Add coverage for analyzer violation BL0007 (#35161)

Author: guardrex

aspnetcore/blazor/components/index.md

@@ -1071,14 +1071,14 @@ For more information, see <xref:mvc/views/razor>.
 > [!WARNING]
 > Providing initial values for component parameters is supported, but don't create a component that writes to its own parameters after the component is rendered for the first time. For more information, see <xref:blazor/components/overwriting-parameters>.
 
-Component parameters should be declared as *auto-properties*, meaning that they shouldn't contain custom logic in their `get` or `set` accessors. For example, the following `StartData` property is an auto-property:
+Component parameters should be declared as [automatically-implemented properties (*auto properties*)](/dotnet/csharp/programming-guide/classes-and-structs/auto-implemented-properties), meaning that they shouldn't contain custom logic in their `get` or `set` accessors. For example, the following `StartData` property is an auto property:
 
 ```csharp
 [Parameter]
 public DateTime StartData { get; set; }
 ```
 
-Don't place custom logic in the `get` or `set` accessor because component parameters are purely intended for use as a channel for a parent component to flow information to a child component. If a `set` accessor of a child component property contains logic that causes rerendering of the parent component, an infinite rendering loop results.
+Don't place custom logic in the `get` or `set` accessor because component parameters are purely intended for use as a channel for a parent component to flow information to a child component. If a `set` accessor of a child component property contains logic that causes rerendering of the parent component, an infinite rendering loop results. Other side effects include unexpected extra renderings and parameter value overwrites.
 
 To transform a received parameter value:
 

aspnetcore/diagnostics/bl0001.md

@@ -1,7 +1,7 @@
 ---
 title: "BL0001: Component parameter should have public setters"
 description: "Learn about analysis rule BL0001: Component parameter should have public setters"
-author: pranavkm
+author: guardrex
 monikerRange: '>= aspnetcore-3.1'
 ms.author: riande
 ms.date: 10/21/2021

aspnetcore/diagnostics/bl0002.md

@@ -1,7 +1,7 @@
 ---
 title: "BL0002: Component has multiple CaptureUnmatchedValues parameters"
 description: "Learn about analysis rule BL0002: Component has multiple CaptureUnmatchedValues parameters"
-author: pranavkm
+author: guardrex
 monikerRange: '>= aspnetcore-3.1'
 ms.author: riande
 ms.date: 10/21/2021

aspnetcore/diagnostics/bl0003.md

@@ -1,7 +1,7 @@
 ---
 title: "BL0003: Component parameter with CaptureUnmatchedValues has the wrong type"
 description: "Learn about analysis rule BL0003: Component parameter with CaptureUnmatchedValues has the wrong type"
-author: pranavkm
+author: guardrex
 monikerRange: '>= aspnetcore-3.1'
 ms.author: riande
 ms.date: 10/21/2021

aspnetcore/diagnostics/bl0004.md

@@ -1,7 +1,7 @@
 ---
 title: "BL0004: Component parameter should be public"
 description: "Learn about analysis rule BL0004: Component parameter should be public"
-author: pranavkm
+author: guardrex
 monikerRange: '>= aspnetcore-3.1'
 ms.author: riande
 ms.date: 10/21/2021

aspnetcore/diagnostics/bl0005.md

@@ -1,7 +1,7 @@
 ---
 title: "BL0005: Component parameter should not be set outside of its component"
 description: "Learn about analysis rule BL0005: Component parameter should not be set outside of its component"
-author: pranavkm
+author: guardrex
 monikerRange: '>= aspnetcore-3.1'
 ms.author: riande
 ms.date: 10/21/2021

aspnetcore/diagnostics/bl0006.md

@@ -1,7 +1,7 @@
 ---
 title: "BL0006: Do not use RenderTree types"
 description: "Learn about analysis rule BL0006: Do not use RenderTree types"
-author: pranavkm
+author: guardrex
 monikerRange: '>= aspnetcore-3.1'
 ms.author: riande
 ms.date: 10/21/2021

aspnetcore/diagnostics/bl0007.md

@@ -0,0 +1,34 @@
+---
+title: "BL0007: Component parameter '{0}' should be auto property"
+description: "Learn about analysis rule BL0007: Component parameter '{0}' should be auto property"
+author: guardrex
+monikerRange: '>= aspnetcore-3.1'
+ms.author: riande
+ms.date: 04/07/2025
+uid: diagnostics/bl0007
+---
+# BL0007: Component parameter '{0}' should be auto property
+
+|                                     | Value        |
+| -                                   | -            |
+| **Rule ID**                         | BL0007       |
+| **Category**                        | Usage        |
+| **Fix is breaking or non-breaking** | Non-breaking |
+
+## Cause
+
+A [component parameter](xref:blazor/components/index#component-parameters), which is a public [C# property](/dotnet/csharp/programming-guide/classes-and-structs/properties) of a component class with the [`[Parameter]` attribute](xref:Microsoft.AspNetCore.Components.ParameterAttribute), isn't an [automatically-implemented property (*auto property*)](/dotnet/csharp/programming-guide/classes-and-structs/auto-implemented-properties).
+
+## Rule description
+
+A component parameter is a framework-managed communication channel between a parent and a child component. Developers shouldn't read or write to the parameter in a [`get` (getter) or `set` (setter) accessor](/dotnet/csharp/programming-guide/classes-and-structs/using-properties), either from inside or outside the component.
+
+Possible side effects of interacting directly with a component parameter include infinite rendering loops, unexpected extra renderings, and parameter value overwrites.
+
+## How to fix violations
+
+Implement the component parameter as an auto property and override <xref:Microsoft.AspNetCore.Components.ComponentBase.OnParametersSet%2A> or <xref:Microsoft.AspNetCore.Components.ComponentBase.OnParametersSetAsync%2A> in the component class to read or transform the parameter's value. For more information, see the [`OnParametersSet{Async}` lifecycle method](xref:blazor/components/lifecycle#after-parameters-are-set-onparameterssetasync).
+
+## When to suppress warnings
+
+Do not suppress a warning from this rule.

aspnetcore/diagnostics/code-analysis.md

@@ -49,6 +49,7 @@ Diagnostic ID:
 * [BL0004](xref:diagnostics/bl0004)
 * [BL0005](xref:diagnostics/bl0005)
 * [BL0006](xref:diagnostics/bl0006)
+* [BL0007](xref:diagnostics/bl0007)
 * [MVC1000](xref:diagnostics/mvc1000)
 * [MVC1001](xref:diagnostics/mvc1001)
 * [MVC1002](xref:diagnostics/mvc1002)

aspnetcore/toc.yml

@@ -1461,6 +1461,8 @@ items:
         uid: diagnostics/bl0005
       - name: BL0006
         uid: diagnostics/bl0006
+      - name: BL0007
+        uid: diagnostics/bl0007
       - name: MVC1000
         uid: diagnostics/mvc1000
       - name: MVC1001