add safe guard

Signed-off-by: Tobias Gurtzick <[email protected]>

Author: wzrdtales

lib/methods/v2/translatestate.js

@@ -2,6 +2,7 @@ const Promise = require('bluebird');
 const State = require('../../state');
 const Chain = require('../../chain');
 const Migrate = require('./migrate');
+const log = require('db-migrate-shared').log;
 
 const methods = {
   createTable: async (driver, [t], internals) => {
@@ -45,6 +46,17 @@ const methods = {
   },
 
   addIndex: async (driver, [t, i], internals) => {
+    if (!internals.modSchema.i[t][i]) {
+      log.warning(
+        `There was an attempt to create the index "${i}" in the table "${t}".`
+      );
+      log.warning(
+        `This index did not exist at the time of deleting it. ` +
+          `This can happen if an index was created by hand and then deleted` +
+          `by db-migrate. Make sure to recreate it by hand to avoid any problems.`
+      );
+      return Promise.resolve();
+    }
     return driver.addIndex(
       t,
       i,