8a72f5c427
This commit adds the module `FromUnion`, which provides the class method
`from_union`. This simplifies the process of selecting data from the
result of a UNION, and reduces the likelihood of making mistakes. As a
result, instead of this:
union = Gitlab::SQL::Union.new([foo, bar])
Foo.from("(#{union.to_sql}) #{Foo.table_name}")
We can now write this instead:
Foo.from_union([foo, bar])
This commit also includes some changes to make this new setup work
properly. For example, a bug in Rails 4
(https://github.com/rails/rails/issues/24193) would break the use of
`from("sub-query-here").includes(:relation)` in certain cases. There was
also a CI query which appeared to repeat a lot of conditions from an
outer query on an inner query, which isn't necessary.
Finally, we include a RuboCop cop to ensure developers use this new
module, instead of using Gitlab::SQL::Union directly.
Fixes https://gitlab.com/gitlab-org/gitlab-ce/issues/51307
15 lines
305 B
Ruby
15 lines
305 B
Ruby
# frozen_string_literal: true
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class UnionFinder
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def find_union(segments, klass)
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unless klass < FromUnion
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raise TypeError, "#{klass.inspect} must include the FromUnion module"
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end
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if segments.length > 1
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klass.from_union(segments)
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else
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segments.first
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end
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end
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end
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