fix: Set app.migrating to true when called via migrateByName

lib/models/migration.js

@@ -62,6 +62,17 @@ module.exports = function(Migration, options) {
     assert(typeof name === 'string', 'The to argument must be a string, not ' + typeof name);
     assert(typeof cb === 'function', 'The cb argument must be a function, not ' + typeof cb);
 
+    if (Migration.app.migrating) {
+      Migration.log.warn('Unable to start migration: already running');
+      process.nextTick(function() {
+        cb();
+      });
+      return cb.promise;
+    }
+
+    Migration.hrstart = process.hrtime();
+    Migration.app.migrating = true;
+
     Migration.log.info(name, 'running.');
     const scriptPath = path.resolve(path.join(Migration.migrationsDir, name));
 

test/fixtures/simple-app/server/migrations/0001-initialize.js

@@ -1,8 +1,8 @@
 module.exports = {
   up: function(dataSource, next) {
-    next();
+    process.nextTick(() => next())
   },
   down: function(dataSource, next) {
-    next();
+    process.nextTick(() => next())
   }
 };

test/fixtures/simple-app/server/migrations/0002-somechanges.js

@@ -1,8 +1,8 @@
 module.exports = {
   up: function(dataSource, next) {
-    next();
+    process.nextTick(() => next())
   },
   down: function(dataSource, next) {
-    next();
+    process.nextTick(() => next())
   }
 };

test/fixtures/simple-app/server/migrations/0003-morechanges.js

@@ -1,8 +1,8 @@
 module.exports = {
   up: function(dataSource, next) {
-    next();
+    process.nextTick(() => next())
   },
   down: function(dataSource, next) {
-    next();
+    process.nextTick(() => next())
   }
 };

test/test.js

@@ -85,6 +85,20 @@ describe('loopback db migrate', function() {
       .catch(done);
     });
 
+    describe('migrateByName', function() {
+      it('should set a property on app to indicate that migration is running', function(done) {
+        var self = this;
+        expect(app.migrating).to.be.undefined;
+        var promise = app.models.Migration.migrateByName('0002-somechanges.js');
+        expect(app.migrating).to.be.true;
+        promise.then(function() {
+          expect(app.migrating).to.be.undefined;
+          done();
+        })
+        .catch(done);
+      });
+    });
+
     describe('migrate', function() {
       it('should set a property on app to indicate that migrations are running', function(done) {
         var self = this;