Merge pull request #7352 from aripollak/microsecond-timestamp

Fix occasional microsecond conversion inaccuracy
rails · Aug 17, 2012 · 8f4ee48 · 8f4ee48
2 parents cbbf6bf + 53ca22f
commit 8f4ee48
Show file tree

Hide file tree

Showing 4 changed files with 10 additions and 3 deletions.
diff --git a/activerecord/CHANGELOG.md b/activerecord/CHANGELOG.md
@@ -1,5 +1,11 @@
 ## Rails 4.0.0 (unreleased) ##
 
+*   Fix Column.microseconds and Column.fast_string_to_date to avoid converting
+    timestamp seconds to a float, since it occasionally results in inaccuracies
+    with microsecond-precision times. Fixes #7352.
+
+    *Ari Pollak*
+
 *   Raise `ArgumentError` if list of attributes to change is empty in `update_all`.
 
     *Roman Shatsov*

diff --git a/activerecord/lib/active_record/connection_adapters/column.rb b/activerecord/lib/active_record/connection_adapters/column.rb
@@ -208,7 +208,7 @@ def value_to_decimal(value)
           # '0.123456' -> 123456
           # '1.123456' -> 123456
           def microseconds(time)
-            ((time[:sec_fraction].to_f % 1) * 1_000_000).to_i
+            time[:sec_fraction] ? (time[:sec_fraction] * 1_000_000).to_i : 0
           end
 
           def new_date(year, mon, mday)
@@ -233,7 +233,7 @@ def fast_string_to_date(string)
           # Doesn't handle time zones.
           def fast_string_to_time(string)
             if string =~ Format::ISO_DATETIME
-              microsec = ($7.to_f * 1_000_000).to_i
+              microsec = ($7.to_r * 1_000_000).to_i
               new_time $1.to_i, $2.to_i, $3.to_i, $4.to_i, $5.to_i, $6.to_i, microsec
             end
           end

diff --git a/activerecord/test/cases/base_test.rb b/activerecord/test/cases/base_test.rb
@@ -231,6 +231,7 @@ def test_preserving_time_objects
       assert_equal 11, Topic.find(1).written_on.sec
       assert_equal 223300, Topic.find(1).written_on.usec
       assert_equal 9900, Topic.find(2).written_on.usec
+      assert_equal 129346, Topic.find(3).written_on.usec
     end
   end
 

diff --git a/activerecord/test/fixtures/topics.yml b/activerecord/test/fixtures/topics.yml
@@ -25,7 +25,7 @@ third:
   id: 3
   title: The Third Topic of the day
   author_name: Carl
-  written_on: 2005-07-15t15:28:00.0099+01:00
+  written_on: 2012-08-12t20:24:22.129346+00:00
   content: I'm a troll
   approved: true
   replies_count: 1