Stop sharing params object across rules because doing so is unstable for asynchronous rules (fixes #510).

demo/markdownlint-browser.js

@@ -1498,22 +1498,22 @@ function lintContent(ruleList, name, content, md, config, frontMatter, handleRul
     var aliasToRuleNames = mapAliasToRuleNames(ruleList);
     var _a = getEnabledRulesPerLineNumber(ruleList, lines, frontMatterLines, noInlineConfig, config, aliasToRuleNames), effectiveConfig = _a.effectiveConfig, enabledRulesPerLineNumber = _a.enabledRulesPerLineNumber;
     // Create parameters for rules
-    var params = {
+    var paramsBase = helpers.deepFreeze({
-        "name": helpers.deepFreeze(name),
+        name: name,
-        "tokens": helpers.deepFreeze(tokens),
+        tokens: tokens,
-        "lines": helpers.deepFreeze(lines),
+        lines: lines,
-        "frontMatterLines": helpers.deepFreeze(frontMatterLines)
+        frontMatterLines: frontMatterLines
-    };
+    });
-    cache.lineMetadata(helpers.getLineMetadata(params));
+    cache.lineMetadata(helpers.getLineMetadata(paramsBase));
-    cache.flattenedLists(helpers.flattenLists(params.tokens));
+    cache.flattenedLists(helpers.flattenLists(paramsBase.tokens));
-    cache.codeBlockAndSpanRanges(helpers.codeBlockAndSpanRanges(params, cache.lineMetadata()));
+    cache.codeBlockAndSpanRanges(helpers.codeBlockAndSpanRanges(paramsBase, cache.lineMetadata()));
     // Function to run for each rule
     var results = [];
     // eslint-disable-next-line jsdoc/require-jsdoc
     function forRule(rule) {
         // Configure rule
         var ruleName = rule.names[0].toUpperCase();
-        params.config = effectiveConfig[ruleName];
+        var params = __assign(__assign({}, paramsBase), { "config": effectiveConfig[ruleName] });
         // eslint-disable-next-line jsdoc/require-jsdoc
         function throwError(property) {
             throw new Error("Property '" + property + "' of onError parameter is incorrect.");

lib/markdownlint.js

@@ -489,16 +489,16 @@ function lintContent(
       aliasToRuleNames
     );
   // Create parameters for rules
-  const params = {
+  const paramsBase = helpers.deepFreeze({
-    "name": helpers.deepFreeze(name),
+    name,
-    "tokens": helpers.deepFreeze(tokens),
+    tokens,
-    "lines": helpers.deepFreeze(lines),
+    lines,
-    "frontMatterLines": helpers.deepFreeze(frontMatterLines)
+    frontMatterLines
-  };
+  });
-  cache.lineMetadata(helpers.getLineMetadata(params));
+  cache.lineMetadata(helpers.getLineMetadata(paramsBase));
-  cache.flattenedLists(helpers.flattenLists(params.tokens));
+  cache.flattenedLists(helpers.flattenLists(paramsBase.tokens));
   cache.codeBlockAndSpanRanges(
-    helpers.codeBlockAndSpanRanges(params, cache.lineMetadata())
+    helpers.codeBlockAndSpanRanges(paramsBase, cache.lineMetadata())
   );
   // Function to run for each rule
   let results = [];
@@ -506,7 +506,10 @@ function lintContent(
   function forRule(rule) {
     // Configure rule
     const ruleName = rule.names[0].toUpperCase();
-    params.config = effectiveConfig[ruleName];
+    const params = {
+      ...paramsBase,
+      "config": effectiveConfig[ruleName]
+    };
     // eslint-disable-next-line jsdoc/require-jsdoc
     function throwError(property) {
       throw new Error(

test/markdownlint-test-custom-rules.js

@@ -1195,6 +1195,70 @@ test("customRulesAsyncThrowsInSyncContext", (t) => {
   );
 });
 
+test("customRulesParamsAreStable", (t) => {
+  t.plan(4);
+  const config1 = { "value1": 10 };
+  const config2 = { "value2": 20 };
+  const options = {
+    "config": {
+      "MD010": true,
+      "name1": config1,
+      "MD013": { "line_length": 200 },
+      "name2": config2,
+      "MD033": false
+    },
+    "customRules": [
+      {
+        "names": [ "name1" ],
+        "description": "description1",
+        "tags": [ "tag" ],
+        "asynchronous": true,
+        "function":
+          (params) => {
+            t.deepEqual(
+              params.config,
+              config1,
+              `Unexpected config in sync path: ${params.config}.`
+            );
+            return Promise.resolve().then(() => {
+              t.deepEqual(
+                params.config,
+                config1,
+                `Unexpected config in async path: ${params.config}.`
+              );
+            });
+          }
+      },
+      {
+        "names": [ "name2" ],
+        "description": "description2",
+        "tags": [ "tag" ],
+        "asynchronous": true,
+        "function":
+          (params) => {
+            const { config } = params;
+            t.deepEqual(
+              config,
+              config2,
+              `Unexpected config in sync path: ${config}.`
+            );
+            return Promise.resolve().then(() => {
+              t.deepEqual(
+                config,
+                config2,
+                `Unexpected config in async path: ${config}.`
+              );
+            });
+          }
+      }
+    ],
+    "strings": {
+      "string": "# Heading"
+    }
+  };
+  return markdownlint.promises.markdownlint(options).then(() => null);
+});
+
 test("customRulesAsyncReadFiles", (t) => {
   t.plan(3);
   const options = {