From 046638359c5ef6b91d5383fb9d57aa2d89d1bfdf Mon Sep 17 00:00:00 2001
From: Evgeny Poberezkin <e.poberezkin@me.com>
Date: Thu, 24 Nov 2016 21:56:48 +0000
Subject: [PATCH] feat: support async schema/fragment loading, closes #5

---
 keywords/add_keyword.js |  5 ++-
 package.json            |  2 +-
 spec/async.spec.js      | 68 +++++++++++++++++++++++++++++++++++++++++
 spec/patch.spec.js      |  8 ++---
 4 files changed, 77 insertions(+), 6 deletions(-)
 create mode 100644 spec/async.spec.js

diff --git a/keywords/add_keyword.js b/keywords/add_keyword.js
index 2b5f556..b61a3cb 100644
--- a/keywords/add_keyword.js
+++ b/keywords/add_keyword.js
@@ -20,7 +20,10 @@ module.exports = function (ajv, keyword, jsonPatch, patchSchema) {
                   : $ref;
         var validate = ajv.getSchema(id);
         if (validate) return validate.schema;
-        throw new Error('can\'t resolve reference ' + $ref + ' from id ' + it.baseId);
+        var err = new Error('can\'t resolve reference ' + $ref + ' from id ' + it.baseId);
+        err.missingRef = it.resolve.url(it.baseId, $ref);
+        err.missingSchema = it.resolve.normalizeId(it.resolve.fullPath(err.missingRef));
+        throw err;
       }
     },
     metaSchema: {
diff --git a/package.json b/package.json
index 4a66edb..734a2e6 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "ajv-merge-patch",
-  "version": "2.0.2",
+  "version": "2.1.0",
   "description": "$merge and $patch keywords for Ajv JSON-Schema validator to extend schemas",
   "main": "index.js",
   "scripts": {
diff --git a/spec/async.spec.js b/spec/async.spec.js
new file mode 100644
index 0000000..5565be7
--- /dev/null
+++ b/spec/async.spec.js
@@ -0,0 +1,68 @@
+'use strict';
+
+var Ajv = require('ajv');
+var addKeywords = require('..');
+var test = require('./test_validate');
+var assert = require('assert');
+
+describe('async schema loading', function() {
+  var ajv, loadCount;
+
+  beforeEach(function() {
+    ajv = new Ajv({v5: true, loadSchema: loadSchema});
+    addKeywords(ajv);
+    loadCount = 0;
+  });
+
+  describe('$merge', function() {
+    it('should load missing schemas', function (done) {
+      var schema = {
+        "$merge": {
+          "source": { "$ref": "obj.json#" },
+          "with": {
+            "properties": { "q": { "type": "number" } }
+          }
+        }
+      };
+
+      testAsync(schema, '$merge', done);
+    });
+  });
+
+  describe('$patch', function() {
+    it('should load missing schemas', function (done) {
+      var schema = {
+        "$patch": {
+          "source": { "$ref": "obj.json#" },
+          "with": [
+            { "op": "add", "path": "/properties/q", "value": { "type": "number" } }
+          ]
+        }
+      };
+
+      testAsync(schema, '$patch', done);
+    });
+  });
+
+  function testAsync(schema, keyword, done) {
+    ajv.compileAsync(schema, function (err, validate) {
+      if (err) done(err);
+      assert.strictEqual(loadCount, 1);
+      test(validate, keyword);
+      done();
+    });
+  }
+
+  function loadSchema(ref, callback) {
+    if (ref == 'obj.json') {
+      loadCount++;
+      return callback(null, {
+        "id": "obj.json#",
+        "type": "object",
+        "properties": { "p": { "type": "string" } },
+        "additionalProperties": false
+      });
+    }
+    callback(new Error('404: ' + ref));
+  }
+});
diff --git a/spec/patch.spec.js b/spec/patch.spec.js
index 22e145e..42f7b09 100644
--- a/spec/patch.spec.js
+++ b/spec/patch.spec.js
@@ -37,9 +37,9 @@ describe('keyword $patch', function() {
   });
 
   it('should extend schema defined in $ref', function() {
-    ajvInstances.forEach(testMerge);
+    ajvInstances.forEach(testPatch);
 
-    function testMerge(ajv) {
+    function testPatch(ajv) {
       var sourceSchema = {
         "id": "obj.json#",
         "type": "object",
@@ -64,9 +64,9 @@ describe('keyword $patch', function() {
   });
 
   it('should extend schema defined with relative $ref', function() {
-    ajvInstances.forEach(testMerge);
+    ajvInstances.forEach(testPatch);
 
-    function testMerge(ajv) {
+    function testPatch(ajv) {
       var schema = {
         "id": "obj.json#",
         "definitions": {