Reversible commands #8267

marcandre · 2012-11-19T07:39:05Z

This pull request makes the following commands reversible:

drop_table
remove_column
remove_index

It also creates the reversible command drop_join_table.

Finally, remove_columns and remove_column are no longer aliases and the interface of remove_column is changed to accept only one column (along with new arguments that are used in case of reversal).

The PR builds on #8177 (itself building on #7627), but the need they all fulfill is independent. Each PR can be accepted/rejected independently. I hope all three can be accepted as they nicely complement each other and give powerful means to create reversible migrations. The ChangeLog remains to be updated, but I'll wait until confirmation that this will be merged.

Thanks

steveklabnik · 2012-11-19T07:59:51Z

Already out of date somehow :/

marcandre · 2012-11-19T08:38:16Z

Already out of date somehow :/

I've removed the entry in the Changelog (which was only for the #7627 anyways)

When there's a decision about these 3 PRs, I'll add an entry in the Changelog.

rafaelfranca · 2012-11-19T14:46:18Z

activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb

-      def remove_column(table_name, *column_names)
-        columns_for_remove(table_name, *column_names).each {|column_name| execute "ALTER TABLE #{quote_table_name(table_name)} DROP #{column_name}" }
+      def remove_columns(table_name, *column_names)
+        raise ArgumentError.new("You must specify at least one column name. Example: remove_column(:people, :first_name)") if column_names.empty?


Should not be remove_columns here?

Good eye 🙇. Fixed

marcandre · 2012-12-19T20:01:40Z

I've updated this PR with these additional changes:

The migration generator now always generate change method
Guides: Migration and 4.0 releate notes updated to reflect these changes (see last commit)
Not directly related, but I simplified change_table (see second commit)
Made change_table reversible (as long as its block doesn't call remove, change or change_default)

tenderlove · 2012-12-19T22:26:51Z

@marcandre can you squash the commits, and I'll merge this in?

marcandre · 2012-12-19T23:12:36Z

@tenderlove Which commits should I merge? They should all stand by themselves, and many are not related at all to others

steveklabnik · 2012-12-20T02:39:59Z

@marcandre we generally squash all commits so that it's easy to backport/revert.

marcandre · 2012-12-20T04:08:13Z

@steveklabnik @tenderlove With all due respect, this is a terrible rationale. Not only is backporting/reverting rare, but git revert and git cherry-pick accept ranges of commits.

Squashing is lossy, the commits I'm submitting are atomic and make it easier to understand what's going on, for example if anyone does a git blame at some point.

Finally, if you decide to revert part of this (e.g. make drop_table revertible), you won't be able to if the commits are squashed. Similarly, the first commits are simple code improvements made because I noticed things while doing my changes.

These commits total over 1000 line changes in total, I don't see a problem in them being split in a bunch of atomic commits.

If you want me to open 13 different pull requests, I will, or maybe the commit messages should refer to this PR, but I won't squash these commits. Of course, you guys are free to do it yourself if you feel that's the way it should be.

…olumn reversible. [rails#8267]

…#8267]

…ersible [rails#8267]

marcandre · 2012-12-21T18:58:39Z

Updated commit logs with this PR number (except the first three which aren't directly related).

Had forgotten to update the ChangeLog, so this PR will probably conflict soon.

Reversible commands

carlosantoniodasilva · 2012-12-21T23:47:11Z

I'm getting these errors when running with mysql2:

  1) Error:
test_migrate_revert_by_part(ActiveRecord::InvertibleMigrationTest):
ActiveRecord::StatementInvalid: Mysql2::Error: SAVEPOINT active_record_1 does not exist: ROLLBACK TO SAVEPOINT active_record_1

(there are a bunch of apparently related errors and travis build page for mysql/mysql2 doesn't seem to be loading)

Also, travis reported a failing test in railties. And another fix I already commited in 68e91da...4da76d7.

@marcandre would you mind taking a look at the mysql failures? I think I'll just be able to continue working on it tomorrow, so if you can, that'd be very welcome. Thanks.

marcandre · 2012-12-22T00:50:16Z

@carlosantoniodasilva Thanks for the fixes. The railties error is trivial (string vs symbol), but I'm not sure what's up with the mysql errors. Probably related to using transaction in the migration?

I'll be able to check that first thing tomorrow.

carlosantoniodasilva · 2012-12-22T00:54:51Z

@marcandre it seems so, somehow related to the reversible command (that has a transaction block on it). If I skip that test I sent before, everything seems to be fine.

marcandre · 2012-12-22T06:48:17Z

@carlosantoniodasilva Right. I still can't imagine why it causes a problem on mysql, but I'll just not use transaction at all. Actually I can probably use send something :tap instead. Anyways, I'll run the test when I'm home tomorrow and send a PR.

carlosantoniodasilva · 2012-12-22T10:25:09Z

@marcandre thanks, let me know if you find anything or need any help.

josevalim · 2012-12-22T21:02:25Z

This PR broke the build: https://travis-ci.org/rails/rails/jobs/3781822

* Fix Migration#reversible by not using `transaction`. * Adapt mysql adapter to updated api for remove_column * Update test after aedcd68

marcandre · 2012-12-23T09:58:50Z

@josevalim Should all be fixed by [#8588]

`def remove_columns(table_name, *column_names)` is defined in ActiveRecord::ConnectionAdapters::SchemaStatements, which does not require Oracle enhanced specific implementation. `def remove_column(table_name, column_name, type = nil, options = {})` ignores `type` and `options` arguments to avoid ORA-00904 errors See rails/rails#8267 for Rails change. This commit should not backport into release14 branch.

seanlinsley · 2014-12-15T21:46:49Z

remove_index is reversible when you provide the :column option:

def change
  remove_index :users, column: :email
end

But when providing the column in the normal way,

def change
  remove_index :users, :email
end

you get this error message:

remove_index is only reversible if given a :column option.

Is this by design, or should I create a ticket / PR for it?

marcandre · 2014-12-15T22:37:50Z

@seanlinsley Definitely not by design!

Issue or PR would be good (I don't have time now), please cc me though 😄

marcandre mentioned this pull request Nov 19, 2012

Migration revert #7627

Closed

rafaelfranca reviewed Nov 19, 2012
View reviewed changes

marcandre mentioned this pull request Dec 19, 2012

Migration reversible #8177

Closed

marcandre added 16 commits December 21, 2012 13:54

Simplify change_table and avoid duplicated logic

b045804

Simple replacement of variable name for consistency

29ed612

Split ridiculously long line

740dbf8

Allow reverting of migration commands with Migration#revert [rails#8267]

d327c18

Extract exec_migration [rails#8267]

24653c9

Allow revert of whole migration [rails#8267]

65e154f

Add Migration#reversible for reversible data operations [rails#8267]

99770e4

Add drop_join_table [rails#8267]

bd155d2

Make drop_table reversible [rails#8267]

af871a0

Differentiate between remove_column and remove_columns. Make remove_c…

e28ddea

…olumn reversible. [rails#8267]

Make remove_index reversible [rails#8267]

3132324

Factorize methods that are easily reversible [rails#8267]

7204d3c

Migration generators use change even for destructive methods [rails…

aedcd68

…#8267]

Make change_table reversible when possible [rails#8267]

e43e8e2

Make execute, change_column and remove_columns methods actually irrev…

06c7ba8

…ersible [rails#8267]

Update Migration and 4.0 Release Guides, Changelogs [rails#8267]

a81845f

tenderlove added a commit that referenced this pull request Dec 21, 2012

Merge pull request #8267 from marcandre/reversible_drop_table_etc

68e91da

Reversible commands

tenderlove merged commit 68e91da into rails:master Dec 21, 2012

marcandre mentioned this pull request Dec 22, 2012

Fix Migration#reversible by not using transaction. #8588

Merged

marcandre added a commit to marcandre/rails that referenced this pull request Dec 23, 2012

Fixes for PR [rails#8267]

a4932d6

* Fix Migration#reversible by not using `transaction`. * Adapt mysql adapter to updated api for remove_column * Update test after aedcd68

rafaelfranca mentioned this pull request Apr 15, 2013

reversible remove_column in migrations #10219

Closed

zmoazeni mentioned this pull request May 2, 2013

Reversing remove_index fails with "no implicit conversion of Symbol into Integer" #10419

Closed

yahonda mentioned this pull request Nov 29, 2013

Support remove_columns rsim/oracle-enhanced#377

Merged

marcandre deleted the reversible_drop_table_etc branch September 25, 2022 02:39

Reversible commands #8267

Reversible commands #8267

marcandre commented Nov 19, 2012

steveklabnik commented Nov 19, 2012

marcandre commented Nov 19, 2012

rafaelfranca Nov 19, 2012

marcandre Nov 19, 2012

marcandre commented Dec 19, 2012

tenderlove commented Dec 19, 2012

marcandre commented Dec 19, 2012

steveklabnik commented Dec 20, 2012

marcandre commented Dec 20, 2012

marcandre commented Dec 21, 2012

carlosantoniodasilva commented Dec 21, 2012

marcandre commented Dec 22, 2012

carlosantoniodasilva commented Dec 22, 2012

marcandre commented Dec 22, 2012

carlosantoniodasilva commented Dec 22, 2012

josevalim commented Dec 22, 2012

marcandre commented Dec 23, 2012

seanlinsley commented Dec 15, 2014

marcandre commented Dec 15, 2014

Reversible commands #8267

Reversible commands #8267

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marcandre commented Nov 19, 2012

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