JBuilder 2.11.3: "NoMethodError Exception: undefined method `empty?` for PG::Result"

[jtannas]

When rendering records returned by SQL JBuilder fails with

NoMethodError Exception: undefined method `empty?` for PG::Result

Simplified example:

irb(main):001:0> query_result = ActiveRecord::Base.connection.execute('SELECT * FROM users LIMIT 1')
=> #<PG::Result:0x00005594547c1120 status=PGRES_TUPLES_OK ntuples=1 nfields=31 cmd_tuples=1>
irb(main):002:0> query_result.empty?
(irb):2:in `<main>': undefined method `empty?' for #<PG::Result:0x00005594547c1120 status=PGRES_TUPLES_OK ntuples=1 nfields=31 cmd_tuples=1> (NoMethodError)

---

Ruby Version: 3.0.2p107
Jbuilder Gem Version: 2.11.3
PG Gem Version: 1.2.3

[tf]

Introduced here in #501. Related to #514.

[dhh]

cc @yuki24

[yuki24]

#524 should address this issue.

[yuki24]

Unfortunately there is a little incompatibility introduced by #501. I have removed the #empty? call, but ActionView's CollectionRenderer requires #length or #size to be implemented in Rails 6.1.

@jtannas @dhh I wonder if this is okay...

[dhh]

Not sure I fully understand the issue? The enumerable passed in much implement #length or #size?

[jtannas]

Unfortunately this is a little incompatibility Introduced by #501. I have removed the #empty? call, but ActionView's CollectionRenderer requires #length or #size to be implemented in Rails 6.1.

yeah, I'm seeing that in the test run when upgrading to 2.11.4 that it's still failing when attempting to render a PG::Result.

     Failure/Error:
       json.partial!(
         'sample_partial',
         collection: @sample_pg_result,
         as: :row,
       )

     ActionView::Template::Error:
       undefined method `size' for #<PG::Result:0x0000563f594901a8 status=PGRES_TUPLES_OK ntuples=0 nfields=7 cmd_tuples=0>
       Did you mean?  fsize

Edit: looks like there's some relevant discussion in #514 about how before it would work on anything implementing Enumerable but now additional methods are required
#514 (comment)

[yuki24]

@jtannas Apologies for the long delay, but here is a fix for the broken compatibility: #531