AE
Ash Elixir•9h ago
Failz

ash_double_entry and updating transfers

I see a unit test that is capable of updating a transfer. However I cannot get it to work and see this error. 
* ** (CaseClauseError) no case clause matching: {:error, "Cannot destroy a transfer atomically if balances must be destroyed manually, or if balance is being updated"}
* ** (CaseClauseError) no case clause matching: {:error, "Cannot destroy a transfer atomically if balances must be destroyed manually, or if balance is being updated"}
I am using Postgres (16.1) and saw this in the docs: 
transfer do
    # configure the other resources it will interact with
    account_resource YourApp.Ledger.Account
    balance_resource YourApp.Ledger.Balance

    # you only need this if you are using `postgres`
    # and so cannot add the `references` block shown below

    # destroy_balances? true
  end
transfer do
    # configure the other resources it will interact with
    account_resource YourApp.Ledger.Account
    balance_resource YourApp.Ledger.Balance

    # you only need this if you are using `postgres`
    # and so cannot add the `references` block shown below

    # destroy_balances? true
  end
cascading destroys

If you are not using a data layer capable of automatic cascade deletion, you must add destroy_balances? true to the transfer resource! We do this with the references block in ash_postgres as shown above.
cascading destroys

If you are not using a data layer capable of automatic cascade deletion, you must add destroy_balances? true to the transfer resource! We do this with the references block in ash_postgres as shown above.
I've played with both of these settings but still come up against the error I posted above. The mention of these two settings is confusing. Postgres is capable of "automatic cascade deletion", no? What am I missing? Note: There's no ash_double_entry tag.
17 Replies
ZachDaniel
ZachDaniel•9h ago
Hm....something does seem strange there. Is that case clause error happening somewhere internally? In what way are you updating the transfer? Might need to see a repro
Failz
FailzOP•9h ago
ZachDaniel
ZachDaniel•9h ago
Latest version of everything?
Failz
FailzOP•8h ago
vscode ➜ /workspaces/yakgo.money (main ✗) $ mix hex.outdated
Dependency                  Current  Latest  Status               
ash                         3.5.12   3.5.12  Up-to-date           
ash_admin                   0.13.5   0.13.5  Up-to-date           
ash_authentication          4.8.7    4.8.7   Up-to-date           
ash_authentication_phoenix  2.7.0    2.7.0   Up-to-date           
ash_double_entry            1.0.14   1.0.14  Up-to-date           
ash_money                   0.2.0    0.2.0   Up-to-date           
ash_paper_trail             0.5.3    0.5.3   Up-to-date           
ash_phoenix                 2.3.2    2.3.2   Up-to-date           
ash_postgres                2.5.22   2.5.22  Up-to-date           
bandit                      1.6.11   1.6.11  Up-to-date           
bcrypt_elixir               3.3.2    3.3.2   Up-to-date           
dns_cluster                 0.1.3    0.2.0   Update not possible  
ecto_sql                    3.12.1   3.12.1  Up-to-date           
esbuild                     0.9.0    0.9.0   Up-to-date           
ex_money_sql                1.11.0   1.11.0  Up-to-date           
finch                       0.19.0   0.19.0  Up-to-date           
floki                       0.37.1   0.37.1  Up-to-date           
gettext                     0.26.2   0.26.2  Up-to-date           
igniter                     0.6.2    0.6.2   Up-to-date           
jason                       1.4.4    1.4.4   Up-to-date           
live_debugger               0.2.3    0.2.3   Up-to-date           
phoenix                     1.7.21   1.7.21  Up-to-date           
phoenix_ecto                4.6.4    4.6.4   Up-to-date           
phoenix_html                4.2.1    4.2.1   Up-to-date           
phoenix_live_dashboard      0.8.7    0.8.7   Up-to-date           
phoenix_live_reload         1.6.0    1.6.0   Up-to-date           
phoenix_live_view           1.0.12   1.0.12  Up-to-date           
picosat_elixir              0.2.3    0.2.3   Up-to-date           
postgrex                    0.20.0   0.20.0  Up-to-date           
sourceror                   1.10.0   1.10.0  Up-to-date           
swoosh                      1.19.1   1.19.1  Up-to-date           
tailwind                    0.2.4    0.3.1   Update not possible  
telemetry_metrics           1.1.0    1.1.0   Up-to-date           
telemetry_poller            1.2.0    1.2.0   Up-to-date           
tidewave                    0.1.6    0.1.7   Update possible
vscode ➜ /workspaces/yakgo.money (main ✗) $ mix hex.outdated
Dependency                  Current  Latest  Status               
ash                         3.5.12   3.5.12  Up-to-date           
ash_admin                   0.13.5   0.13.5  Up-to-date           
ash_authentication          4.8.7    4.8.7   Up-to-date           
ash_authentication_phoenix  2.7.0    2.7.0   Up-to-date           
ash_double_entry            1.0.14   1.0.14  Up-to-date           
ash_money                   0.2.0    0.2.0   Up-to-date           
ash_paper_trail             0.5.3    0.5.3   Up-to-date           
ash_phoenix                 2.3.2    2.3.2   Up-to-date           
ash_postgres                2.5.22   2.5.22  Up-to-date           
bandit                      1.6.11   1.6.11  Up-to-date           
bcrypt_elixir               3.3.2    3.3.2   Up-to-date           
dns_cluster                 0.1.3    0.2.0   Update not possible  
ecto_sql                    3.12.1   3.12.1  Up-to-date           
esbuild                     0.9.0    0.9.0   Up-to-date           
ex_money_sql                1.11.0   1.11.0  Up-to-date           
finch                       0.19.0   0.19.0  Up-to-date           
floki                       0.37.1   0.37.1  Up-to-date           
gettext                     0.26.2   0.26.2  Up-to-date           
igniter                     0.6.2    0.6.2   Up-to-date           
jason                       1.4.4    1.4.4   Up-to-date           
live_debugger               0.2.3    0.2.3   Up-to-date           
phoenix                     1.7.21   1.7.21  Up-to-date           
phoenix_ecto                4.6.4    4.6.4   Up-to-date           
phoenix_html                4.2.1    4.2.1   Up-to-date           
phoenix_live_dashboard      0.8.7    0.8.7   Up-to-date           
phoenix_live_reload         1.6.0    1.6.0   Up-to-date           
phoenix_live_view           1.0.12   1.0.12  Up-to-date           
picosat_elixir              0.2.3    0.2.3   Up-to-date           
postgrex                    0.20.0   0.20.0  Up-to-date           
sourceror                   1.10.0   1.10.0  Up-to-date           
swoosh                      1.19.1   1.19.1  Up-to-date           
tailwind                    0.2.4    0.3.1   Update not possible  
telemetry_metrics           1.1.0    1.1.0   Up-to-date           
telemetry_poller            1.2.0    1.2.0   Up-to-date           
tidewave                    0.1.6    0.1.7   Update possible
where does :skip_balance_updates come from? I don't see this in my IO.inspect output 
changeset.context[:ash_double_entry][:skip_balance_updates]
changeset.context[:ash_double_entry][:skip_balance_updates]
ZachDaniel
ZachDaniel•8h ago
You're right, it looks like possibly something that was supposed to be setting this context was removed and so is preventing essentially the cascading balance updates required actually, nvm the amounts shouldn't be changing on future transfers, that stays the same okay, I have a thought can you try main of ash_double_entry? Its just returning the wrong format {:error, ...} should be {:not_atomic, ...} The action can be done, just not atomically (because it requires multiple queries)
Failz
FailzOP•8h ago
do I need to set either of these? 
# balance.ex
postgres do
    table "balances"
    repo YourApp.Repo

    references do
      reference :transfer, on_delete: :delete
    end
  end

# or
# transfer.ex
transfer do
    account_resource App.Ledger.Account
    balance_resource App.Ledger.Balance
    destroy_balances? true
  end
# balance.ex
postgres do
    table "balances"
    repo YourApp.Repo

    references do
      reference :transfer, on_delete: :delete
    end
  end

# or
# transfer.ex
transfer do
    account_resource App.Ledger.Account
    balance_resource App.Ledger.Balance
    destroy_balances? true
  end
ZachDaniel
ZachDaniel•8h ago
Just the references
Failz
FailzOP•8h ago
now seeing the :not_atomic coming back 
vscode ➜ /workspaces/yakgo.money (main ✗) $ iex -S mix
Erlang/OTP 27 [erts-15.2.3] [source] [64-bit] [smp:4:4] [ds:4:4:10] [async-threads:1] [jit]

Interactive Elixir (1.18.3) - press Ctrl+C to exit (type h() ENTER for help)
iex(1)> transfer = App.Ledger.get_transfer!("01JW3TNT6M4PW7QWSTY5KSPT19")
[debug] %Postgrex.Query{ref: nil, name: "ecto_1154", statement: "SELECT l0.\"id\", l0.\"timestamp\", l0.\"amount\", l0.\"updated_at\", l0.\"inserted_at\", l0.\"from_account_id\", l0.\"to_account_id\" FROM \"ledger_transfers\" AS l0 WHERE (l0.\"id\"::bytea::bytea = $1::bytea::bytea)", param_oids: nil, param_formats: nil, param_types: nil, columns: nil, result_oids: nil, result_formats: nil, result_types: nil, types: nil, cache: :reference} uses unknown oid(s) 16792forcing us to reload type information from the database. This is expected behaviour whenever you migrate your database.
[debug] QUERY OK source="ledger_transfers" db=0.2ms queue=3.0ms idle=315.9ms
SELECT l0."id", l0."timestamp", l0."amount", l0."updated_at", l0."inserted_at", l0."from_account_id", l0."to_account_id" FROM "ledger_transfers" AS l0 WHERE (l0."id"::bytea::bytea = $1::bytea::bytea) ["01JW3TNT6M4PW7QWSTY5KSPT19"]
↳ anonymous fn/3 in AshPostgres.DataLayer.run_query/2, at: lib/data_layer.ex:786
%App.Ledger.Transfer{
  balances: #Ash.NotLoaded<:relationship, field: :balances>,
  to_account: #Ash.NotLoaded<:relationship, field: :to_account>,
  from_account: #Ash.NotLoaded<:relationship, field: :from_account>,
  __meta__: #Ecto.Schema.Metadata<:loaded, "ledger_transfers">,
  id: "01JW3TNT6M4PW7QWSTY5KSPT19",
  amount: Money.new(:USD, "20"),
  inserted_at: ~U[2025-05-25 13:38:50.709890Z],
  updated_at: ~U[2025-05-25 13:38:50.709890Z],
  timestamp: ~U[2025-05-25 13:38:50.709837Z],
  from_account_id: "0197078c-7b11-7b5f-a00b-1ec0996ba0b8",
  to_account_id: "0197078f-1092-7c1e-88e9-1cf553432e7a"
}
iex(2)> App.Ledger.update_transfer(transfer, %{amount: Money.new(10, :USD)})
changeset: #Ash.Changeset<
  domain: App.Ledger,
  action_type: :update,
  action: :update,
  attributes: %{amount: Money.new(:USD, "10")},
  relationships: %{},
  errors: [],
  data: %App.Ledger.Transfer{
    balances: #Ash.NotLoaded<:relationship, field: :balances>,
    to_account: #Ash.NotLoaded<:relationship, field: :to_account>,
    from_account: #Ash.NotLoaded<:relationship, field: :from_account>,
    __meta__: #Ecto.Schema.Metadata<:loaded, "ledger_transfers">,
    id: "01JW3TNT6M4PW7QWSTY5KSPT19",
    amount: Money.new(:USD, "20"),
    inserted_at: ~U[2025-05-25 13:38:50.709890Z],
    updated_at: ~U[2025-05-25 13:38:50.709890Z],
    timestamp: ~U[2025-05-25 13:38:50.709837Z],
    from_account_id: "0197078c-7b11-7b5f-a00b-1ec0996ba0b8",
    to_account_id: "0197078f-1092-7c1e-88e9-1cf553432e7a"
  },
  valid?: true
>
opts: []
context: %Ash.Resource.Change.Context{
  actor: nil,
  tenant: nil,
  authorize?: true,
  tracer: nil,
  bulk?: false
}
{:error,
 %Ash.Error.framework{
   errors: [
     %Ash.Error.Framework.MustBeAtomic{
       resource: App.Ledger.Transfer,
       action: :update,
       reason: "Cannot destroy a transfer atomically if balances must be destroyed manually, or if balance is being updated",
       splode: Ash.Error,
       bread_crumbs: [],
       vars: [],
       path: [],
       stacktrace: #Splode.Stacktrace<>,
       class: :framework
     }
   ]
 }}
iex(3)>
vscode ➜ /workspaces/yakgo.money (main ✗) $ iex -S mix
Erlang/OTP 27 [erts-15.2.3] [source] [64-bit] [smp:4:4] [ds:4:4:10] [async-threads:1] [jit]

Interactive Elixir (1.18.3) - press Ctrl+C to exit (type h() ENTER for help)
iex(1)> transfer = App.Ledger.get_transfer!("01JW3TNT6M4PW7QWSTY5KSPT19")
[debug] %Postgrex.Query{ref: nil, name: "ecto_1154", statement: "SELECT l0.\"id\", l0.\"timestamp\", l0.\"amount\", l0.\"updated_at\", l0.\"inserted_at\", l0.\"from_account_id\", l0.\"to_account_id\" FROM \"ledger_transfers\" AS l0 WHERE (l0.\"id\"::bytea::bytea = $1::bytea::bytea)", param_oids: nil, param_formats: nil, param_types: nil, columns: nil, result_oids: nil, result_formats: nil, result_types: nil, types: nil, cache: :reference} uses unknown oid(s) 16792forcing us to reload type information from the database. This is expected behaviour whenever you migrate your database.
[debug] QUERY OK source="ledger_transfers" db=0.2ms queue=3.0ms idle=315.9ms
SELECT l0."id", l0."timestamp", l0."amount", l0."updated_at", l0."inserted_at", l0."from_account_id", l0."to_account_id" FROM "ledger_transfers" AS l0 WHERE (l0."id"::bytea::bytea = $1::bytea::bytea) ["01JW3TNT6M4PW7QWSTY5KSPT19"]
↳ anonymous fn/3 in AshPostgres.DataLayer.run_query/2, at: lib/data_layer.ex:786
%App.Ledger.Transfer{
  balances: #Ash.NotLoaded<:relationship, field: :balances>,
  to_account: #Ash.NotLoaded<:relationship, field: :to_account>,
  from_account: #Ash.NotLoaded<:relationship, field: :from_account>,
  __meta__: #Ecto.Schema.Metadata<:loaded, "ledger_transfers">,
  id: "01JW3TNT6M4PW7QWSTY5KSPT19",
  amount: Money.new(:USD, "20"),
  inserted_at: ~U[2025-05-25 13:38:50.709890Z],
  updated_at: ~U[2025-05-25 13:38:50.709890Z],
  timestamp: ~U[2025-05-25 13:38:50.709837Z],
  from_account_id: "0197078c-7b11-7b5f-a00b-1ec0996ba0b8",
  to_account_id: "0197078f-1092-7c1e-88e9-1cf553432e7a"
}
iex(2)> App.Ledger.update_transfer(transfer, %{amount: Money.new(10, :USD)})
changeset: #Ash.Changeset<
  domain: App.Ledger,
  action_type: :update,
  action: :update,
  attributes: %{amount: Money.new(:USD, "10")},
  relationships: %{},
  errors: [],
  data: %App.Ledger.Transfer{
    balances: #Ash.NotLoaded<:relationship, field: :balances>,
    to_account: #Ash.NotLoaded<:relationship, field: :to_account>,
    from_account: #Ash.NotLoaded<:relationship, field: :from_account>,
    __meta__: #Ecto.Schema.Metadata<:loaded, "ledger_transfers">,
    id: "01JW3TNT6M4PW7QWSTY5KSPT19",
    amount: Money.new(:USD, "20"),
    inserted_at: ~U[2025-05-25 13:38:50.709890Z],
    updated_at: ~U[2025-05-25 13:38:50.709890Z],
    timestamp: ~U[2025-05-25 13:38:50.709837Z],
    from_account_id: "0197078c-7b11-7b5f-a00b-1ec0996ba0b8",
    to_account_id: "0197078f-1092-7c1e-88e9-1cf553432e7a"
  },
  valid?: true
>
opts: []
context: %Ash.Resource.Change.Context{
  actor: nil,
  tenant: nil,
  authorize?: true,
  tracer: nil,
  bulk?: false
}
{:error,
 %Ash.Error.framework{
   errors: [
     %Ash.Error.Framework.MustBeAtomic{
       resource: App.Ledger.Transfer,
       action: :update,
       reason: "Cannot destroy a transfer atomically if balances must be destroyed manually, or if balance is being updated",
       splode: Ash.Error,
       bread_crumbs: [],
       vars: [],
       path: [],
       stacktrace: #Splode.Stacktrace<>,
       class: :framework
     }
   ]
 }}
iex(3)>
I added back in the inspects
ZachDaniel
ZachDaniel•8h ago
update_transfer is defined by you right?
Failz
FailzOP•8h ago
correct: 
defmodule App.Ledger do
  use Ash.Domain,
    otp_app: :app,
    extensions: [AshPhoenix]

  resources do
    resource App.Ledger.Account do
      define :list_accounts, action: :read
      define :get_account, action: :read, get_by: [:id]
      define :open_account, action: :open
      define :update_account, action: :update
      define :delete_account, action: :destroy
    end

    resource App.Ledger.Balance

    resource App.Ledger.Transfer do
      define :list_transfers, action: :read
      define :get_transfer, action: :read, get_by: [:id]
      define :create_transfer, action: :transfer
      define :update_transfer, action: :update
    end
  end
end
defmodule App.Ledger do
  use Ash.Domain,
    otp_app: :app,
    extensions: [AshPhoenix]

  resources do
    resource App.Ledger.Account do
      define :list_accounts, action: :read
      define :get_account, action: :read, get_by: [:id]
      define :open_account, action: :open
      define :update_account, action: :update
      define :delete_account, action: :destroy
    end

    resource App.Ledger.Balance

    resource App.Ledger.Transfer do
      define :list_transfers, action: :read
      define :get_transfer, action: :read, get_by: [:id]
      define :create_transfer, action: :transfer
      define :update_transfer, action: :update
    end
  end
end
and 
defmodule App.Ledger.Transfer do
  use Ash.Resource,
    domain: Elixir.App.Ledger,
    data_layer: AshPostgres.DataLayer,
    extensions: [AshDoubleEntry.Transfer]

  transfer do
    account_resource App.Ledger.Account
    balance_resource App.Ledger.Balance
  end

  postgres do
    table "ledger_transfers"
    repo App.Repo
  end

  actions do
    defaults [:read]

    create :transfer do
      accept [:amount, :timestamp, :from_account_id, :to_account_id]
    end

    update :update do
      accept [:amount]
    end
  end

  attributes do
    attribute :id, AshDoubleEntry.ULID do
      primary_key? true
      allow_nil? false
      default &AshDoubleEntry.ULID.generate/0
    end

    attribute :amount, :money do
      allow_nil? false
    end

    timestamps()
  end

  relationships do
    belongs_to :from_account, App.Ledger.Account do
      attribute_writable? true
    end

    belongs_to :to_account, App.Ledger.Account do
      attribute_writable? true
    end

    has_many :balances, App.Ledger.Balance
  end
end
defmodule App.Ledger.Transfer do
  use Ash.Resource,
    domain: Elixir.App.Ledger,
    data_layer: AshPostgres.DataLayer,
    extensions: [AshDoubleEntry.Transfer]

  transfer do
    account_resource App.Ledger.Account
    balance_resource App.Ledger.Balance
  end

  postgres do
    table "ledger_transfers"
    repo App.Repo
  end

  actions do
    defaults [:read]

    create :transfer do
      accept [:amount, :timestamp, :from_account_id, :to_account_id]
    end

    update :update do
      accept [:amount]
    end
  end

  attributes do
    attribute :id, AshDoubleEntry.ULID do
      primary_key? true
      allow_nil? false
      default &AshDoubleEntry.ULID.generate/0
    end

    attribute :amount, :money do
      allow_nil? false
    end

    timestamps()
  end

  relationships do
    belongs_to :from_account, App.Ledger.Account do
      attribute_writable? true
    end

    belongs_to :to_account, App.Ledger.Account do
      attribute_writable? true
    end

    has_many :balances, App.Ledger.Balance
  end
end
ZachDaniel
ZachDaniel•8h ago
You need to add require_atomic? false to the update action, if you are going to allow updating the amount of a transfer.
Failz
FailzOP•8h ago
ZachDaniel
ZachDaniel•8h ago
Ah, because its doesn't have backwards compatibility configuration set that changes how default update actions work When I set this: 
config :ash, :default_actions_require_atomic?, true
config :ash, :default_actions_require_atomic?, true
then it fails in the same way before that config was introduced, default actions had an implicit require_atomic? false Its fine to add require_atomic? false, because the relevant accounts are locked before updating them.
Failz
FailzOP•8h ago
you're a step ahead of me, I was trying to think through what gets broken if I set atomic to false. thank you for the help here!
ZachDaniel
ZachDaniel•8h ago
With that said, I'm actually wondering if some recent improvements to this code that we've made lets us loosen the restriction here. oh, no it doesn't I remember why the change logic uses the previous balance to do its work So there actually is something you should do to make this safe for concurrency 
update :update_balance do
  change get_and_lock_for_update()
end
update :update_balance do
  change get_and_lock_for_update()
end
that will ensure that your hook always sees the previous balance properly if you have a chance to add a blurb about this to the docs that would be great. I'm updating the tests to use this new pattern and the new configs so its more realistic.
Failz
FailzOP•8h ago
looks happy!

message.txt

ZachDaniel
ZachDaniel•8h ago
🥳

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