Do not overwrite Dockerfile if unchanged.

Author: gfraiteur

src/PostSharp.Engineering.BuildTools/Docker/AzureCliComponent.cs

@@ -10,7 +10,7 @@ public class AzureCliComponent : ContainerComponent
 
     public override ContainerComponentKind Kind => ContainerComponentKind.AzureCli;
 
-    public override void WriteDockerfile( StreamWriter writer )
+    public override void WriteDockerfile( TextWriter writer )
     {
         writer.WriteLine(
             """

src/PostSharp.Engineering.BuildTools/Docker/ContainerComponent.cs

@@ -13,7 +13,7 @@ public abstract class ContainerComponent : IComparable<ContainerComponent>
 
     public abstract ContainerComponentKind Kind { get; }
 
-    public abstract void WriteDockerfile( StreamWriter writer );
+    public abstract void WriteDockerfile( TextWriter writer );
 
     public virtual void AddRequirements( IReadOnlyList<ContainerComponent> components, Action<ContainerComponent> add ) { }
 

src/PostSharp.Engineering.BuildTools/Docker/ContainerRequirements.cs

@@ -3,6 +3,7 @@
 using JetBrains.Annotations;
 using PostSharp.Engineering.BuildTools.Build;
 using PostSharp.Engineering.BuildTools.ContinuousIntegration.Model;
+using PostSharp.Engineering.BuildTools.Utilities;
 using System;
 using System.Collections.Generic;
 using System.IO;
@@ -66,22 +67,24 @@ void Add( ContainerComponent c )
 
         var dockerfilePath = Path.Combine( context.RepoDirectory, "Dockerfile" );
         context.Console.WriteMessage( $"Writing '{dockerfilePath}'." );
-        using var dockerfile = File.CreateText( dockerfilePath );
+        using var dockerfileContent = new StringWriter();
 
         foreach ( var component in orderedComponents )
         {
             context.Console.WriteMessage( $"Processing container component '{component.Name}'." );
 
             if ( component.Kind != ContainerComponentKind.Prolog )
             {
-                dockerfile.WriteLine();
-                dockerfile.WriteLine();
-                dockerfile.WriteLine( $"# {component.Name}" );
+                dockerfileContent.WriteLine();
+                dockerfileContent.WriteLine();
+                dockerfileContent.WriteLine( $"# {component.Name}" );
             }
 
             component.PopulateContextDirectory( context, contextDirectory );
-            component.WriteDockerfile( dockerfile );
+            component.WriteDockerfile( dockerfileContent );
         }
+        
+        TextFileHelper.WriteIfDifferent( dockerfilePath, dockerfileContent.ToString(), context );
 
         return true;
     }

src/PostSharp.Engineering.BuildTools/Docker/DotNetComponent.cs

@@ -44,7 +44,7 @@ public override void AddRequirements( IReadOnlyList<ContainerComponent> componen
         }
     }
 
-    public override void WriteDockerfile( StreamWriter writer )
+    public override void WriteDockerfile( TextWriter writer )
     {
         if ( this.DotNetComponentKind == DotNetComponentKind.Sdk )
         {

src/PostSharp.Engineering.BuildTools/Docker/DotNetInstallerComponent.cs

@@ -10,7 +10,7 @@ public class DotNetInstallerComponent : ContainerComponent
 
     public override ContainerComponentKind Kind => ContainerComponentKind.DotNetInstaller;
 
-    public override void WriteDockerfile( StreamWriter writer )
+    public override void WriteDockerfile( TextWriter writer )
     {
         writer.WriteLine(
             """

src/PostSharp.Engineering.BuildTools/Docker/EpilogueComponent.cs

@@ -12,7 +12,7 @@ public class EpilogueComponent : ContainerComponent
 
     public override ContainerComponentKind Kind => ContainerComponentKind.Epilogue;
 
-    public override void WriteDockerfile( StreamWriter writer )
+    public override void WriteDockerfile( TextWriter writer )
     {
         writer.WriteLine(
             """

src/PostSharp.Engineering.BuildTools/Docker/GitComponent.cs

@@ -10,7 +10,7 @@ public class GitComponent : ContainerComponent
 
     public override ContainerComponentKind Kind => ContainerComponentKind.Git;
 
-    public override void WriteDockerfile( StreamWriter writer )
+    public override void WriteDockerfile( TextWriter writer )
     {
         writer.WriteLine(
             """

src/PostSharp.Engineering.BuildTools/Docker/PowershellComponent.cs

@@ -10,7 +10,7 @@ public class PowershellComponent : ContainerComponent
 
     public override ContainerComponentKind Kind => ContainerComponentKind.Powershell;
 
-    public override void WriteDockerfile( StreamWriter writer )
+    public override void WriteDockerfile( TextWriter writer )
     {
         writer.WriteLine(
             """

src/PostSharp.Engineering.BuildTools/Docker/PrologComponent.cs

@@ -10,7 +10,7 @@ public class PrologComponent : ContainerComponent
 
     public override ContainerComponentKind Kind => ContainerComponentKind.Prolog;
 
-    public override void WriteDockerfile( StreamWriter writer )
+    public override void WriteDockerfile( TextWriter writer )
     {
         writer.WriteLine(
             """

src/PostSharp.Engineering.BuildTools/Docker/VisualStudioBuildToolsComponent.cs

@@ -24,7 +24,7 @@ public VisualStudioBuildToolsComponent( string[] vsComponents )
         this._vsComponents = vsComponents;
     }
 
-    public override void WriteDockerfile( StreamWriter writer )
+    public override void WriteDockerfile( TextWriter writer )
     {
         var components = string.Join( ", ", this._vsComponents.Select( x => $"\"--add\", \"{x}\"" ) );