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POUsing rails active_record 'includes' changes results of has_many attribute accessor depending on what is included
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copied!<p>I have a <code>Project</code> and <code>User</code> model, that are connected through a <code>Permission</code> model with a has_many through, polymorphic association. The Permission table also tracks a pending status. The relevant setup is as follows:</p> <pre><code>class Project < ActiveRecord::Base has_many :permissions, as: :permissionable has_many :contributors, through: :permissions, source: :user has_many :pending_contributors, through: :permissions, source: :user, conditions: '"permissions"."accepted" = false' ... end class Permission < ActiveRecord::Base belongs_to :user belongs_to :permissionable, polymorphic: true ... end class User < ActiveRecord::Base has_many :permissions has_many :projects, through: :permissions, source: :permissionable, source_type:'Project' ... end </code></pre> <p>I'm trying to access both the contributors and pending_contributors lists on projects without causing the N+1 query issue as I render all projects. The trouble is I can't use <code>includes(:contributors, :pending_contributors)</code> because whichever one of the two includes is mentioned first is the only one that works.</p> <p>For example in my rails console:</p> <pre><code>u = User.find(2) u.projects.includes(:contributors, :pending_contributors).each do |p| puts p.contributors.map(&:id).inspect end </code></pre> <p>The result of this in my rails console is:</p> <pre><code>User Load (0.7ms) SELECT "users".* FROM "users" WHERE "users"."id" = $1 LIMIT 1 [["id", 2]] Project Load (1.3ms) SELECT "projects".* FROM "projects" INNER JOIN "permissions" ON "projects"."id" = "permissions"."permissionable_id" WHERE "permissions"."user_id" = 2 AND "permissions"."permissionable_type" = 'Project' Permission Load (1.1ms) SELECT "permissions".* FROM "permissions" WHERE "permissions"."permissionable_type" = 'Project' AND "permissions"."permissionable_id" IN (64, 56, 54, 53, 51, 50, 61, 62, 63, 57, 65, 66, 48, 49, 67, 68, 69, 70, 71, 60, 72, 16, 14, 11) User Load (0.7ms) SELECT "users".* FROM "users" WHERE "users"."id" IN (2, 18, 20, 41, 40, 3, 17, 34, 37, 39, 43, 19, 22, 42) </code></pre> <p>with the first three results being:</p> <pre><code>[2, 18, 20, 2] [2] [41, 2, 40, 18] </code></pre> <p>Now swap the order of the includes as follows:</p> <pre><code>u = User.find(2) u.projects.includes(:pending_contributors, :contributors).each do |p| puts p.contributors.map(&:id).inspect end </code></pre> <p>and suddenly the results change (yielding the results I expected) - note the permission load line, it now adds the :pending_contributors condition to that query:</p> <pre><code>User Load (0.8ms) SELECT "users".* FROM "users" WHERE "users"."id" = $1 LIMIT 1 [["id", 2]] Project Load (1.1ms) SELECT "projects".* FROM "projects" INNER JOIN "permissions" ON "projects"."id" = "permissions"."permissionable_id" WHERE "permissions"."user_id" = 2 AND "permissions"."permissionable_type" = 'Project' Permission Load (1.4ms) SELECT "permissions".* FROM "permissions" WHERE "permissions"."permissionable_type" = 'Project' AND "permissions"."permissionable_id" IN (64, 56, 54, 53, 51, 50, 61, 62, 63, 57, 65, 66, 48, 49, 67, 68, 69, 70, 71, 60, 72, 16, 14, 11) AND ("permissions"."accepted" = false) User Load (0.8ms) SELECT "users".* FROM "users" WHERE "users"."id" IN (18, 19, 40, 3, 22, 43, 42, 41, 2, 20) </code></pre> <p>and the results are:</p> <pre><code>[20] [] [41, 40, 18] </code></pre> <p>If instead of accessing pending_contributors, I access contributors, I get the same issue in reverse. I'm pretty sure this is because both pending_contributors and contributors are using the same source, but I'm not sure why this is an issue.</p> <p>Is there a way to render all projects and access contributors, and pending_contributors for each project without causing an N+1 query?</p> <p>Note: I'm on Rails 3.2.</p>

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