> ## Documentation Index
> Fetch the complete documentation index at: https://cantonfoundation-dpm-import.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# DA.Exception

> Reference documentation for Daml module DA.Exception.

<span id="module-da-exception-55791" />

# DA.Exception

Exception handling in Daml.

DEPRECATED: Use `failWithStatus` and `FailureStatus` over Daml Exceptions

## Module Snapshot

<CardGroup cols={2}>
  <Card title="Lifecycle">
    Deprecated.
  </Card>

  <Card title="Notices">
    Status: `active`
    Introduced in: `3.4.9`
    Removed in: `-`
    Warnings: `0`
    Deprecations: `2`
    Deprecated since: `3.4.9`
  </Card>
</CardGroup>

<Warning>
  Exceptions are deprecated, prefer `failWithStatus`, and avoid using catch.
</Warning>

<AccordionGroup>
  <Accordion title="All deprecations (2)">
    * Exceptions are deprecated, prefer `failWithStatus`, and avoid using catch.
    * Use `-Wno-deprecated-exceptions` to disable this warning.
  </Accordion>
</AccordionGroup>

## Data Types

<span id="type-da-internal-exception-exception-4133" />

### `type Exception e`

\= ([`HasThrow`](#class-da-internal-exception-hasthrow-30284) `e`, [`HasMessage`](#class-da-internal-exception-hasmessage-3179) `e`, [`HasToAnyException`](#class-da-internal-exception-hastoanyexception-55973) `e`, [`HasFromAnyException`](#class-da-internal-exception-hasfromanyexception-16788) `e`)

Exception typeclass. This should not be implemented directly,
instead, use the `exception` syntax.

<span id="type-da-exception-arithmeticerror-arithmeticerror-68828" />

### `data ArithmeticError`

Exception raised by an arithmetic operation, such as divide-by-zero or overflow.

<Warning>
  Deprecated: Exceptions are deprecated, prefer `failWithStatus`, and avoid using catch.
</Warning>

<Warning>
  Deprecated: Use `-Wno-deprecated-exceptions` to disable this warning.
</Warning>

Constructors:

<span id="constr-da-exception-arithmeticerror-arithmeticerror-83141" />

* `ArithmeticError`

<ResponseField name="message" type="Text" />

<span id="type-da-exception-assertionfailed-assertionfailed-69740" />

### `data AssertionFailed`

Exception raised by assert functions in DA.Assert

<Warning>
  Deprecated: Exceptions are deprecated, prefer `failWithStatus`, and avoid using catch.
</Warning>

<Warning>
  Deprecated: Use `-Wno-deprecated-exceptions` to disable this warning.
</Warning>

Constructors:

<span id="constr-da-exception-assertionfailed-assertionfailed-2357" />

* `AssertionFailed`

<ResponseField name="message" type="Text" />

<span id="type-da-exception-generalerror-generalerror-5800" />

### `data GeneralError`

Exception raised by `error`.

<Warning>
  Deprecated: Exceptions are deprecated, prefer `failWithStatus`, and avoid using catch.
</Warning>

<Warning>
  Deprecated: Use `-Wno-deprecated-exceptions` to disable this warning.
</Warning>

Constructors:

<span id="constr-da-exception-generalerror-generalerror-9293" />

* `GeneralError`

<ResponseField name="message" type="Text" />

<span id="type-da-exception-preconditionfailed-preconditionfailed-61218" />

### `data PreconditionFailed`

Exception raised when a contract is invalid, i.e. fails the ensure clause.

<Warning>
  Deprecated: Exceptions are deprecated, prefer `failWithStatus`, and avoid using catch.
</Warning>

<Warning>
  Deprecated: Use `-Wno-deprecated-exceptions` to disable this warning.
</Warning>

Constructors:

<span id="constr-da-exception-preconditionfailed-preconditionfailed-18759" />

* `PreconditionFailed`

<ResponseField name="message" type="Text" />

## Typeclasses

<span id="class-da-internal-exception-hasthrow-30284" />

### `class HasThrow e`

Part of the `Exception` constraint.

Methods:

* `throwPure` : `e` -> `t`
  Throw exception in a pure context.

Instances:

* instance [`HasThrow`](#class-da-internal-exception-hasthrow-30284) [`ArithmeticError`](#type-da-exception-arithmeticerror-arithmeticerror-68828)
* instance [`HasThrow`](#class-da-internal-exception-hasthrow-30284) [`AssertionFailed`](#type-da-exception-assertionfailed-assertionfailed-69740)
* instance [`HasThrow`](#class-da-internal-exception-hasthrow-30284) [`GeneralError`](#type-da-exception-generalerror-generalerror-5800)
* instance [`HasThrow`](#class-da-internal-exception-hasthrow-30284) [`PreconditionFailed`](#type-da-exception-preconditionfailed-preconditionfailed-61218)

<span id="class-da-internal-exception-hasmessage-3179" />

### `class HasMessage e`

Part of the `Exception` constraint.

Methods:

* `message` : `e` -> [`Text`](/appdev/reference/daml-standard-library/prelude#type-ghc-types-text-51952)
  Get the error message associated with an exception.

Instances:

* instance [`HasMessage`](#class-da-internal-exception-hasmessage-3179) [`AnyException`](/appdev/reference/daml-standard-library/prelude#type-da-internal-lf-anyexception-7004)
* instance [`HasMessage`](#class-da-internal-exception-hasmessage-3179) [`ArithmeticError`](#type-da-exception-arithmeticerror-arithmeticerror-68828)
* instance [`HasMessage`](#class-da-internal-exception-hasmessage-3179) [`AssertionFailed`](#type-da-exception-assertionfailed-assertionfailed-69740)
* instance [`HasMessage`](#class-da-internal-exception-hasmessage-3179) [`GeneralError`](#type-da-exception-generalerror-generalerror-5800)
* instance [`HasMessage`](#class-da-internal-exception-hasmessage-3179) [`PreconditionFailed`](#type-da-exception-preconditionfailed-preconditionfailed-61218)

<span id="class-da-internal-exception-hastoanyexception-55973" />

### `class HasToAnyException e`

Part of the `Exception` constraint.

Methods:

* `toAnyException` : `e` -> [`AnyException`](/appdev/reference/daml-standard-library/prelude#type-da-internal-lf-anyexception-7004)
  Convert an exception type to AnyException.

Instances:

* instance [`HasToAnyException`](#class-da-internal-exception-hastoanyexception-55973) [`AnyException`](/appdev/reference/daml-standard-library/prelude#type-da-internal-lf-anyexception-7004)
* instance [`HasToAnyException`](#class-da-internal-exception-hastoanyexception-55973) [`ArithmeticError`](#type-da-exception-arithmeticerror-arithmeticerror-68828)
* instance [`HasToAnyException`](#class-da-internal-exception-hastoanyexception-55973) [`AssertionFailed`](#type-da-exception-assertionfailed-assertionfailed-69740)
* instance [`HasToAnyException`](#class-da-internal-exception-hastoanyexception-55973) [`GeneralError`](#type-da-exception-generalerror-generalerror-5800)
* instance [`HasToAnyException`](#class-da-internal-exception-hastoanyexception-55973) [`PreconditionFailed`](#type-da-exception-preconditionfailed-preconditionfailed-61218)

<span id="class-da-internal-exception-hasfromanyexception-16788" />

### `class HasFromAnyException e`

Part of the `Exception` constraint.

Methods:

* `fromAnyException` : [`AnyException`](/appdev/reference/daml-standard-library/prelude#type-da-internal-lf-anyexception-7004) -> [`Optional`](/appdev/reference/daml-standard-library/prelude#type-da-internal-prelude-optional-37153) `e`
  Convert an AnyException back to the underlying exception type, if possible.

Instances:

* instance [`HasFromAnyException`](#class-da-internal-exception-hasfromanyexception-16788) [`AnyException`](/appdev/reference/daml-standard-library/prelude#type-da-internal-lf-anyexception-7004)
* instance [`HasFromAnyException`](#class-da-internal-exception-hasfromanyexception-16788) [`ArithmeticError`](#type-da-exception-arithmeticerror-arithmeticerror-68828)
* instance [`HasFromAnyException`](#class-da-internal-exception-hasfromanyexception-16788) [`AssertionFailed`](#type-da-exception-assertionfailed-assertionfailed-69740)
* instance [`HasFromAnyException`](#class-da-internal-exception-hasfromanyexception-16788) [`GeneralError`](#type-da-exception-generalerror-generalerror-5800)
* instance [`HasFromAnyException`](#class-da-internal-exception-hasfromanyexception-16788) [`PreconditionFailed`](#type-da-exception-preconditionfailed-preconditionfailed-61218)

<span id="class-da-internal-exception-actionthrow-37623" />

### `class Action m => ActionThrow m`

Action type in which `throw` is supported.

Methods:

* `throw` : [`Exception`](#type-da-internal-exception-exception-4133) `e` => `e` -> `m` `t`

Instances:

* instance [`ActionThrow`](#class-da-internal-exception-actionthrow-37623) [`Update`](/appdev/reference/daml-standard-library/prelude#type-da-internal-lf-update-68072)

<span id="class-da-internal-exception-actioncatch-69238" />

### `class ActionThrow m => ActionCatch m`

Action type in which `try ... catch ...` is supported.
DEPRECATED: Avoid the use of catch in daml code, prefer error handling on client, and throwing using `failWithStatus`

Methods:

* `_tryCatch` : (() -> `m` `t`) -> ([`AnyException`](/appdev/reference/daml-standard-library/prelude#type-da-internal-lf-anyexception-7004) -> [`Optional`](/appdev/reference/daml-standard-library/prelude#type-da-internal-prelude-optional-37153) (`m` `t`)) -> `m` `t`
  Handle an exception. Use the `try ... catch ...` syntax
  instead of calling this method directly.

Instances:

* instance [`ActionCatch`](#class-da-internal-exception-actioncatch-69238) [`Update`](/appdev/reference/daml-standard-library/prelude#type-da-internal-lf-update-68072)

## Orphan Typeclass Instances

* instance [`GetField`](/appdev/reference/daml-standard-library/da-record#class-da-internal-record-getfield-53979) `message` [`GeneralError`](#type-da-exception-generalerror-generalerror-5800) [`Text`](/appdev/reference/daml-standard-library/prelude#type-ghc-types-text-51952)

* instance [`SetField`](/appdev/reference/daml-standard-library/da-record#class-da-internal-record-setfield-4311) `message` [`GeneralError`](#type-da-exception-generalerror-generalerror-5800) [`Text`](/appdev/reference/daml-standard-library/prelude#type-ghc-types-text-51952)

* instance [`GetField`](/appdev/reference/daml-standard-library/da-record#class-da-internal-record-getfield-53979) `message` [`ArithmeticError`](#type-da-exception-arithmeticerror-arithmeticerror-68828) [`Text`](/appdev/reference/daml-standard-library/prelude#type-ghc-types-text-51952)

* instance [`SetField`](/appdev/reference/daml-standard-library/da-record#class-da-internal-record-setfield-4311) `message` [`ArithmeticError`](#type-da-exception-arithmeticerror-arithmeticerror-68828) [`Text`](/appdev/reference/daml-standard-library/prelude#type-ghc-types-text-51952)

* instance [`GetField`](/appdev/reference/daml-standard-library/da-record#class-da-internal-record-getfield-53979) `message` [`PreconditionFailed`](#type-da-exception-preconditionfailed-preconditionfailed-61218) [`Text`](/appdev/reference/daml-standard-library/prelude#type-ghc-types-text-51952)

* instance [`SetField`](/appdev/reference/daml-standard-library/da-record#class-da-internal-record-setfield-4311) `message` [`PreconditionFailed`](#type-da-exception-preconditionfailed-preconditionfailed-61218) [`Text`](/appdev/reference/daml-standard-library/prelude#type-ghc-types-text-51952)

* instance [`GetField`](/appdev/reference/daml-standard-library/da-record#class-da-internal-record-getfield-53979) `message` [`AssertionFailed`](#type-da-exception-assertionfailed-assertionfailed-69740) [`Text`](/appdev/reference/daml-standard-library/prelude#type-ghc-types-text-51952)

* instance [`SetField`](/appdev/reference/daml-standard-library/da-record#class-da-internal-record-setfield-4311) `message` [`AssertionFailed`](#type-da-exception-assertionfailed-assertionfailed-69740) [`Text`](/appdev/reference/daml-standard-library/prelude#type-ghc-types-text-51952)