Fix for NoMethodError: undefined method `supports_value_expectations?' #48
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With [this change](rspec/rspec-expectations#1139) in rspec-expectations, a call to `expect(my_object).to have(...)` is raising a `NoMethodError: undefined method `supports_value_expectations?' for <MyObject:0x000055a1b6e065c0>`. This is because ExpectationTarget calls `supports_value_expectation` here: https://github.com/rspec/rspec-expectations/blob/4e7011fe8ac68b74621336b07f894879c8da202d/lib/rspec/expectations/expectation_target.rb#L127 Which ends up being processed by `Have#method_missing` which sets `supports_value_expectations?` to @collection_name. Later in `Have#determine_collection` it tries to call `supports_value_expectations?` on my_object, which causes the NoMethodError. The fix is simple, just implement `Have#supports_value_expectations?`.
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Your link cannot be the culprit, as: So it would be useful to find out where a |
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@JonRowe That puzzled me too, initially. But what happens is that Then the NoMethodError is raised here: when it tries to send "supports_value_expectations?" to my object instance. |
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Can you please add a test case that is failing prior to the fix? |
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hah lol the matcher thinks its an expectation |
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Actually this will probably cause issues for other dynamic matchers, so I'm still wondering if this needs a fix upstream 🤔 |
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Can you please add a test case that is failing prior to the fix? |
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I still don't get what is going on 🤷 😄 |
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I'm not sure if it need specific test for this. If you just run and After this patch, all tests pass. @JonRowe If by "dynamic matchers" you mean implement Anyway, I think the fix here is still pretty reasonable and practical. |
See rspec/rspec-collection_matchers#48 If a matcher supports dynamic arbitrary methods called on it, e.g. `have_at_least(100).bucks`, it would also consider a `supports_value_expectations?` call as a dynamic part. Instead of calling `supports_*?` methods on a matcher, explicitly check if it responds to it.
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@guigs rspec/rspec-expectations#1294 should fix it for |
See rspec/rspec-collection_matchers#48 If a matcher supports dynamic arbitrary methods called on it, e.g. `have_at_least(100).bucks`, it would also consider a `supports_value_expectations?` call as a dynamic part. Instead of calling `supports_*?` methods on a matcher, explicitly check if it responds to it.
See rspec/rspec-collection_matchers#48 If a matcher supports dynamic arbitrary methods called on it, e.g. `have_at_least(100).bucks`, it would also consider a `supports_value_expectations?` call as a dynamic part. Instead of calling `supports_*?` methods on a matcher, explicitly check if it responds to it.
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@pirj I confirm that rspec/rspec-expectations#1294 also fixes the issue for me. |
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Great, thank you! |
See rspec/rspec-collection_matchers#48 If a matcher supports dynamic arbitrary methods called on it, e.g. `have_at_least(100).bucks`, it would also consider a `supports_value_expectations?` call as a dynamic part. Instead of calling `supports_*?` methods on a matcher, explicitly check if it responds to it. --- This commit was imported from rspec/rspec-expectations@c6475b5.
See rspec/rspec-collection_matchers#48 If a matcher supports dynamic arbitrary methods called on it, e.g. `have_at_least(100).bucks`, it would also consider a `supports_value_expectations?` call as a dynamic part. Instead of calling `supports_*?` methods on a matcher, explicitly check if it responds to it. --- This commit was imported from rspec/rspec-expectations@d8f272a.
In order to upgrade an application to Rails 6.1, it is necessary to use newer version of
rspec-rails4.1.0.pre, which requires rspec-expectations 3.11.0.pre.Turns out that rspec-expectations 3.11.0.pre is incompatible with current rspec-collection_matchers, because of this change, a call to
expect(my_object).to have(...)is raising aNoMethodError: undefined method 'supports_value_expectations?' for <MyObject:0x000055a1b6e065c0>.This is because
Spec::Expectations::ExpectationTargetcallsmatcher.supports_value_expectationhere.Which ends up being processed by
Have#method_missingwhich setssupports_value_expectations?to@collection_name. Then, later inHave#determine_collectionit tries to callsupports_value_expectations?onmy_object, which causes theNoMethodError.The fix is simple, just implement
Have#supports_value_expectations?.