Alternate fix for #336. We went with #347 instead because the solution
in this commit didn't work with Rails 4.2. Since we are no longer
supporting Rails 4.2, I think this is a better approach.
The original problem looked like this:
Rails runs all of the initializers
1. Run the ["factory_bot.set_factory_paths"][set_factory_paths]
initializer
2. Run the ["factory_bot.register_reloader"][register_reloader]
initializer, which sets up a [prepare callback][]
3. Run the [`:run_prepare_callbacks`][] initializer
4. This triggers the factory_bot [prepare callback][], which causes
factory\_bot to [reload][]
Rails runs `after_initialize` callbacks
1. [I18n initializes]
2. factory\_bot [reloads again][] as described in #334
Triggering the first factory_bot reload before initializing I18n could
cause an error in some cases.
We avoided the problem in #347 by adding a conditional to skip reloading
factory_bot before the application has initialized.
This commit, on the other hand, moves factory_bot reloading from a
prepare callback into an `after_initialize` callback. The initialization
process is now simplified to:
Rails runs all of the initializers
1. Run the ["factory_bot.set_factory_paths"][set_factory_paths]
2. Run the [`:run_prepare_callbacks`][] initializer, which no longer
involves factory_bot
Rails runs `after_intialize` callbacks
1. [I18n initializes]
2. factory_bot loads definitions for the first time. It then runs the
reloader to set up the prepare callback to reload factory_bot when the
application reloads (for example by calling `reload!` in the console),
and to register the reloader to trigger reloads when any factory_bot
definition files change.
[set_factory_paths]: 3815aae2b9/lib/factory_bot_rails/railtie.rb (L17-L19)
[register_reloader]: 3815aae2b9/lib/factory_bot_rails/railtie.rb (L21-L23)
[prepare callback]: https://github.com/thoughtbot/factory_bot_rails/blob/master/lib/factory_bot_rails/reloader.rb#L34-L36
[`:run_prepare_callbacks`]: https://github.com/rails/rails/blob/5-2-stable/railties/lib/rails/application/finisher.rb#L62-L64
[reload]: https://github.com/thoughtbot/factory_bot_rails/blob/master/lib/factory_bot_rails/reloader.rb#L24-L26
[I18n initializes]: 13e2102517/activesupport/lib/active_support/i18n_railtie.rb (L16-L20)
[reloads again]: https://github.com/thoughtbot/factory_bot_rails/blob/master/lib/factory_bot_rails/railtie.rb#L25-L27
If all the paths specified in `FactoryBot.definition_file_paths` do not
exist, an empty array is passed to the reloader.
If an empty array is specified, reloader passes it to `Listen.to` as it
is. This causes the application root to be watched and `node_modules` to
become a target of listening.
The behavior when an empty array is passed to reloader depends on the
Rails side. Fixes to not register a reloader when file paths do not exist
consistent behavior regardless of Rails side.
Fixes#328.
Closes#236
This commit uses ActiveSupport's FileUpdateChecker to allow reloading
FactoryBot of definitions whenever a file in
`FactoryBot.definition_file_paths` gets updated.
This is similar to reloading for
[I18n](ced104d579/activesupport/lib/active_support/i18n_railtie.rb (L60-L70))
and [react rails](83b6175460/lib/react/rails/railtie.rb (L35-L41))
This allows us to get rid of any Spring-specific logic in the railtie,
since [Spring hooks into the application
reloader](0c711ff10b/lib/spring/application.rb (L161)).
This partly solves #211, since we no longer call `FactoryBot.reload` at
all in `after_initialize`. Instead, we will only call it when one of the
files in `definition_file_paths` gets updated. I say it partly
solves #211 because once a definition file gets updated, reloading
would still give warnings about redefining any constants in the
definition files. I wonder how common it is to define constants in the
same file as factory definitions. It's probably better to keep constants
in the autoload path, allowing Rails to handle unloading and reloading
them in development. I would want to see some specific examples before
worrying too much about it.
I would also like to offer a better way to configure the definition file
paths (see #165 and #166) and possibly an option to opt out of loading
definitions at all (could help with issues like #192).
A couple of quirks here:
* the to_prepare block could potentially get
[called multiple times](https://github.com/rails/rails/issues/28108).
It shouldn't matter, since `execute_if_updated` is a no-op if no
updates have been made.
* I noticed that the first time I call `reload!` in the console the
factory definitions get reloaded even when I made no updates to the
definition files. I think it is related to
[this](f7c5a8ce26/activesupport/lib/active_support/evented_file_update_checker.rb (L18)). After the first call
`reload!` works as expected, only reloading the factory definitions
if the definition files were updated.
* Rails uses execute rather than execute_if_updated for the
[route
reloader](https://github.com/rails/rails/blob/master/railties/lib/rails/application/finisher.rb#L133)
and for the [watchable file
reloader](https://github.com/rails/rails/blob/master/railties/lib/rails/application/finisher.rb#L173).
This means that changes to factory definitions will cause reloading of
the whole application. I think this is fine.
