From 1ea86e6ad16c218714b39209bac3be99a0c598dd Mon Sep 17 00:00:00 2001
From: Nicolas Morel <nicolas@morel.io>
Date: Sun, 24 Jul 2016 15:08:51 +0200
Subject: [PATCH] Make coercion happen earlier in the validation

Fixes #960.
---
 lib/any.js    | 11 ++++++++
 lib/index.js  | 39 +++++++++++++++-----------
 test/index.js | 76 +++++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 110 insertions(+), 16 deletions(-)

diff --git a/lib/any.js b/lib/any.js
index 192742cbb..917faccc0 100755
--- a/lib/any.js
+++ b/lib/any.js
@@ -475,6 +475,17 @@ module.exports = internals.Any = class {
             };
         };
 
+        if (this._coerce) {
+            const coerced = this._coerce.call(this, value, state, options);
+            if (coerced.errors) {
+                value = coerced.value;
+                errors = errors.concat(coerced.errors);
+                return finish();                            // Coerced error always aborts early
+            }
+
+            value = coerced.value;
+        }
+
         // Check presence requirements
 
         const presence = this._flags.presence || options.presence;
diff --git a/lib/index.js b/lib/index.js
index 3ed003de0..0ed19155e 100755
--- a/lib/index.js
+++ b/lib/index.js
@@ -213,19 +213,30 @@ internals.root = function () {
 
             };
 
-            if (extension.coerce || extension.pre) {
-                type.prototype._base = function (value, state, options) {
+            if (extension.coerce) {
+                type.prototype._coerce = function (value, state, options) {
+
+                    if (ctor.prototype._coerce) {
+                        const baseRet = ctor.prototype._coerce.call(this, value, state, options);
 
-                    let ret;
-                    if (extension.coerce) {
-                        ret = extension.coerce.call(this, value, state, options);
-                        if (ret instanceof Errors.Err) {
-                            return { value, errors: ret };
+                        if (baseRet.errors) {
+                            return baseRet;
                         }
 
-                        value = ret;
+                        value = baseRet.value;
+                    }
+
+                    const ret = extension.coerce.call(this, value, state, options);
+                    if (ret instanceof Errors.Err) {
+                        return { value, errors: ret };
                     }
 
+                    return { value: ret };
+                };
+            }
+            if (extension.pre) {
+                type.prototype._base = function (value, state, options) {
+
                     if (ctor.prototype._base) {
                         const baseRet = ctor.prototype._base.call(this, value, state, options);
 
@@ -236,16 +247,12 @@ internals.root = function () {
                         value = baseRet.value;
                     }
 
-                    if (extension.pre) {
-                        ret = extension.pre.call(this, value, state, options);
-                        if (ret instanceof Errors.Err) {
-                            return { value, errors: ret };
-                        }
-
-                        return { value: ret };
+                    const ret = extension.pre.call(this, value, state, options);
+                    if (ret instanceof Errors.Err) {
+                        return { value, errors: ret };
                     }
 
-                    return { value };
+                    return { value: ret };
                 };
             }
 
diff --git a/test/index.js b/test/index.js
index 71cd66421..cc63fe26b 100755
--- a/test/index.js
+++ b/test/index.js
@@ -2329,6 +2329,82 @@ describe('Joi', () => {
             done();
         });
 
+        it('defines a custom type coercing its input value that runs early enough', (done) => {
+
+            const customJoi = Joi.extend({
+                base: Joi.string(),
+                coerce(value, state, options) {
+
+                    return 'foobar';
+                },
+                name: 'myType'
+            });
+
+            const schema = customJoi.myType();
+            const result = schema.validate('');
+            expect(result.error).to.be.null();
+            expect(result.value).to.equal('foobar');
+
+            done();
+        });
+
+        it('defines multiple levels of coercion', (done) => {
+
+            const customJoi = Joi.extend({
+                base: Joi.string(),
+                coerce(value, state, options) {
+
+                    return 'foobar';
+                },
+                name: 'myType'
+            });
+
+            const customJoi2 = customJoi.extend({
+                base: customJoi.myType(),
+                coerce(value, state, options) {
+
+                    expect(value).to.equal('foobar');
+                    return 'baz';
+                },
+                name: 'myType'
+            });
+
+            const schema = customJoi2.myType();
+            const result = schema.validate('');
+            expect(result.error).to.be.null();
+            expect(result.value).to.equal('baz');
+
+            done();
+        });
+
+        it('defines multiple levels of coercion where base fails', (done) => {
+
+            const customJoi = Joi.extend({
+                base: Joi.string(),
+                coerce(value, state, options) {
+
+                    return this.createError('any.invalid', null, state, options);
+                },
+                name: 'myType'
+            });
+
+            const customJoi2 = customJoi.extend({
+                base: customJoi.myType(),
+                coerce(value, state, options) {
+
+                    expect(value).to.equal('foobar');
+                    return 'baz';
+                },
+                name: 'myType'
+            });
+
+            const schema = customJoi2.myType();
+            const result = schema.validate('');
+            expect(result.error).to.an.error('"value" contains an invalid value');
+
+            done();
+        });
+
         it('defines a custom type casting its input value', (done) => {
 
             const customJoi = Joi.extend({