Notify MSBuild TerminalLogger of project cache plugin starting

src/MSBuild/Resources/Strings.resx

@@ -1184,6 +1184,13 @@
   <data name="PossiblyOmittedMaxCPUSwitch" xml:space="preserve">
     <value>Building the projects in this solution one at a time. To enable parallel build, please add the "-m" switch.</value>
   </data>
+  <data name="CachePluginProjectFinished_OutputPath" xml:space="preserve">
+    <value> -> {0}</value>
+    <comment>
+      Info about project output - when known. Printed after ProjectFinished_NoTF or ProjectFinished_WithTF.
+      {0}: VT100 coded hyperlink to project output directory
+    </comment>
+  </data>
   <data name="ProjectSchemaErrorHalt" xml:space="preserve">
     <value>MSBUILD : MSB1045: Stopping because of syntax errors in project file.</value>
     <comment>{StrBegin="MSBUILD : MSB1045: "}</comment>

src/MSBuild/TerminalLogger/Project.cs

@@ -51,6 +51,11 @@ public Project(string? targetFramework, StopwatchAbstraction? stopwatch)
     /// </summary>
     public bool IsTestProject { get; set; }
 
+    /// <summary>
+    /// True when the project has run target with name "_CachePluginRunStart" defined in <see cref="TerminalLogger._cachePluginStartTarget"/>.
+    /// </summary>
+    public bool IsCachePluginProject { get; set; }
+
     /// <summary>
     /// A lazily initialized list of build messages/warnings/errors raised during the build.
     /// </summary>

src/MSBuild/TerminalLogger/TerminalLogger.cs

@@ -200,6 +200,11 @@ public ProjectContext(BuildEventContext context)
     /// </summary>
     private DateTime? _testEndTime;
 
+    /// <summary>
+    /// Name of target that identifies the project cache plugin run has just started.
+    /// </summary>
+    private static string _cachePluginStartTarget = "_CachePluginRunStart";
+
     /// <summary>
     /// Whether to show TaskCommandLineEventArgs high-priority messages. 
     /// </summary>
@@ -630,7 +635,8 @@ private void ProjectFinished(object sender, ProjectFinishedEventArgs e)
                                 }
                             }
 
-                            Terminal.WriteLine(ResourceUtilities.FormatResourceStringIgnoreCodeAndKeyword("ProjectFinished_OutputPath",
+                            string resourceName = project.IsCachePluginProject ? "CachePluginProjectFinished_OutputPath" : "ProjectFinished_OutputPath";
+                            Terminal.WriteLine(ResourceUtilities.FormatResourceStringIgnoreCodeAndKeyword(resourceName,
                                 $"{AnsiCodes.LinkPrefix}{urlString}{AnsiCodes.LinkInfix}{outputPathSpan.ToString()}{AnsiCodes.LinkSuffix}"));
                         }
                         else
@@ -673,12 +679,16 @@ private void TargetStarted(object sender, TargetStartedEventArgs e)
 
             string projectFile = Path.GetFileNameWithoutExtension(e.ProjectFile);
 
+            string targetName = e.TargetName;
+            if (targetName == _cachePluginStartTarget)
+            {
+                project.IsCachePluginProject = true;
+            }
 
-            var isTestTarget = e.TargetName == _testStartTarget;
-
-            var targetName = isTestTarget ? "Testing" : e.TargetName;
-            if (isTestTarget)
+            if (targetName == _testStartTarget)
             {
+                targetName = "Testing";
+
                 // Use the minimal start time, so if we run tests in parallel, we can calculate duration
                 // as this start time, minus time when tests finished.
                 _testStartTime = _testStartTime == null
@@ -931,7 +941,7 @@ private void ErrorRaised(object sender, BuildErrorEventArgs e)
         }
     }
 
-    #endregion
+#endregion
 
     #region Refresher thread implementation