Add new exception to API documentation

[MAILPOET-2107]

doc/api_methods/AddList.md

@@ -17,3 +17,18 @@ An associative array which contains list data.
 | --- | --- | --- | --- |
 | name (required) | string | 90 chars | A name of the list. |
 | description (optional) | string\|null| 250 chars | A description of the list. |
+
+## Error handling
+
+All expected errors from the API are exceptions of class `\MailPoet\API\MP\v1\APIException`. 
+Code of the exception is populated to distinguish between different errors.
+
+An exception of base class `\Exception` can be thrown when something unexpected happens.
+
+Codes description:
+
+| Code | Description |
+| --- | ---  |
+| 14 | Missing list name |
+| 15 | Trying to create a list that already exists |
+| 16 | The list couldn’t be created in the database |

doc/api_methods/AddSubscriber.md

@@ -45,3 +45,19 @@ All options are optional. If omitted a default value is used.
 | send_confirmation_email | boolean | true | Can be used to disable a confirmation email. Otherwise, a confirmation email is sent as described above. It is strongly recommended to keep this option set to `true` so that MailPoet settings for sign-up confirmation are respected. Turning it to `false` might lead that subscriber to be added as `unconfirmed`. |
 | schedule_welcome_email | boolean | true | Can be used to disable a welcome email. Otherwise, a welcome email is scheduled as described above.|
 | skip_subscriber_notification | boolean | false | Can be used to disable an admin notification email. Otherwise, an admin notification email is sent as described above.|
+
+## Error handling
+
+All expected errors from the API are exceptions of class `\MailPoet\API\MP\v1\APIException`. 
+Code of the exception is populated to distinguish between different errors.
+
+An exception of base class `\Exception` can be thrown when something unexpected happens.
+
+Codes description:
+
+| Code | Description |
+| --- | ---  |
+| 11 | Missing email address |
+| 12 | Trying to create a subscriber that already exists |
+| 13 | The subscriber couldn’t be created in the database |
+| 17 | Welcome email failed to send |

doc/api_methods/AddSubscriberField.md

@@ -63,3 +63,25 @@ The common properties for all types:
 | created_at | string\|null | - | UTC time of creation in `Y-m-d H:i:s` format |
 | updated_at | string | - | UTC time of last update in `Y-m-d H:i:s` format |
 
+## Error handling
+
+All expected errors from the API are exceptions of class `\MailPoet\API\MP\v1\APIException`. 
+Code of the exception is populated to distinguish between different errors.
+
+An exception of base class `\Exception` can be thrown when something unexpected happens.
+
+Codes description:
+
+| Code | Description |
+| --- | ---  |
+| 1 | The subscriber couldn’t be created in the database |
+| 1001 | Missing a mandatory field in the `$data` argument |
+| 1002 | A mandatory field in the `$data` argument has wrong type |
+| 1003 | `$params` is not an array |
+| 1004 | Attempting to create a field with an unknown type |
+| 1005 | Incorrect validate parameter for text type |
+| 1006 | Passing a `values` array for the checkbox type that has incorrect number of values |
+| 1007 | Incorrect `date_format` value |
+| 1008 | Incorrect `date_type` value |
+| 1009 | Missing `values` for select or radio types |
+| 1010 | Empty `value` for select or radio types |

doc/api_methods/GetSubscriber.md

@@ -87,3 +87,16 @@ This method throws an `\Exception` in the event a subscriber with a given email
   'cf_2' => 'New York',
 ];
 ```
+
+## Error handling
+
+All expected errors from the API are exceptions of class `\MailPoet\API\MP\v1\APIException`. 
+Code of the exception is populated to distinguish between different errors.
+
+An exception of base class `\Exception` can be thrown when something unexpected happens.
+
+Codes description:
+
+| Code | Description |
+| --- | ---  |
+| 4 | Asking for a subscriber that does not exist. |

doc/api_methods/SubscribeToLists.md

@@ -12,7 +12,6 @@ This method allows adding an existing subscriber into lists and handles confirma
 
 All these emails can be disabled using `$options`.
 
-
 It returns a subscriber. See [Get Subscriber](GetSubscriber.md) for a subscriber data structure.
 
 ## Arguments
@@ -30,3 +29,23 @@ All options are optional. If omitted, a default value is used.
 | send_confirmation_email | boolean | true | Can be used to disable confirmation email. Otherwise, a confirmation email is sent as described above.|
 | schedule_welcome_email | boolean | true | Can be used to disable welcome email. Otherwise, a welcome email is scheduled as described above.|
 | skip_subscriber_notification | boolean | false | Can be used to disable an admin notification email. Otherwise, an admin notification email is sent as described above.|
+
+## Error handling
+
+All expected errors from the API are exceptions of class `\MailPoet\API\MP\v1\APIException`. 
+Code of the exception is populated to distinguish between different errors.
+
+An exception of base class `\Exception` can be thrown when something unexpected happens.
+
+Codes description:
+
+| Code | Description |
+| --- | ---  |
+| 3 | No lists provided |
+| 4 | Invalid subscriber that does not exist |
+| 5 | Invalid list that does not exist |
+| 6 | Trying to subscribe to a WordPress Users list |
+| 7 | Trying to subscribe to a WooCommerce Customers list |
+| 8 | Trying to subscribe to a list that doesn’t support that |
+| 10 | Confirmation email failed to send |
+| 17 | Welcome email failed to send |

doc/api_methods/UnsubscribeFromLists.md

@@ -14,3 +14,21 @@ An id or email of an existing subscriber. An `\Exception` is thrown when an id o
 
 ### array `$list_ids` (required)
 An array of list ids. An `\Exception` is thrown if any of list ids are invalid. In such a case the subscriber remains subscribed to all lists.
+
+## Error handling
+
+All expected errors from the API are exceptions of class `\MailPoet\API\MP\v1\APIException`. 
+Code of the exception is populated to distinguish between different errors.
+
+An exception of base class `\Exception` can be thrown when something unexpected happens.
+
+Codes description:
+
+| Code | Description |
+| --- | ---  |
+| 3 | No lists provided |
+| 4 | Invalid subscriber that does not exist |
+| 5 | Invalid list that does not exist |
+| 6 | Trying to subscribe to a WordPress Users list |
+| 7 | Trying to subscribe to a WooCommerce Customers list |
+| 10 | Confirmation email failed to send |