Merge remote-tracking branch 'upstream/master' into graph/enable-func…

…tional-tests

STYLEGUIDE.md

@@ -141,6 +141,39 @@ function addBar(foos, foo) {
 }
 ```
 
+### Avoid `any` whenever possible
+
+Since TypeScript 3.0 and the introduction of the
+[`unknown` type](https://mariusschulz.com/blog/the-unknown-type-in-typescript) there are rarely any
+reasons to use `any` as a type. Nearly all places of former `any` usage can be replace by either a
+generic or `unknown` (in cases the type is really not known).
+
+You should always prefer using those mechanisms over using `any`, since they are stricter typed and
+less likely to introduce bugs in the future due to insufficient types.
+
+If you’re not having `any` in your plugin or are starting a new plugin, you should enable the
+[`@typescript-eslint/no-explicit-any`](https://github.com/typescript-eslint/typescript-eslint/blob/master/packages/eslint-plugin/docs/rules/no-explicit-any.md)
+linting rule for your plugin via the [`.eslintrc.js`](https://github.com/elastic/kibana/blob/master/.eslintrc.js) config.
+
+### Avoid non-null assertions
+
+You should try avoiding non-null assertions (`!.`) wherever possible. By using them you tell
+TypeScript, that something is not null even though by it’s type it could be. Usage of non-null
+assertions is most often a side-effect of you actually checked that the variable is not `null`
+but TypeScript doesn’t correctly carry on that information till the usage of the variable.
+
+In most cases it’s possible to replace the non-null assertion by structuring your code/checks slightly different
+or using [user defined type guards](https://www.typescriptlang.org/docs/handbook/advanced-types.html#user-defined-type-guards)
+to properly tell TypeScript what type a variable has.
+
+Using non-null assertion increases the risk for future bugs. In case the condition under which we assumed that the
+variable can’t be null has changed (potentially even due to changes in compeltely different files), the non-null
+assertion would now wrongly disable proper type checking for us.
+
+If you’re not using non-null assertions in your plugin or are starting a new plugin, consider enabling the
+[`@typescript-eslint/no-non-null-assertion`](https://github.com/typescript-eslint/typescript-eslint/blob/master/packages/eslint-plugin/docs/rules/no-non-null-assertion.md)
+linting rule for you plugin in the [`.eslintrc.js`](https://github.com/elastic/kibana/blob/master/.eslintrc.js) config.
+
 ### Return/throw early from functions
 
 To avoid deep nesting of if-statements, always return a function's value as early

docs/development/core/public/kibana-plugin-public.applicationsetup.registermountcontext.md

@@ -9,15 +9,15 @@ Register a context provider for application mounting. Will only be available to
 <b>Signature:</b>
 
 ```typescript
-registerMountContext<T extends keyof AppMountContext>(contextName: T, provider: IContextProvider<AppMountContext, T>): void;
+registerMountContext<T extends keyof AppMountContext>(contextName: T, provider: IContextProvider<App['mount'], T>): void;
 ```
 
 ## Parameters
 
 |  Parameter | Type | Description |
 |  --- | --- | --- |
 |  contextName | <code>T</code> | The key of [AppMountContext](./kibana-plugin-public.appmountcontext.md) this provider's return value should be attached to. |
-|  provider | <code>IContextProvider&lt;AppMountContext, T&gt;</code> | A [IContextProvider](./kibana-plugin-public.icontextprovider.md) function |
+|  provider | <code>IContextProvider&lt;App['mount'], T&gt;</code> | A [IContextProvider](./kibana-plugin-public.icontextprovider.md) function |
 
 <b>Returns:</b>
 

docs/development/core/public/kibana-plugin-public.applicationstart.registermountcontext.md

@@ -9,15 +9,15 @@ Register a context provider for application mounting. Will only be available to
 <b>Signature:</b>
 
 ```typescript
-registerMountContext<T extends keyof AppMountContext>(contextName: T, provider: IContextProvider<AppMountContext, T>): void;
+registerMountContext<T extends keyof AppMountContext>(contextName: T, provider: IContextProvider<App['mount'], T>): void;
 ```
 
 ## Parameters
 
 |  Parameter | Type | Description |
 |  --- | --- | --- |
 |  contextName | <code>T</code> | The key of [AppMountContext](./kibana-plugin-public.appmountcontext.md) this provider's return value should be attached to. |
-|  provider | <code>IContextProvider&lt;AppMountContext, T&gt;</code> | A [IContextProvider](./kibana-plugin-public.icontextprovider.md) function |
+|  provider | <code>IContextProvider&lt;App['mount'], T&gt;</code> | A [IContextProvider](./kibana-plugin-public.icontextprovider.md) function |
 
 <b>Returns:</b>
 

docs/development/core/public/kibana-plugin-public.contextsetup.createcontextcontainer.md

@@ -9,9 +9,9 @@ Creates a new [IContextContainer](./kibana-plugin-public.icontextcontainer.md) f
 <b>Signature:</b>
 
 ```typescript
-createContextContainer<TContext extends {}, THandlerReturn, THandlerParmaters extends any[] = []>(): IContextContainer<TContext, THandlerReturn, THandlerParmaters>;
+createContextContainer<THandler extends HandlerFunction<any>>(): IContextContainer<THandler>;
 ```
 <b>Returns:</b>
 
-`IContextContainer<TContext, THandlerReturn, THandlerParmaters>`
+`IContextContainer<THandler>`
 

docs/development/core/public/kibana-plugin-public.handlercontexttype.md

@@ -0,0 +1,13 @@
+<!-- Do not edit this file. It is automatically generated by API Documenter. -->
+
+[Home](./index.md) &gt; [kibana-plugin-public](./kibana-plugin-public.md) &gt; [HandlerContextType](./kibana-plugin-public.handlercontexttype.md)
+
+## HandlerContextType type
+
+Extracts the type of the first argument of a [HandlerFunction](./kibana-plugin-public.handlerfunction.md) to represent the type of the context.
+
+<b>Signature:</b>
+
+```typescript
+export declare type HandlerContextType<T extends HandlerFunction<any>> = T extends HandlerFunction<infer U> ? U : never;
+```

docs/development/core/public/kibana-plugin-public.handlerfunction.md

@@ -0,0 +1,13 @@
+<!-- Do not edit this file. It is automatically generated by API Documenter. -->
+
+[Home](./index.md) &gt; [kibana-plugin-public](./kibana-plugin-public.md) &gt; [HandlerFunction](./kibana-plugin-public.handlerfunction.md)
+
+## HandlerFunction type
+
+A function that accepts a context object and an optional number of additional arguments. Used for the generic types in [IContextContainer](./kibana-plugin-public.icontextcontainer.md)
+
+<b>Signature:</b>
+
+```typescript
+export declare type HandlerFunction<T extends object> = (context: T, ...args: any[]) => any;
+```

docs/development/core/public/kibana-plugin-public.handlerparameters.md

@@ -0,0 +1,13 @@
+<!-- Do not edit this file. It is automatically generated by API Documenter. -->
+
+[Home](./index.md) &gt; [kibana-plugin-public](./kibana-plugin-public.md) &gt; [HandlerParameters](./kibana-plugin-public.handlerparameters.md)
+
+## HandlerParameters type
+
+Extracts the types of the additional arguments of a [HandlerFunction](./kibana-plugin-public.handlerfunction.md)<!-- -->, excluding the [HandlerContextType](./kibana-plugin-public.handlercontexttype.md)<!-- -->.
+
+<b>Signature:</b>
+
+```typescript
+export declare type HandlerParameters<T extends HandlerFunction<any>> = T extends (context: any, ...args: infer U) => any ? U : never;
+```

docs/development/core/public/kibana-plugin-public.icontextcontainer.createhandler.md

@@ -9,19 +9,19 @@ Create a new handler function pre-wired to context for the plugin.
 <b>Signature:</b>
 
 ```typescript
-createHandler(pluginOpaqueId: PluginOpaqueId, handler: IContextHandler<TContext, THandlerReturn, THandlerParameters>): (...rest: THandlerParameters) => THandlerReturn extends Promise<any> ? THandlerReturn : Promise<THandlerReturn>;
+createHandler(pluginOpaqueId: PluginOpaqueId, handler: THandler): (...rest: HandlerParameters<THandler>) => ShallowPromise<ReturnType<THandler>>;
 ```
 
 ## Parameters
 
 |  Parameter | Type | Description |
 |  --- | --- | --- |
 |  pluginOpaqueId | <code>PluginOpaqueId</code> | The plugin opaque ID for the plugin that registers this handler. |
-|  handler | <code>IContextHandler&lt;TContext, THandlerReturn, THandlerParameters&gt;</code> | Handler function to pass context object to. |
+|  handler | <code>THandler</code> | Handler function to pass context object to. |
 
 <b>Returns:</b>
 
-`(...rest: THandlerParameters) => THandlerReturn extends Promise<any> ? THandlerReturn : Promise<THandlerReturn>`
+`(...rest: HandlerParameters<THandler>) => ShallowPromise<ReturnType<THandler>>`
 
 A function that takes `THandlerParameters`<!-- -->, calls `handler` with a new context, and returns a Promise of the `handler` return value.
 

docs/development/core/public/kibana-plugin-public.icontextcontainer.md

@@ -9,7 +9,7 @@ An object that handles registration of context providers and configuring handler
 <b>Signature:</b>
 
 ```typescript
-export interface IContextContainer<TContext extends {}, THandlerReturn, THandlerParameters extends any[] = []> 
+export interface IContextContainer<THandler extends HandlerFunction<any>> 
 ```
 
 ## Methods

docs/development/core/public/kibana-plugin-public.icontextcontainer.registercontext.md

@@ -9,7 +9,7 @@ Register a new context provider.
 <b>Signature:</b>
 
 ```typescript
-registerContext<TContextName extends keyof TContext>(pluginOpaqueId: PluginOpaqueId, contextName: TContextName, provider: IContextProvider<TContext, TContextName, THandlerParameters>): this;
+registerContext<TContextName extends keyof HandlerContextType<THandler>>(pluginOpaqueId: PluginOpaqueId, contextName: TContextName, provider: IContextProvider<THandler, TContextName>): this;
 ```
 
 ## Parameters
@@ -18,7 +18,7 @@ registerContext<TContextName extends keyof TContext>(pluginOpaqueId: PluginOpaqu
 |  --- | --- | --- |
 |  pluginOpaqueId | <code>PluginOpaqueId</code> | The plugin opaque ID for the plugin that registers this context. |
 |  contextName | <code>TContextName</code> | The key of the <code>TContext</code> object this provider supplies the value for. |
-|  provider | <code>IContextProvider&lt;TContext, TContextName, THandlerParameters&gt;</code> | A [IContextProvider](./kibana-plugin-public.icontextprovider.md) to be called each time a new context is created. |
+|  provider | <code>IContextProvider&lt;THandler, TContextName&gt;</code> | A [IContextProvider](./kibana-plugin-public.icontextprovider.md) to be called each time a new context is created. |
 
 <b>Returns:</b>
 

docs/development/core/public/kibana-plugin-public.icontextprovider.md

@@ -9,7 +9,7 @@ A function that returns a context value for a specific key of given context type
 <b>Signature:</b>
 
 ```typescript
-export declare type IContextProvider<TContext extends Record<string, any>, TContextName extends keyof TContext, TProviderParameters extends any[] = []> = (context: Partial<TContext>, ...rest: TProviderParameters) => Promise<TContext[TContextName]> | TContext[TContextName];
+export declare type IContextProvider<THandler extends HandlerFunction<any>, TContextName extends keyof HandlerContextType<THandler>> = (context: Partial<HandlerContextType<THandler>>, ...rest: HandlerParameters<THandler>) => Promise<HandlerContextType<THandler>[TContextName]> | HandlerContextType<THandler>[TContextName];
 ```
 
 ## Remarks

docs/development/core/public/kibana-plugin-public.md

@@ -91,11 +91,13 @@ The plugin integrates with the core system via lifecycle events: `setup`<!-- -->
 |  [AppUnmount](./kibana-plugin-public.appunmount.md) | A function called when an application should be unmounted from the page. This function should be synchronous. |
 |  [ChromeHelpExtension](./kibana-plugin-public.chromehelpextension.md) |  |
 |  [ChromeNavLinkUpdateableFields](./kibana-plugin-public.chromenavlinkupdateablefields.md) |  |
+|  [HandlerContextType](./kibana-plugin-public.handlercontexttype.md) | Extracts the type of the first argument of a [HandlerFunction](./kibana-plugin-public.handlerfunction.md) to represent the type of the context. |
+|  [HandlerFunction](./kibana-plugin-public.handlerfunction.md) | A function that accepts a context object and an optional number of additional arguments. Used for the generic types in [IContextContainer](./kibana-plugin-public.icontextcontainer.md) |
+|  [HandlerParameters](./kibana-plugin-public.handlerparameters.md) | Extracts the types of the additional arguments of a [HandlerFunction](./kibana-plugin-public.handlerfunction.md)<!-- -->, excluding the [HandlerContextType](./kibana-plugin-public.handlercontexttype.md)<!-- -->. |
 |  [HttpBody](./kibana-plugin-public.httpbody.md) |  |
 |  [HttpHandler](./kibana-plugin-public.httphandler.md) |  |
 |  [HttpSetup](./kibana-plugin-public.httpsetup.md) |  |
 |  [HttpStart](./kibana-plugin-public.httpstart.md) |  |
-|  [IContextHandler](./kibana-plugin-public.icontexthandler.md) | A function registered by a plugin to perform some action. |
 |  [IContextProvider](./kibana-plugin-public.icontextprovider.md) | A function that returns a context value for a specific key of given context type. |
 |  [OverlayBannerMount](./kibana-plugin-public.overlaybannermount.md) | A function that will mount the banner inside the provided element. |
 |  [OverlayBannerUnmount](./kibana-plugin-public.overlaybannerunmount.md) | A function that will unmount the banner from the element. |

docs/development/core/server/kibana-plugin-server.basepath.get.md

@@ -9,5 +9,5 @@ returns `basePath` value, specific for an incoming request.
 <b>Signature:</b>
 
 ```typescript
-get: (request: KibanaRequest<unknown, unknown, unknown> | LegacyRequest) => string;
+get: (request: LegacyRequest | KibanaRequest<unknown, unknown, unknown>) => string;
 ```

docs/development/core/server/kibana-plugin-server.basepath.md

@@ -16,11 +16,11 @@ export declare class BasePath
 
 |  Property | Modifiers | Type | Description |
 |  --- | --- | --- | --- |
-|  [get](./kibana-plugin-server.basepath.get.md) |  | <code>(request: KibanaRequest&lt;unknown, unknown, unknown&gt; &#124; LegacyRequest) =&gt; string</code> | returns <code>basePath</code> value, specific for an incoming request. |
+|  [get](./kibana-plugin-server.basepath.get.md) |  | <code>(request: LegacyRequest &#124; KibanaRequest&lt;unknown, unknown, unknown&gt;) =&gt; string</code> | returns <code>basePath</code> value, specific for an incoming request. |
 |  [prepend](./kibana-plugin-server.basepath.prepend.md) |  | <code>(path: string) =&gt; string</code> | returns a new <code>basePath</code> value, prefixed with passed <code>url</code>. |
 |  [remove](./kibana-plugin-server.basepath.remove.md) |  | <code>(path: string) =&gt; string</code> | returns a new <code>basePath</code> value, cleaned up from passed <code>url</code>. |
 |  [serverBasePath](./kibana-plugin-server.basepath.serverbasepath.md) |  | <code>string</code> | returns the server's basePath<!-- -->See [BasePath.get](./kibana-plugin-server.basepath.get.md) for getting the basePath value for a specific request |
-|  [set](./kibana-plugin-server.basepath.set.md) |  | <code>(request: KibanaRequest&lt;unknown, unknown, unknown&gt; &#124; LegacyRequest, requestSpecificBasePath: string) =&gt; void</code> | sets <code>basePath</code> value, specific for an incoming request. |
+|  [set](./kibana-plugin-server.basepath.set.md) |  | <code>(request: LegacyRequest &#124; KibanaRequest&lt;unknown, unknown, unknown&gt;, requestSpecificBasePath: string) =&gt; void</code> | sets <code>basePath</code> value, specific for an incoming request. |
 
 ## Remarks
 

docs/development/core/server/kibana-plugin-server.basepath.set.md

@@ -9,5 +9,5 @@ sets `basePath` value, specific for an incoming request.
 <b>Signature:</b>
 
 ```typescript
-set: (request: KibanaRequest<unknown, unknown, unknown> | LegacyRequest, requestSpecificBasePath: string) => void;
+set: (request: LegacyRequest | KibanaRequest<unknown, unknown, unknown>, requestSpecificBasePath: string) => void;
 ```

docs/development/core/server/kibana-plugin-server.contextsetup.createcontextcontainer.md

@@ -9,9 +9,9 @@ Creates a new [IContextContainer](./kibana-plugin-server.icontextcontainer.md) f
 <b>Signature:</b>
 
 ```typescript
-createContextContainer<TContext extends {}, THandlerReturn, THandlerParmaters extends any[] = []>(): IContextContainer<TContext, THandlerReturn, THandlerParmaters>;
+createContextContainer<THandler extends HandlerFunction<any>>(): IContextContainer<THandler>;
 ```
 <b>Returns:</b>
 
-`IContextContainer<TContext, THandlerReturn, THandlerParmaters>`
+`IContextContainer<THandler>`
 

docs/development/core/server/kibana-plugin-server.coresetup.http.md

@@ -14,7 +14,7 @@ http: {
         registerOnPostAuth: HttpServiceSetup['registerOnPostAuth'];
         basePath: HttpServiceSetup['basePath'];
         isTlsEnabled: HttpServiceSetup['isTlsEnabled'];
-        registerRouteHandlerContext: <T extends keyof RequestHandlerContext>(name: T, provider: RequestHandlerContextProvider<RequestHandlerContext>) => RequestHandlerContextContainer<RequestHandlerContext>;
+        registerRouteHandlerContext: <T extends keyof RequestHandlerContext>(name: T, provider: RequestHandlerContextProvider<T>) => RequestHandlerContextContainer;
         createRouter: () => IRouter;
     };
 ```

docs/development/core/server/kibana-plugin-server.coresetup.md

@@ -18,5 +18,5 @@ export interface CoreSetup
 |  --- | --- | --- |
 |  [context](./kibana-plugin-server.coresetup.context.md) | <code>{</code><br/><code>        createContextContainer: ContextSetup['createContextContainer'];</code><br/><code>    }</code> |  |
 |  [elasticsearch](./kibana-plugin-server.coresetup.elasticsearch.md) | <code>{</code><br/><code>        adminClient$: Observable&lt;ClusterClient&gt;;</code><br/><code>        dataClient$: Observable&lt;ClusterClient&gt;;</code><br/><code>        createClient: (type: string, clientConfig?: Partial&lt;ElasticsearchClientConfig&gt;) =&gt; ClusterClient;</code><br/><code>    }</code> |  |
-|  [http](./kibana-plugin-server.coresetup.http.md) | <code>{</code><br/><code>        createCookieSessionStorageFactory: HttpServiceSetup['createCookieSessionStorageFactory'];</code><br/><code>        registerOnPreAuth: HttpServiceSetup['registerOnPreAuth'];</code><br/><code>        registerAuth: HttpServiceSetup['registerAuth'];</code><br/><code>        registerOnPostAuth: HttpServiceSetup['registerOnPostAuth'];</code><br/><code>        basePath: HttpServiceSetup['basePath'];</code><br/><code>        isTlsEnabled: HttpServiceSetup['isTlsEnabled'];</code><br/><code>        registerRouteHandlerContext: &lt;T extends keyof RequestHandlerContext&gt;(name: T, provider: RequestHandlerContextProvider&lt;RequestHandlerContext&gt;) =&gt; RequestHandlerContextContainer&lt;RequestHandlerContext&gt;;</code><br/><code>        createRouter: () =&gt; IRouter;</code><br/><code>    }</code> |  |
+|  [http](./kibana-plugin-server.coresetup.http.md) | <code>{</code><br/><code>        createCookieSessionStorageFactory: HttpServiceSetup['createCookieSessionStorageFactory'];</code><br/><code>        registerOnPreAuth: HttpServiceSetup['registerOnPreAuth'];</code><br/><code>        registerAuth: HttpServiceSetup['registerAuth'];</code><br/><code>        registerOnPostAuth: HttpServiceSetup['registerOnPostAuth'];</code><br/><code>        basePath: HttpServiceSetup['basePath'];</code><br/><code>        isTlsEnabled: HttpServiceSetup['isTlsEnabled'];</code><br/><code>        registerRouteHandlerContext: &lt;T extends keyof RequestHandlerContext&gt;(name: T, provider: RequestHandlerContextProvider&lt;T&gt;) =&gt; RequestHandlerContextContainer;</code><br/><code>        createRouter: () =&gt; IRouter;</code><br/><code>    }</code> |  |
 

docs/development/core/server/kibana-plugin-server.handlercontexttype.md

@@ -0,0 +1,13 @@
+<!-- Do not edit this file. It is automatically generated by API Documenter. -->
+
+[Home](./index.md) &gt; [kibana-plugin-server](./kibana-plugin-server.md) &gt; [HandlerContextType](./kibana-plugin-server.handlercontexttype.md)
+
+## HandlerContextType type
+
+Extracts the type of the first argument of a [HandlerFunction](./kibana-plugin-server.handlerfunction.md) to represent the type of the context.
+
+<b>Signature:</b>
+
+```typescript
+export declare type HandlerContextType<T extends HandlerFunction<any>> = T extends HandlerFunction<infer U> ? U : never;
+```

docs/development/core/server/kibana-plugin-server.handlerfunction.md

@@ -0,0 +1,13 @@
+<!-- Do not edit this file. It is automatically generated by API Documenter. -->
+
+[Home](./index.md) &gt; [kibana-plugin-server](./kibana-plugin-server.md) &gt; [HandlerFunction](./kibana-plugin-server.handlerfunction.md)
+
+## HandlerFunction type
+
+A function that accepts a context object and an optional number of additional arguments. Used for the generic types in [IContextContainer](./kibana-plugin-server.icontextcontainer.md)
+
+<b>Signature:</b>
+
+```typescript
+export declare type HandlerFunction<T extends object> = (context: T, ...args: any[]) => any;
+```