Add -NoCache switch and improve error handling in Build.ps1

- Add -NoCache parameter to force rebuild bypassing cache
- Re-find output DLL after build to handle first-time builds
- Improve error messages to show expected DLL path
- Update header to clarify this is an auto-generated file

Author: gfraiteur

Build.ps1

@@ -1,10 +1,12 @@
-# The original of this file is in the PostSharp.Engineering repo.
-# You can generate this file using `./Build.ps1 generate-scripts`.
+# *** DO NOT EDIT THIS FILE DIRECTLY ***
+# This file is auto-generated from src/PostSharp.Engineering.BuildTools/Resources/Build.ps1
+# Edit the source version, then run `./Build.ps1 generate-scripts` to regenerate this file.
 
 [CmdletBinding(PositionalBinding = $false)]
 param(
     [switch]$Interactive, # Opens an interactive PowerShell session
     [switch]$StartVsmon, # Enable the remote debugger.
+    [switch]$NoCache, # Bypass the build cache for `eng`, and force a rebuild.
     [Parameter(ValueFromRemainingArguments)]
     [string[]]$BuildArgs   # Arguments passed to `Build.ps1` within the container.
 )
@@ -57,7 +59,12 @@ if (-not $Interactive -or $BuildArgs)
 
         $needsBuild = $false
 
-        if (-not $outputDll -or -not (Test-Path $outputDll))
+        if ($NoCache)
+        {
+            # Cache bypassed by -NoCache switch
+            $needsBuild = $true
+        }
+        elseif (-not $outputDll -or -not (Test-Path $outputDll))
         {
             # DLL doesn't exist, need to build
             $needsBuild = $true
@@ -91,18 +98,28 @@ if (-not $Interactive -or $BuildArgs)
         if ($needsBuild)
         {
             # Build is needed
-            Write-Host "Build cache invalid, rebuilding..." -ForegroundColor Cyan
+            Write-Host "Rebuilding Build$ProductName..." -ForegroundColor Cyan
             & dotnet build $projectPath
             if ($LASTEXITCODE -ne 0)
             {
                 throw "Build failed with exit code $LASTEXITCODE"
             }
 
+            # Re-find the output DLL after build
+            if (Test-Path $binDebugPath)
+            {
+                $outputDll = Get-ChildItem -Path $binDebugPath -Filter "Build$ProductName.dll" -Recurse -ErrorAction SilentlyContinue | Select-Object -First 1 | ForEach-Object { $_.FullName }
+            }
+
             # Update the DLL timestamp to mark the cache as valid
             if ($outputDll -and (Test-Path $outputDll))
             {
                 (Get-Item $outputDll).LastWriteTime = Get-Date
             }
+            else
+            {
+                throw "Build succeeded but output DLL '$outputDll' not found."
+            }
         }
         else
         {
@@ -112,7 +129,7 @@ if (-not $Interactive -or $BuildArgs)
         # Run the project using dotnet exec (faster than dotnet run)
         if (-not $outputDll -or -not (Test-Path $outputDll))
         {
-            throw "Output DLL not found at: $outputDll"
+            throw "Output DLL not found. Expected path: '$outputDll'."
         }
 
         & dotnet exec $outputDll $BuildArgs

src/PostSharp.Engineering.BuildTools/Resources/Build.ps1

@@ -1,10 +1,12 @@
-# The original of this file is in the PostSharp.Engineering repo.
-# You can generate this file using `./Build.ps1 generate-scripts`.
+# *** DO NOT EDIT THIS FILE DIRECTLY ***
+# This file is auto-generated from src/PostSharp.Engineering.BuildTools/Resources/Build.ps1
+# Edit the source version, then run `./Build.ps1 generate-scripts` to regenerate this file.
 
 [CmdletBinding(PositionalBinding = $false)]
 param(
     [switch]$Interactive, # Opens an interactive PowerShell session
     [switch]$StartVsmon, # Enable the remote debugger.
+    [switch]$NoCache, # Bypass the build cache for `eng`, and force a rebuild.
     [Parameter(ValueFromRemainingArguments)]
     [string[]]$BuildArgs   # Arguments passed to `Build.ps1` within the container.
 )
@@ -57,7 +59,12 @@ if (-not $Interactive -or $BuildArgs)
 
         $needsBuild = $false
 
-        if (-not $outputDll -or -not (Test-Path $outputDll))
+        if ($NoCache)
+        {
+            # Cache bypassed by -NoCache switch
+            $needsBuild = $true
+        }
+        elseif (-not $outputDll -or -not (Test-Path $outputDll))
         {
             # DLL doesn't exist, need to build
             $needsBuild = $true
@@ -91,28 +98,34 @@ if (-not $Interactive -or $BuildArgs)
         if ($needsBuild)
         {
             # Build is needed
-            Write-Host "Build cache invalid, rebuilding..." -ForegroundColor Cyan
+            Write-Host "Building Build$ProductName..." -ForegroundColor Cyan
             & dotnet build $projectPath
             if ($LASTEXITCODE -ne 0)
             {
                 throw "Build failed with exit code $LASTEXITCODE"
             }
 
+            # Re-find the output DLL after build
+            if (Test-Path $binDebugPath)
+            {
+                $outputDll = Get-ChildItem -Path $binDebugPath -Filter "Build$ProductName.dll" -Recurse -ErrorAction SilentlyContinue | Select-Object -First 1 | ForEach-Object { $_.FullName }
+            }
+
             # Update the DLL timestamp to mark the cache as valid
             if ($outputDll -and (Test-Path $outputDll))
             {
                 (Get-Item $outputDll).LastWriteTime = Get-Date
             }
+            else
+            {
+                throw "Build succeeded but output DLL '$outputDll' not found."
+            }
         }
-        else
-        {
-            Write-Host "Build cache valid, skipping build." -ForegroundColor Green
-        }
-
+      
         # Run the project using dotnet exec (faster than dotnet run)
         if (-not $outputDll -or -not (Test-Path $outputDll))
         {
-            throw "Output DLL not found at: $outputDll"
+            throw "Output DLL not found. Expected path: '$outputDll'."
         }
 
         & dotnet exec $outputDll $BuildArgs