Check Encodings before calling force_encoding in Addressable::URI

[ACBullen]

Reopening this pr with just the minimum changes to fix the issue blocking our use of the current version.

This is a quick fix to this issue, just adding in an extra check to avoid mutating strings when it isn't necessary

Close #254

[dentarg]

Reopening this pr with just the minimum changes to fix the issue blocking our use of the current version.

I'm curious, what are the issue you are facing with the current version?

This is a quick fix to this issue, just adding in an extra check to avoid mutating strings when it isn't necessary

#254 is about constants, but this PR only touches instance variables, so I don't think it is the same.

[ACBullen]

The issue with constants is sort of an extension of the issue we have right now since we are normalizing the Addressable::URI object and then deep freezing. Even if the path or other part of the uri doesn't map to a constant, we are marking all of those strings as intended to be immutable. Since the force_encoding runs every time we try to reference parts of the parsed and normalized URI, this causes the same RuntimeError: can't modify frozen String to return.

Without this check, after the strings go through normalization, they are in their final state and do not mutate unless something tries to reassign one of the.

[dentarg]

Got it, thanks.

I think we need to add tests for this.

[baseballlover723]

@dentarg I have rebased and updated this PR. Let me know if theres anything else you want me to change.

[dentarg]

FrozenError only exist in Ruby 2.5 and newer (I just learned this too). Sounds like it was RuntimeError before: jruby/jruby#5106

Hence the test failures. Do you mind addressing this?

[baseballlover723]

I just pushed some changes

[baseballlover723]

@dentarg This is ready for review again

[sporkmonger]

I'd prefer to have this test not care at all which error type is raised.

[dentarg]

Not sure I'm following... it says should not allow destructive operations and we expect @uri.normalize! to raise RuntimeError/FrozenError (can't modify frozen String). Is that because you shouldn't be able to use #normalize! on a frozen Addressable::URI? Maybe we can make that even more clear in the test? (The @uri.freeze happens way up in the before block so it is easy to miss)

Maybe Addressable::URI#normalize! should detect that the URI is frozen and raise an error defined by Addressable? (FrozenURIError perhaps?)

---

Ah, this particular spec doesn't test the changes made in this branch, I ran this against Addressable 2.8.0

# Ruby 2.4.3

irb(main):005:0* @uri = Addressable::URI.parse("http://user:[email protected]:8080/path?query=value#fragment")
=> #<Addressable::URI:0x3ff6e204dd78 URI:http://user:[email protected]:8080/path?query=value#fragment>
irb(main):006:0> @uri.freeze
=> #<Addressable::URI:0x3ff6e204dd78 URI:http://user:[email protected]:8080/path?query=value#fragment>
irb(main):007:0> @uri.normalize!
RuntimeError: can't modify frozen Addressable::URI
	from /Users/dentarg/.gem/ruby/2.4.3/gems/addressable-2.8.0/lib/addressable/uri.rb:2518:in `remove_instance_variable'
	from /Users/dentarg/.gem/ruby/2.4.3/gems/addressable-2.8.0/lib/addressable/uri.rb:2518:in `block in replace_self'
	from /Users/dentarg/.gem/ruby/2.4.3/gems/addressable-2.8.0/lib/addressable/uri.rb:2516:in `each'
	from /Users/dentarg/.gem/ruby/2.4.3/gems/addressable-2.8.0/lib/addressable/uri.rb:2516:in `replace_self'
	from /Users/dentarg/.gem/ruby/2.4.3/gems/addressable-2.8.0/lib/addressable/uri.rb:2211:in `normalize!'
	from (irb):7
	from /Users/dentarg/.rubies/2.4.3/bin/irb:11:in `<main>'

# Ruby 3.1.2

irb(main):005:0> @uri = Addressable::URI.parse("http://user:[email protected]:8080/path?query=value#fragment")
=> #<Addressable::URI:0xb43c URI:http://user:[email protected]:8080/path?query=value#fragment>
irb(main):006:0>
irb(main):007:0> @uri.freeze
=> #<Addressable::URI:0xb43c URI:http://user:[email protected]:8080/path?query=value#fragment>
irb(main):008:0> @uri.normalize!
/Users/dentarg/.gem/ruby/3.1.2/gems/addressable-2.8.0/lib/addressable/uri.rb:2518:in `remove_instance_variable': can't modify frozen Addressable::URI: #<Addressable::URI:0xb43c URI:http://user:[email protected]:8080/path?query=value#fragment> (FrozenError)
	from /Users/dentarg/.gem/ruby/3.1.2/gems/addressable-2.8.0/lib/addressable/uri.rb:2518:in `block in replace_self'
	from /Users/dentarg/.gem/ruby/3.1.2/gems/addressable-2.8.0/lib/addressable/uri.rb:2516:in `each'
	from /Users/dentarg/.gem/ruby/3.1.2/gems/addressable-2.8.0/lib/addressable/uri.rb:2516:in `replace_self'
	from /Users/dentarg/.gem/ruby/3.1.2/gems/addressable-2.8.0/lib/addressable/uri.rb:2211:in `normalize!'
	from (irb):8:in `<main>'
	from /Users/dentarg/.rubies/3.1.2/lib/ruby/gems/3.1.0/gems/irb-1.4.1/exe/irb:11:in `<top (required)>'
	from /Users/dentarg/.rubies/3.1.2/bin/irb:25:in `load'
	from /Users/dentarg/.rubies/3.1.2/bin/irb:25:in `<main>'

Perhaps we shouldn't change this behaviour as I suggested above

---

@sporkmonger should we just check error message? Expect can't modify frozen Addressable::URI. Those can change from Ruby to Ruby version too, but probably unlikely in this case IMHO.

[sporkmonger]

Mostly I'd prefer to have the test make the same checks regardless of Ruby version. If the error message is consistent between versions but the type is not, it seems fine to check the error message, but if that's inconsistent too, I think it's fine to verify that an error, any error, has been thrown.

I think I'd rather not do a custom error type because I think if we did a custom type it should probably inherit from FrozenError on versions of Ruby that have it, and that just shifts the problem out of the tests and into the library itself. I'm not sure that's an improvement.

[dentarg]

We can have the test make the same checks regardless of Ruby version. If we look at the hierarchy of exceptions at https://ruby-doc.org/core-2.6.5/Exception.html we can see that FrozenError is a subclass of RuntimeError. That should never change really. We can use #is_a? and always check if it is a RuntimeError:

irb(main):007:1* ex = begin
irb(main):008:1*   raise FrozenError, "can't modify frozen String"
irb(main):009:1* rescue => e
irb(main):010:1*   e
irb(main):011:0> end
=> #<FrozenError: can't modify frozen String>
irb(main):012:0> ex.inspect
=> "#<FrozenError: can't modify frozen String>"
irb(main):013:0> ex.is_a?(RuntimeError)
=> true

[dentarg]

(We don't need to check the message)

[baseballlover723]

Are there any other changes required? I've implemented the above changes.

[dentarg]

Looks good now, thanks!

The requested changed has been made