context.options[0] === "number") {
+            } else /* c8 ignore start */ if (typeof context.options[0] === "number") {
                 indentSize = context.options[0];
                 indentType = "space";
-            }
+            }/* c8 ignore stop */
 
             if (context.options[1]) {
                 const opts = context.options[1];

lib/rules/new-cap.js

@@ -39,10 +39,10 @@ const CAPS_ALLOWED = [
  */
 function checkArray(obj, key, fallback) {
 
-    /* istanbul ignore if */
+    /* c8 ignore start */
     if (Object.prototype.hasOwnProperty.call(obj, key) && !Array.isArray(obj[key])) {
         throw new TypeError(`${key}, if provided, must be an Array`);
-    }
+    }/* c8 ignore stop */
     return obj[key] || fallback;
 }
 

lib/rules/no-extra-boolean-cast.js

@@ -188,7 +188,7 @@ module.exports = {
                     }
                     return precedence(node) <= precedence(parent);
 
-                /* istanbul ignore next */
+                /* c8 ignore next */
                 default:
                     throw new Error(`Unexpected parent type: ${parent.type}`);
             }

lib/rules/no-extra-parens.js

@@ -634,10 +634,10 @@ module.exports = {
 
                 currentNode = currentNode.parent;
 
-                /* istanbul ignore if */
+                /* c8 ignore start */
                 if (currentNode === null) {
                     throw new Error("Nodes are not in the ancestor-descendant relationship.");
-                }
+                }/* c8 ignore stop */
 
                 path.push(currentNode);
             }

lib/rules/no-labels.js

@@ -98,7 +98,7 @@ module.exports = {
                 info = info.upper;
             }
 
-            /* istanbul ignore next: syntax error */
+            /* c8 ignore next */
             return "other";
         }
 

lib/rules/no-useless-computed-key.js

@@ -74,7 +74,7 @@ function hasUselessComputedKey(node) {
 
             return value !== "constructor";
 
-        /* istanbul ignore next */
+        /* c8 ignore next */
         default:
             throw new Error(`Unexpected node type: ${node.type}`);
     }

lib/rules/no-var.js

@@ -90,7 +90,7 @@ function getScopeNode(node) {
         }
     }
 
-    /* istanbul ignore next : unreachable */
+    /* c8 ignore next */
     return null;
 }
 

lib/rules/padded-blocks.js

@@ -186,7 +186,7 @@ module.exports = {
                 case "ClassBody":
                     return options.classes;
 
-                /* istanbul ignore next */
+                /* c8 ignore next */
                 default:
                     throw new Error("unreachable");
             }

lib/rules/prefer-arrow-callback.js

@@ -53,7 +53,7 @@ function getVariableOfArguments(scope) {
         }
     }
 
-    /* istanbul ignore next */
+    /* c8 ignore next */
     return null;
 }
 
@@ -126,7 +126,7 @@ function getCallbackInfo(node) {
         parent = parent.parent;
     }
 
-    /* istanbul ignore next */
+    /* c8 ignore next */
     throw new Error("unreachable");
 }
 

lib/rules/prefer-rest-params.js

@@ -30,7 +30,7 @@ function getVariableOfArguments(scope) {
         }
     }
 
-    /* istanbul ignore next : unreachable */
+    /* c8 ignore next */
     return null;
 }
 

lib/rules/require-yield.js

@@ -68,7 +68,6 @@ module.exports = {
             // Increases the count of `yield` keyword.
             YieldExpression() {
 
-                /* istanbul ignore else */
                 if (stack.length > 0) {
                     stack[stack.length - 1] += 1;
                 }

lib/rules/utils/ast-utils.js

@@ -1350,7 +1350,7 @@ module.exports = {
             }
         }
 
-        /* istanbul ignore next */
+        /* c8 ignore next */
         return true;
     },
 

lib/shared/logging.js

@@ -7,7 +7,7 @@
 
 /* eslint no-console: "off" -- Logging util */
 
-/* istanbul ignore next */
+/* c8 ignore next */
 module.exports = {
 
     /**

lib/source-code/token-store/cursor.js

@@ -69,7 +69,7 @@ module.exports = class Cursor {
      * @returns {boolean} `true` if the next token exists.
      * @abstract
      */
-    /* istanbul ignore next */
+    /* c8 ignore next */
     moveNext() { // eslint-disable-line class-methods-use-this -- Unused
         throw new Error("Not implemented.");
     }

package.json

@@ -99,6 +99,7 @@
     "@babel/core": "^7.4.3",
     "@babel/preset-env": "^7.4.3",
     "babel-loader": "^8.0.5",
+    "c8": "^7.12.0",
     "chai": "^4.0.1",
     "cheerio": "^0.22.0",
     "common-tags": "^1.8.0",
@@ -142,7 +143,6 @@
     "mocha-junit-reporter": "^2.0.0",
     "node-polyfill-webpack-plugin": "^1.0.3",
     "npm-license": "^0.3.3",
-    "nyc": "^15.0.1",
     "pirates": "^4.0.5",
     "progress": "^2.0.3",
     "proxyquire": "^2.0.1",