系统检查框架

系统检查框架是一组验证Django项目的静态检查。 它检测到常见的问题，并提供了如何解决这些问题的提示。 该框架是可扩展的，所以你可以轻松地添加自己的检查。

有关如何添加自己的检查并将其与 Django 的系统检查集成的详细信息，请参阅：doc：系统检查主题指南</topics/checks>。

API 参考

“CheckMessage”

• class CheckMessage(level, msg, hint=None, obj=None, id=None)[源代码]
• 系统检查提出的警告和错误必须是“CheckMessage”的实例。 一个实例封装了一个可报告的错误或警告。 它还提供适用于消息的上下文和提示以及用于过滤目的的唯一标识符。

构造方法的参数：

• level
• 消息的严重性。 使用其中一个预定义的值：DEBUG，INFO，WARNING，ERROR，CRITICAL。 如果级别大于或等于“ERROR”，则Django将阻止执行管理命令。 级别低于“ERROR”的消息（即警告）被报告给控制台，但是可以被静默。
• msg
• 用来描述问题的一个简短字符串(少于80个字符)。这个字符串不应该包含换行符。
• hint
• 提供解决问题的提示的单行字符串。 如果不能提供提示，或者错误消息中的提示是显而易见的，则提示可以省略，或者可以使用“None”的值。
• obj
• Optional. An object providing context for the message (for example, themodel where the problem was discovered). The object should be a model,field, or manager or any other object that defines a str() method.The method is used while reporting all messages and its result precedes themessage.
• id

• Optional string. A unique identifier for the issue. Identifiers shouldfollow the pattern applabel.X001, where X is one of the lettersCEWID, indicating the message severity (C for criticals, E forerrors and so). The number can be allocated by the application, but shouldbe unique within that application.有一些子类可以使创建通用级别的消息更简单。 当使用它们时，可以省略“level”参数，因为它是由类名所隐含的。

• class Debug(msg, hint=None, obj=None, id=None)[源代码]

• class Info(msg, hint=None, obj=None, id=None)[源代码]
• class Warning(msg, hint=None obj=None, id=None)[源代码]
• class Error(msg, hint=None, obj=None, id=None)[源代码]
• class Critical(msg, hint=None, obj=None, id=None)[源代码]

内置标签

Django 的系统检查按以下标签组织：

• admin：检查所有后台站点申明。
• caches：检查缓存相关的配置。
• compatibility：标记版本升级可能导致的问题。
• database: Checks database-related configuration issues. Database checksare not run by default because they do more than static code analysis asregular checks do. They are only run by the migrate command or ifyou specify the database tag when calling the check command.
• models：检查模型，字段和管理器定义。
• security：检查安全相关配置。
• signals：检查信号申明和处理器注册信息。
• staticfiles：检查 django.contrib.staticfiles 配置。
• templates：检查模板相关配置。
• translation：检查翻译相关配置。
• urls：检查 URL 配置。一些可能通过多个标签同时注册的检查项。

核心系统检查

向后兼容

兼容性检查警告那些升级 Django 后可能出现的问题。

• 2_0.W001: Your URL pattern <pattern> has a route that contains(?P<, begins with a ^, or ends with a $. This was likely anoversight when migrating from url() to path().

缓存

The following checks verify that your CACHES setting is correctlyconfigured:

• caches.E001: You must define a 'default' cache in yourCACHES setting.

数据库

MySQL

如果您使用MySQL，需要执行以下检查：

• mysql.E001: MySQL does not allow unique CharFields to have amax_length > 255.
• mysql.W002: MySQL Strict Mode is not set for database connection''. See also Setting sql_mode.

模型字段

• fields.E001: 字段名不能已下划线结尾。
• fields.E002: 字段名不能有 "__".
• fields.E003*: pk 是保留关键字，不能作为字段名使用。
• fields.E004 []($f7bf743d573b0138.md#id1)：“choices”必须是可迭代的（例如，列表或元组）。
• fields.E005 []($f7bf743d573b0138.md#id1)：``choices必须是一个可返回的（实际值，易读的名称）``构成元组。
• fields.E006 []($f7bf743d573b0138.md#id1)：db_index必须是`None`，True`或False。
• fields.E007 []($f7bf743d573b0138.md#id1)：主键不能有“null = True”。
• fields.E008：所有 validators 必须都是可调用的。
• fields.E100： AutoField` 必须设置 primary_key=True。
• fields.E110: BooleanFields do not accept null values. This checkappeared before support for null values was added in Django 2.1.
• fields.E120： CharField 必须定义一个 max_length 属性。
• fields.E121： max_length 必须是个正整数。
• fields.W122： max_length 在使用 <integer field type> 时会被忽略。
• fields.E130： DecimalField 必须定义一个 decimal_places 属性。
• fields.E131： decimal_places 必须是个非负整数。
• fields.E132： DecimalField 必须定义一个 max_digits 属性。
• fields.E133： max_digits 必须是一个非负整数。
• fields.E134： max_digits 必须大于或等于 decimal_places。
• fields.E140： FilePathField 的 allow_files 或 allow_folders 必须有一个被设为 True。
• fields.E150： 若GenericIPAddressField 不允许 null 值，那么它也不接受空值，因为空值被保存为 null。
• fields.E160: The options auto_now, auto_now_add, and defaultare mutually exclusive. Only one of these options may be present.
• fields.W161：默认绑定值。
• fields.W162： <database> 并不支持在 <field data type> 列上创建数据库索引。
• fields.E900: IPAddressField has been removed except for support inhistorical migrations.
• fields.W900: IPAddressField has been deprecated. Support for it(except in historical migrations) will be removed in Django 1.9. This checkappeared in Django 1.7 and 1.8.
• fields.W901: CommaSeparatedIntegerField has been deprecated. Supportfor it (except in historical migrations) will be removed in Django 2.0. Thischeck appeared in Django 1.10 and 1.11.
• fields.E901: CommaSeparatedIntegerField is removed except for supportin historical migrations.
• fields.W902: FloatRangeField is deprecated and will be removed inDjango 3.1.

文件字段

• fields.E200: unique is not a valid argument for a FileField.This check is removed in Django 1.11.
• fields.E201： primary_key 对于 FileField 来说不是个有效的参数。
• fields.E202： FileField 的 upload_to 参数必须是个相对路径，而不是一个相对路径。
• fields.E210： 不能使用 ImageField，因为未安装 Pillow。

关联字段

• fields.E300: Field defines a relation with model <model>, which iseither not installed, or is abstract.
• fields.E301: Field defines a relation with the model <model> whichhas been swapped out.
• fields.E302: Accessor for field <field name> clashes with field<field name>.
• fields.E303: Reverse query name for field <field name> clashes withfield <field name>.
• fields.E304: Field name <field name> clashes with accessor for<field name>.
• fields.E305: Field name <field name> clashes with reverse query namefor <field name>.
• fields.E306: Related name must be a valid Python identifier or end witha '+'.
• fields.E307: The field <app label>.<model>.<field name> was declaredwith a lazy reference to <app label>.<model>, but app <app label>isn't installed or doesn't provide model <model>.
• fields.E308: Reverse query name <related query name> must not endwith an underscore.
• fields.E309: Reverse query name <related query name> must not contain'__'.
• fields.E310: No subset of the fields <field1>, <field2>, … onmodel <model> is unique. Add unique=True on any of those fields oradd at least a subset of them to a unique_together constraint.
• fields.E311: <model> must set unique=True because it isreferenced by a ForeignKey.
• fields.E312: The to_field <field name> doesn't exist on therelated model <app label>.<model>.
• fields.E320: Field specifies on_delete=SET_NULL, but cannot be null.
• fields.E321: The field specifies on_delete=SET_DEFAULT, but has nodefault value.
• fields.E330: ManyToManyFields cannot be unique.
• fields.E331: Field specifies a many-to-many relation through model<model>, which has not been installed.
• fields.E332: Many-to-many fields with intermediate tables must not besymmetrical.
• fields.E333: The model is used as an intermediate model by <model>,but it has more than two foreign keys to <model>, which is ambiguous.You must specify which two foreign keys Django should use via thethrough_fields keyword argument.
• fields.E334: The model is used as an intermediate model by <model>,but it has more than one foreign key from <model>, which is ambiguous.You must specify which foreign key Django should use via thethrough_fields keyword argument.
• fields.E335: The model is used as an intermediate model by <model>,but it has more than one foreign key to <model>, which is ambiguous.You must specify which foreign key Django should use via thethrough_fields keyword argument.
• fields.E336: The model is used as an intermediary model by <model>,but it does not have foreign key to <model> or <model>.
• fields.E337: Field specifies through_fields but does not provide thenames of the two link fields that should be used for the relation through<model>.
• fields.E338: The intermediary model <through model> has no field<field name>.
• fields.E339: <model>.<field name> is not a foreign key to <model>.
• fields.E340: The field's intermediary table <table name> clashes withthe table name of <model>/<model>.<field name>.
• fields.W340: null has no effect on ManyToManyField.
• fields.W341: ManyToManyField does not support validators.
• fields.W342: Setting unique=True on a ForeignKey has the sameeffect as using a OneToOneField.
• fields.W343: limit_choices_to has no effect on ManyToManyFieldwith a through model.

模型

• models.E001： <swappable> 不是表单 app_label.app_name。
• models.E002: <SETTING> references <model>, which has not beeninstalled, or is abstract.
• models.E003: The model has two identical many-to-many relations throughthe intermediate model <app_label>.<model>.
• models.E004: id can only be used as a field name if the field alsosets primary_key=True.
• models.E005: The field <field name> from parent model <model>clashes with the field <field name> from parent model <model>.
• models.E006：与另一个模型 <model> 的字段 <field name> 冲突的字段。
• models.E007： 列名 <column name> 被其它字段使用的字段 <field name> 。
• models.E008： index_together 必须是个列表或元组。
• models.E009： 所有 index_together 元素都必须是列表或元组。
• models.E010： unique_together 必须是个列表或元组。
• models.E011： 所有 unique_together 元素都必须是列表或元组。
• models.E012： indexes/index_together/unique_together 指向了不存在的字段 <field name>。
• models.E013： indexes/index_together/unique_together 指向一个 ManyToManyField <field name>，但此选项不支持 ManyToManyField。
• models.E014： ordering 必须是个元组或列表（即便你只想按照一个字段进行排序）。
• models.E015： ordering 指向了不存在的字段 <field name>。
• models.E016: indexes/index_together/unique_together refers to field<field_name> which is not local to model <model>.
• models.E017: Proxy model <model> contains model fields.
• models.E018: Autogenerated column name too long for field <field>.Maximum length is <maximum length> for database <alias>.
• models.E019: Autogenerated column name too long for M2M field<M2M field>. Maximum length is <maximum length> for database<alias>.
• models.E020: The <model>.check() class method is currently overridden.
• models.E021: ordering and order_with_respect_to cannot be usedtogether.
• models.E022: <function> contains a lazy reference to<app label>.<model>, but app <app label> isn't installed ordoesn't provide model <model>.
• models.E023: The model name <model> cannot start or end with anunderscore as it collides with the query lookup syntax.
• models.E024: The model name <model> cannot contain double underscoresas it collides with the query lookup syntax.
• models.E025: The property <property name> clashes with a relatedfield accessor.
• models.E026: The model cannot have more than one field withprimary_key=True.
• models.W027: <database> does not support check constraints.
• models.E028: db_table <db_table> is used by multiple models:<model list>.
• models.W035: db_table <db_table> is used by multiple models:<model list>.

安全

The security checks do not make your site secure. They do not audit code, dointrusion detection, or do anything particularly complex. Rather, they helpperform an automated, low-hanging-fruit checklist. They help you remember thesimple things that improve your site's security.

Some of these checks may not be appropriate for your particular deploymentconfiguration. For instance, if you do your HTTP to HTTPS redirection in a loadbalancer, it'd be irritating to be constantly warned about not having enabledSECURE_SSL_REDIRECT. Use SILENCED_SYSTEM_CHECKS tosilence unneeded checks.

The following checks are run if you use the check —deploy option:

• security.W001: You do not havedjango.middleware.security.SecurityMiddleware in yourMIDDLEWARE so the SECURE_HSTS_SECONDS,SECURE_CONTENT_TYPE_NOSNIFF, SECURE_BROWSER_XSS_FILTER,and SECURE_SSL_REDIRECT settings will have no effect.
• security.W002: You do not havedjango.middleware.clickjacking.XFrameOptionsMiddleware in yourMIDDLEWARE, so your pages will not be served with an'x-frame-options' header. Unless there is a good reason for yoursite to be served in a frame, you should consider enabling thisheader to help prevent clickjacking attacks.
• security.W003: You don't appear to be using Django's built-in cross-siterequest forgery protection via the middleware(django.middleware.csrf.CsrfViewMiddleware is not in yourMIDDLEWARE). Enabling the middleware is the safestapproach to ensure you don't leave any holes.
• security.W004: You have not set a value for theSECURE_HSTS_SECONDS setting. If your entire site is served onlyover SSL, you may want to consider setting a value and enabling HTTPStrict Transport Security. Be sure to readthe documentation first; enabling HSTS carelessly can cause serious,irreversible problems.
• security.W005: You have not set theSECURE_HSTS_INCLUDE_SUBDOMAINS setting to True. Without this,your site is potentially vulnerable to attack via an insecure connection to asubdomain. Only set this to True if you are certain that all subdomains ofyour domain should be served exclusively via SSL.
• security.W006: Your SECURE_CONTENT_TYPE_NOSNIFF setting is notset to True, so your pages will not be served with an'X-Content-Type-Options: nosniff' header. You should consider enablingthis header to prevent the browser from identifying content types incorrectly.
• security.W007: Your SECURE_BROWSER_XSS_FILTER setting is notset to True, so your pages will not be served with an'X-XSS-Protection: 1; mode=block' header. You should consider enablingthis header to activate the browser's XSS filtering and help prevent XSSattacks.
• security.W008: Your SECURE_SSL_REDIRECT setting is not set toTrue. Unless your site should be available over both SSL and non-SSLconnections, you may want to either set this setting to True or configurea load balancer or reverse-proxy server to redirect all connections to HTTPS.
• security.W009: Your SECRET_KEY has less than 50 characters orless than 5 unique characters. Please generate a long and randomSECRET_KEY, otherwise many of Django's security-critical features will bevulnerable to attack.
• security.W010: You have django.contrib.sessions in yourINSTALLED_APPS but you have not setSESSION_COOKIE_SECURE to True. Using a secure-only sessioncookie makes it more difficult for network traffic sniffers to hijack usersessions.
• security.W011: You havedjango.contrib.sessions.middleware.SessionMiddleware in yourMIDDLEWARE, but you have not set SESSION_COOKIE_SECUREto True. Using a secure-only session cookie makes it more difficult fornetwork traffic sniffers to hijack user sessions.
• security.W012: SESSION_COOKIE_SECURE is not set to True.Using a secure-only session cookie makes it more difficult for network trafficsniffers to hijack user sessions.
• security.W013: You have django.contrib.sessions in yourINSTALLED_APPS, but you have not setSESSION_COOKIE_HTTPONLY to True. Using an HttpOnly sessioncookie makes it more difficult for cross-site scripting attacks to hijack usersessions.
• security.W014: You havedjango.contrib.sessions.middleware.SessionMiddleware in yourMIDDLEWARE, but you have not set SESSION_COOKIE_HTTPONLYto True. Using an HttpOnly session cookie makes it more difficult forcross-site scripting attacks to hijack user sessions.
• security.W015: SESSION_COOKIE_HTTPONLY is not set to True.Using an HttpOnly session cookie makes it more difficult for cross-sitescripting attacks to hijack user sessions.
• security.W016: CSRF_COOKIE_SECURE is not set to True.Using a secure-only CSRF cookie makes it more difficult for network trafficsniffers to steal the CSRF token.
• security.W017: CSRF_COOKIE_HTTPONLY is not set to True.Using an HttpOnly CSRF cookie makes it more difficult for cross-sitescripting attacks to steal the CSRF token. This check is removed in Django1.11 as theCSRF_COOKIE_HTTPONLYsetting offers no praticalbenefit.
• security.W018: You should not have DEBUG set to True indeployment.
• security.W019: You havedjango.middleware.clickjacking.XFrameOptionsMiddleware in yourMIDDLEWARE, but X_FRAME_OPTIONS is not set to'DENY'. The default is 'SAMEORIGIN', but unless there is a good reasonfor your site to serve other parts of itself in a frame, you should changeit to 'DENY'.
• security.W020: ALLOWED_HOSTS must not be empty in deployment.
• security.W021: You have not set theSECURE_HSTS_PRELOAD setting to True. Without this, your sitecannot be submitted to the browser preload list.

信号

• signals.E001: <handler> was connected to the <signal> signal witha lazy reference to the sender <app label>.<model>, but app <app label>isn't installed or doesn't provide model <model>.

模板

The following checks verify that your TEMPLATES setting is correctlyconfigured:

• templates.E001: You have 'APP_DIRS': True in yourTEMPLATES but also specify 'loaders' in OPTIONS. Eitherremove APP_DIRS or remove the 'loaders' option.
• templates.E002: string_if_invalid in TEMPLATESOPTIONS must be a string but got: {value}({type}).

翻译

The following checks are performed on your translation configuration:

• translation.E001: You have provided an invalid value for theLANGUAGE_CODE setting.

URLs

以下检查项针对你的 URL 配置执行：

• urls.W001: Your URL pattern <pattern> usesinclude() with a route ending with a $. Remove thedollar from the route to avoid problems including URLs.
• urls.W002: Your URL pattern <pattern> has a route beginning witha /. Remove this slash as it is unnecessary. If this pattern is targetedin an include(), ensure the include()pattern has a trailing /.
• urls.W003: Your URL pattern <pattern> has a nameincluding a :. Remove the colon, to avoid ambiguous namespacereferences.
• urls.E004: Your URL pattern <pattern> is invalid. Ensure thaturlpatterns is a list of path() and/orre_path() instances.
• urls.W005: URL namespace <namespace> isn't unique. You may not beable to reverse all URLs in this namespace.
• urls.E006: The MEDIA_URL/ STATIC_URL setting mustend with a slash.
• urls.E007: The custom handlerXXX view 'path.to.view' does nottake the correct number of arguments (…).
• urls.E008: The custom handlerXXX view 'path.to.view' could not beimported.

contrib 应用检查

admin

后台检查项均作为 admin 标签的一部分执行。

以下检查项在每个通过后台站点注册的 ModelAdmin （或其子类）上执行。

• admin.E001： raw_id_fields 的值必须是个列表或元组。
• admin.E002： raw_id_fields[n] 的值指向 <field name>，它并不是 <model> 的属性。
• admin.E003： raw_id_fields[n] 的值必须是个外键或一个多对多字段。
• admin.E004： fields 的值必须是列表或元组。
• admin.E005： fieldsets 和 fields 都是定制的。
• admin.E006： fields 的值包含了重复字段。
• admin.E007： fieldsets 的值必须是个列表或元组。
• admin.E008： fieldsets[n] 的值必须是个列表或元组。
• admin.E009： fieldsets[n] 的值的长度必须是 2。
• admin.E010： fieldsets[n][1] 的值必须是个字典。
• admin.E011： fieldsets[n][1] 的值必须包含键 fields。
• admin.E012： fieldsets[n][1] 中有重复字段。
• admin.E013: fields[n]/fieldsets[n][m] cannot include theManyToManyField <field name>, because that field manually specifies arelationship model.
• admin.E014： exclude 的值必须是个列表或元组。
• admin.E015： exclude 的值必须包含重复字段。
• admin.E016： form 的值必须继承自 BaseModelForm。
• admin.E017： filter_vertical 的值必须是个列表或元组。
• admin.E018： filter_horizontal 的值必须是个列表或元组。
• admin.E019: The value of filter_vertical[n]/filter_vertical[n] refersto <field name>, which is not an attribute of <model>.
• admin.E020: The value of filter_vertical[n]/filter_vertical[n] mustbe a many-to-many field.
• admin.E021: The value of radio_fields must be a dictionary.
• admin.E022: The value of radio_fields refers to <field name>,which is not an attribute of <model>.
• admin.E023: The value of radio_fields refers to <field name>,which is not a ForeignKey, and does not have a choices definition.
• admin.E024: The value of radio_fields[<field name>] must be eitheradmin.HORIZONTAL or admin.VERTICAL.
• admin.E025: The value of view_on_site must be either a callable or aboolean value.
• admin.E026: The value of prepopulated_fields must be a dictionary.
• admin.E027: The value of prepopulated_fields refers to<field name>, which is not an attribute of <model>.
• admin.E028: The value of prepopulated_fields refers to<field name>, which must not be a DateTimeField, a ForeignKey,a OneToOneField, or a ManyToManyField field.
• admin.E029: The value of prepopulated_fields[<field name>] must be alist or tuple.
• admin.E030: The value of prepopulated_fields refers to<field name>, which is not an attribute of <model>.
• admin.E031: The value of ordering must be a list or tuple.
• admin.E032: The value of ordering has the random ordering marker?, but contains other fields as well.
• admin.E033: The value of ordering refers to <field name>, whichis not an attribute of <model>.
• admin.E034: The value of readonly_fields must be a list or tuple.
• admin.E035: The value of readonly_fields[n] is not a callable, anattribute of <ModelAdmin class>, or an attribute of <model>.
• admin.E036: The value of autocomplete_fields must be a list or tuple.
• admin.E037: The value of autocomplete_fields[n] refers to<field name>, which is not an attribute of <model>.
• admin.E038: The value of autocomplete_fields[n] must be a foreignkey or a many-to-many field.
• admin.E039: An admin for model <model> has to be registered to bereferenced by <modeladmin>.autocomplete_fields.
• admin.E040: <modeladmin> must define search_fields, becauseit's referenced by <other_modeladmin>.autocomplete_fields.

ModelAdmin

The following checks are performed on anyModelAdmin that is registeredwith the admin site:

• admin.E101： save_as 的值必须是个布尔值。
• admin.E102： save_on_top 的值必须是个布尔值。
• admin.E103： inlines 的值必须是个列表或元组。
• admin.E104： <InlineModelAdmin class> 必须继承自 InlineModelAdmin。
• admin.E105： <InlineModelAdmin class> 必须有个 model 属性。
• admin.E106： <InlineModelAdmin class>.model 的值必须是个 Model。
• admin.E107： list_display 的值必须是个列表或元组。
• admin.E108: The value of list_display[n] refers to <label>,which is not a callable, an attribute of <ModelAdmin class>, or anattribute or method on <model>.
• admin.E109： list_display[n] 的值绝对不能是个 ManyToManyField 字段。
• admin.E110: The value of list_display_links must be a list, a tuple,or None.
• admin.E111: The value of list_display_links[n] refers to <label>,which is not defined in list_display.
• admin.E112: The value of list_filter must be a list or tuple.
• admin.E113: The value of list_filter[n] must inherit fromListFilter.
• admin.E114: The value of list_filter[n] must not inherit fromFieldListFilter.
• admin.E115: The value of list_filter[n][1] must inherit fromFieldListFilter.
• admin.E116: The value of list_filter[n] refers to <label>,which does not refer to a Field.
• admin.E117: The value of list_select_related must be a boolean,tuple or list.
• admin.E118: The value of list_per_page must be an integer.
• admin.E119: The value of list_max_show_all must be an integer.
• admin.E120: The value of list_editable must be a list or tuple.
• admin.E121: The value of list_editable[n] refers to <label>,which is not an attribute of <model>.
• admin.E122: The value of list_editable[n] refers to <label>,which is not contained in list_display.
• admin.E123: The value of list_editable[n] cannot be in bothlist_editable and list_display_links.
• admin.E124: The value of list_editable[n] refers to the first fieldin list_display (<label>), which cannot be used unlesslist_display_links is set.
• admin.E125: The value of list_editable[n] refers to <field name>,which is not editable through the admin.
• admin.E126: The value of search_fields must be a list or tuple.
• admin.E127: The value of date_hierarchy refers to <field name>,which does not refer to a Field.
• admin.E128: The value of date_hierarchy must be a DateField orDateTimeField.
• admin.E129: <modeladmin> must define a has_<foo>_permission()method for the <action> action.
• admin.E130: name attributes of actions defined in<modeladmin> must be unique.

InlineModelAdmin

The following checks are performed on anyInlineModelAdmin that is registered as aninline on a ModelAdmin.

• admin.E201: Cannot exclude the field <field name>, because it is theforeign key to the parent model <app_label>.<model>.
• admin.E202: <model> has no ForeignKey to <parent model>./<model> has more than one ForeignKey to <parent model>.
• admin.E203: The value of extra must be an integer.
• admin.E204: The value of max_num must be an integer.
• admin.E205: The value of min_num must be an integer.
• admin.E206: The value of formset must inherit fromBaseModelFormSet.

GenericInlineModelAdmin

The following checks are performed on anyGenericInlineModelAdmin that isregistered as an inline on a ModelAdmin.

• admin.E301: 'ct_field' references <label>, which is not a fieldon <model>.
• admin.E302: 'ct_fk_field' references <label>, which is not afield on <model>.
• admin.E303: <model> has no GenericForeignKey.
• admin.E304: <model> has no GenericForeignKey using content typefield <field name> and object ID field <field name>.

AdminSite

The following checks are performed on the defaultAdminSite:

• admin.E401: django.contrib.contenttypes must be inINSTALLED_APPS in order to use the admin application.
• admin.E402: django.contrib.auth.context_processors.authmust be enabled in DjangoTemplates(TEMPLATES) if using the default auth backend in order to use theadmin application.
• admin.E403: A django.template.backends.django.DjangoTemplatesinstance must be configured in TEMPLATES in order to use theadmin application.
• admin.E404: django.contrib.messages.context_processors.messagesmust be enabled in DjangoTemplates(TEMPLATES) in order to use the admin application.
• admin.E405: django.contrib.auth must be inINSTALLED_APPS in order to use the admin application.
• admin.E406: django.contrib.messages must be inINSTALLED_APPS in order to use the admin application.
• admin.E408:django.contrib.auth.middleware.AuthenticationMiddleware must be inMIDDLEWARE in order to use the admin application.
• admin.E409: django.contrib.messages.middleware.MessageMiddlewaremust be in MIDDLEWARE in order to use the admin application.
• admin.E410: django.contrib.sessions.middleware.SessionMiddlewaremust be in MIDDLEWARE in order to use the admin application.

auth

• auth.E001: REQUIRED_FIELDS must be a list or tuple.
• auth.E002: The field named as the USERNAME_FIELD for a custom usermodel must not be included in REQUIRED_FIELDS.
• auth.E003: <field> must be unique because it is named as theUSERNAME_FIELD.
• auth.W004: <field> is named as the USERNAME_FIELD, but it is notunique.
• auth.E005: The permission codenamed <codename> clashes with a builtinpermission for model <model>.
• auth.E006: The permission codenamed <codename> is duplicated for model<model>.
• auth.E007: The verbose_name of model <model> must be at most244 characters for its builtin permission namesto be at most 255 characters.
• auth.E008: The permission named <name> of model <model> is longerthan 255 characters.
• auth.C009: <User model>.is_anonymous must be an attribute or propertyrather than a method. Ignoring this is a security issue as anonymous userswill be treated as authenticated!
• auth.C010: <User model>.is_authenticated must be an attribute orproperty rather than a method. Ignoring this is a security issue as anonymoususers will be treated as authenticated!

contenttypes

The following checks are performed when a model contains aGenericForeignKey orGenericRelation:

• contenttypes.E001: The GenericForeignKey object ID references thenonexistent field <field>.
• contenttypes.E002: The GenericForeignKey content type references thenonexistent field <field>.
• contenttypes.E003: <field> is not a ForeignKey.
• contenttypes.E004: <field> is not a ForeignKey tocontenttypes.ContentType.
• contenttypes.E005: Model names must be at most 100 characters.

postgres

The following checks are performed on django.contrib.postgres modelfields:

• postgres.E001: Base field for array has errors: …
• postgres.E002: Base field for array cannot be a related field.
• postgres.E003: <field> default should be a callable instead of aninstance so that it's not shared between all field instances.

sites

The following checks are performed on any model using aCurrentSiteManager:

• sites.E001: CurrentSiteManager could not find a field named<field name>.
• sites.E002: CurrentSiteManager cannot use <field> as it is not aforeign key or a many-to-many field.

staticfiles

The following checks verify that django.contrib.staticfiles is correctlyconfigured:

• staticfiles.E001: The STATICFILES_DIRS setting is not a tupleor list.
• staticfiles.E002: The STATICFILES_DIRS setting should notcontain the STATIC_ROOT setting.
• staticfiles.E003: The prefix <prefix> in theSTATICFILES_DIRS setting must not end with a slash.