Migration timestamp clash problems with generators
Reported by Russell Quinn | June 25th, 2008 @ 06:26 PM
Hello,
Creating multiple migrations automatically from a generate script causes problems with the new timestamp based migration filenames as they occur at the same second.
e.g.
m.migration_template "db/migrate/add_session_table.rb", "db/migrate", :migration_file_name => 'add_session_table'
m.migration_template "db/migrate/create_casein_users.rb", "db/migrate", :migration_file_name => 'create_casein_users'
creates:
20080625170543_add_session_table.rb
20080625170543_create_casein_users.rb
Obviously there's problems with autodetecting this and just incrementing the last digit, but maybe it's worth suffixing these clashes with a further qualifying digit? i.e. There's another level of granularity to mark up to 10 migrations created in the same second.
Russell.
Comments and changes to this ticket
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Ben Scofield September 2nd, 2008 @ 10:35 PM
Here's a patch for the issue; it appends the microsecond time to the timestamp. Unfortunately, however, it appears that this area of railties is entirely untested, and I was sure that it would be wise to launch into a whole new suite of unit tests (though I can add those if it would help)
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Ben Scofield September 3rd, 2008 @ 06:53 PM
OK, ignore the previous patch :)
After consulting with bitsweat, I've expanded the patch for the issue by adding a new test file (rails_migration_generator_test.rb) that shows the problem.
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Brian Landau September 3rd, 2008 @ 07:07 PM
+1 This is a common issue for anyone developing new plugins/gems that use generators, or when creating personal generators.
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Russell Quinn September 4th, 2008 @ 08:31 AM
+1 Good work! It certainly seems bad that migrations are now bound to a "rate" of one per second. If the whole purpose of 2.0 migrations were to ensure uniqueness then it seems to fail usage tests.
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Ben Scofield September 4th, 2008 @ 01:48 PM
OK, after chatting with DHH and bitsweat, it appears that the appropriate action is to consolidate migrations in generators instead of trying to make the timestamps more granular. (There's also a concern that microseconds may lengthen the timestamp so that it overflows some database column constraints.)
This can be closed.
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Jeremy Kemper September 6th, 2008 @ 03:49 AM
- → State changed from “new” to “wontfix”
Cheers :) Thanks Ben.
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