Revert "Fix find_in_batches with customized primary_key"

This reverts commit 761bc751d31c22e2c2fdae2b4cdd435b68b6d783.

This commit wasn't fixing any issue just using the same table for
different models with different primary keys.

1 files changed, 6 insertions, 7 deletions

diff --git a/activerecord/lib/active_record/relation/batches.rb b/activerecord/lib/active_record/relation/batches.rb
index d32048cce1..4d14506965 100644
--- a/activerecord/lib/active_record/relation/batches.rb
+++ b/activerecord/lib/active_record/relation/batches.rb
@@ -36,12 +36,12 @@ module ActiveRecord
     # want multiple workers dealing with the same processing queue. You can
     # make worker 1 handle all the records between id 0 and 10,000 and
     # worker 2 handle from 10,000 and beyond (by setting the +:start+
-    # option on that worker). You can also use non-integer-based primary keys
-    # if start point is set.
+    # option on that worker).
     #
     # It's not possible to set the order. That is automatically set to
-    # ascending on the primary key (e.g. "id ASC") to make the batch ordering
-    # work. You can't set the limit either, that's used to control
+    # ascending on the primary key ("id ASC") to make the batch ordering
+    # work. This also mean that this method only works with integer-based
+    # primary keys. You can't set the limit either, that's used to control
     # the batch sizes.
     #
     #   Person.where("age > 21").find_in_batches do |group|
@@ -62,8 +62,7 @@ module ActiveRecord
         ActiveRecord::Base.logger.warn("Scoped order and limit are ignored, it's forced to be batch order and batch size")
       end
 
-      start = options.delete(:start)
-      start ||= 0
+      start = options.delete(:start).to_i
       batch_size = options.delete(:batch_size) || 1000
 
       relation = relation.reorder(batch_order).limit(batch_size)
@@ -71,7 +70,7 @@ module ActiveRecord
 
       while records.any?
         records_size = records.size
-        primary_key_offset = records.last.send(primary_key)
+        primary_key_offset = records.last.id
 
         yield records