fix(espower): throw Error if AST is already instrumented

power-assert-js · Feb 24, 2015 · 1d47bdc · 1d47bdc
1 parent 8a0028e
commit 1d47bdc
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diff --git a/lib/assertion-visitor.js b/lib/assertion-visitor.js
@@ -4,6 +4,7 @@ var estraverse = require('estraverse'),
     escodegen = require('escodegen'),
     espurify = require('espurify'),
     clone = require('clone'),
+    deepEqual = require('deep-equal'),
     syntax = estraverse.Syntax,
     canonicalCodeOptions = {
         format: {
@@ -57,13 +58,31 @@ AssertionVisitor.prototype.enter = function (currentNode, parentNode) {
     }
 };
 
+AssertionVisitor.prototype.ensureNotInstrumented = function (currentNode) {
+    if (currentNode.type === syntax.CallExpression) {
+        if (currentNode.callee.type === syntax.MemberExpression) {
+            var prop = currentNode.callee.property;
+            if (prop.type === syntax.Identifier && prop.name === '_expr') {
+                if (deepEqual(espurify(currentNode.callee.object), espurify(this.powerAssertCallee))) {
+                    var errorMessage = 'Attempted to transform AST twice.';
+                    if (this.options.path) {
+                        errorMessage += ' path: ' + this.options.path;
+                    }
+                    throw new Error(errorMessage);
+                }
+            }
+        }
+    }
+};
+
 AssertionVisitor.prototype.enterArgument = function (currentNode, parentNode, path) {
     var argMatchResult = this.matcher.matchArgument(currentNode, parentNode);
     if (argMatchResult) {
         if (argMatchResult.name === 'message' && argMatchResult.kind === 'optional') {
             // skip optional message argument
             return undefined;
         }
+        this.ensureNotInstrumented(currentNode);
         // entering target argument
         this.currentArgumentPath = [].concat(path);
         return undefined;

diff --git a/package.json b/package.json
@@ -12,6 +12,7 @@
   },
   "dependencies": {
     "clone": "~0.2.0",
+    "deep-equal": "~1.0.0",
     "escallmatch": "~1.0.1",
     "escodegen": "~1.4.1",
     "espurify": "~1.0.0",