[Breaking] bring resolve into line with require.resolve, which does not respect trailing slashes on non-directories.

Author: ljharb

lib/async.js

@@ -80,7 +80,7 @@ module.exports = function resolve(x, options, callback) {
     var res;
     function validBasedir(basedir) {
         if ((/^(?:\.\.?(?:\/|$)|\/|([A-Za-z]:)?[/\\])/).test(x)) {
-            res = path.resolve(basedir, x);
+            res = path.normalize(path.join(basedir, x));
             if (x === '..' || x.slice(-1) === '/') res += '/';
             if ((/\/$/).test(x) && res === basedir) {
                 loadAsDirectory(res, opts.package, onfile);

lib/sync.js

@@ -61,7 +61,7 @@ module.exports = function (x, options) {
     }
 
     if ((/^(?:\.\.?(?:\/|$)|\/|([A-Za-z]:)?[/\\])/).test(x)) {
-        var res = path.resolve(absoluteStart, x);
+        var res = path.normalize(path.join(basedir, x));
         if (x === '..' || x.slice(-1) === '/') res += '/';
         var m = loadAsFileSync(res) || loadAsDirectorySync(res);
         if (m) return m;

test/resolver.js

@@ -310,6 +310,23 @@ test('async: #121 - treating an existing file as a dir when no basedir', functio
         });
     });
 
+    t.test('with a trailing slash', function (st) {
+        st.plan(4);
+
+        resolve('./' + testFile + '/', function (err, res, pkg) {
+            st.ok(err, 'there is an error');
+            st.notOk(res, 'no result');
+
+            st.equal(err && err.code, 'MODULE_NOT_FOUND', 'error code matches require.resolve');
+            st.equal(
+                err && err.message,
+                'Cannot find module \'./' + testFile + '/\' from \'' + __dirname + '\'',
+                'can not find nonexistent module'
+            );
+            st.end();
+        });
+    });
+
     t.test('with a fake directory', function (st) {
         st.plan(4);
 

test/resolver_sync.js

@@ -235,6 +235,28 @@ test('sync: #121 - treating an existing file as a dir when no basedir', function
         st.end();
     });
 
+    t.test('with a trailing slash', function (st) {
+        var path = './' + testFile + '/';
+        function run() { return resolve.sync(path); }
+
+        var result, error;
+        try {
+            result = run();
+        } catch (e) {
+            error = e;
+        }
+        st.ok(error, 'there is an error');
+        st.notOk(result, 'no result');
+        st.equal(error && error.code, 'MODULE_NOT_FOUND', 'error code matches require.resolve');
+        st.equal(
+            error && error.message,
+            'Cannot find module \'' + path + '\' from \'' + __dirname + '\'',
+            'can not find nonexistent module'
+        );
+
+        st.end();
+    });
+
     t.test('with a fake directory', function (st) {
         function run() { return resolve.sync('./' + testFile + '/blah'); }