support index key length for MySQL

app/src/Lib/Util/SchemaManager.php

@@ -183,12 +183,15 @@ protected function processSchema(
     string  $tablePrefix=""
   ) {
     $schema = new Schema();
-
+    $mysqlIndexKeyLen = [];
+
     // Walk through $schemaConfig and build our schema in DBAL format.
 
     foreach($schemaConfig->tables as $tName => $tCfg) {
       $table = $schema->createTable($tablePrefix.$tName);
-
+      // Create the mapper for this table
+      $mysqlIndexKeyLen[$tablePrefix.$tName] = [];
+
       foreach($tCfg->columns as $cName => $cCfg) {
         // We allow "inherited" definitions from the fieldLibrary, so merge together
         // the configurations (if appropriate)
@@ -211,6 +214,21 @@ protected function processSchema(
 
         if($colCfg->type == "string") {
           $options['length'] = $colCfg->size;
+
+          // By default, VARCHAR is limited to a maximum of 255 characters and its limit must be specified implicitly
+          // within a bracket right after its declaration, i.e VARCHAR(200) will limit it to 200 characters long only.
+          // Sometimes, even though you don’t use TEXT or BLOB related type in your table, the Error 1170 may
+          // also appear. It happens in a situation such as when you specify VARCHAR column as primary key,
+          // but wrongly set its length or characters size. VARCHAR can only accept up to 256 characters,
+          // so anything such as VARCHAR(512) will force MySQL to auto-convert the VARCHAR(512) to a SMALLTEXT
+          // datatype, which subsequently fails with error 1170 on key length if the column is used as primary key or
+          // unique or non-unique index
+          if($colCfg->size > 512
+             && in_array($this->driver, array(
+            "Cake\Database\Driver\Mysql"
+          ))) {
+            $mysqlIndexKeyLen[$tablePrefix.$tName][$cName] = "(256)";
+          }
         }
 
         if(isset($colCfg->notnull)) {
@@ -280,8 +298,20 @@ protected function processSchema(
           //     XXX MariadBD is not supported
           $tempColumns = [];
           foreach ($iCfg->columns as $idx => $clm_name) {
+            // Index with key length (only applied to MySQL) and for the use cases where
+            // more than one column is combined to form an index
+            $isExpression = true;
+            if(!empty($mysqlIndexKeyLen[$tablePrefix.$tName][$clm_name])
+               && count($iCfg->columns) > 1
+               && !str_contains($clm_name, "(")) {
+              $iCfg->columns[$idx] = $clm_name = $clm_name . $mysqlIndexKeyLen[$tablePrefix.$tName][$clm_name];
+              $isExpression = false;
+            }
+
+            // Index with expression
             if (! $table->hasColumn($clm_name)) {
-              if(in_array($this->driver, array(
+              if($isExpression
+                 && in_array($this->driver, array(
                   "Cake\Database\Driver\Mysql",
                   "Cake\Database\Driver\Sqlite",
                 ))) {
@@ -298,9 +328,15 @@ protected function processSchema(
           }
 
           if(isset($iCfg->unique) && $iCfg->unique) {
-            $table->addUniqueConstraint($iCfg->columns, $iName, $flags, $options);
+            $table->addUniqueConstraint($iCfg->columns ,
+                                        $iName,
+                                        $flags,
+                                        $options);
           } else {
-            $table->addIndex($iCfg->columns, $iName, $flags, $options);
+            $table->addIndex($iCfg->columns,
+                             $iName,
+                             $flags,
+                             $options);
           }
 
           foreach ($tempColumns as $clm_name) {