Add ability to set compiler defines (#10)

For Ticket #9
All 38 tests pass

Author: darianmiller

CHANGELOG.md

@@ -3,6 +3,10 @@
 All notable changes to this project will be documented in this file.
 
 ---
+## [0.3.0] - Unreleased
+
+- Add support for passing compiler defines to MSBUILD
+[#9](https://github.com/continuous-delphi/delphi-msbuild/issues/9)
 
 ## [0.2.0] - 2026-03-16
 

README.md

@@ -115,6 +115,42 @@ The MSBuild verbosity level.  Passed to MSBuild as `/v:<value>`.
 
 Valid values: `quiet`, `minimal`, `normal`, `detailed`, `diagnostic`
 
+## -Define
+
+```text
+-Define <string[]>
+```
+
+One or more additional MSBuild defines to pass to the compiler.  When at least
+one value is supplied, the script appends the following to the MSBuild command
+line:
+
+```text
+/p:DCC_Define="$(DCC_Define);DEFINE1;DEFINE2"
+```
+
+The `$(DCC_Define)` prefix preserves the defines already set by the project's
+PropertyGroups (e.g. `DEBUG`, `RELEASE`).  Without it, the property assignment
+would replace them entirely.
+
+When no `-Define` values are supplied (the default), the `/p:DCC_Define`
+argument is omitted entirely.
+
+Examples:
+
+```powershell
+# Single define
+delphi-msbuild.ps1 -ProjectFile .\src\MyApp.dproj -RootDir $root -Define CI
+
+# Multiple defines
+delphi-msbuild.ps1 -ProjectFile .\src\MyApp.dproj -RootDir $root `
+    -Define MYFLAG, USE_JEDI_JCL
+
+# Via pipeline with defines
+delphi-inspect.ps1 -DetectLatest -Platform Win32 -BuildSystem MSBuild |
+    delphi-msbuild.ps1 -ProjectFile .\src\MyApp.dproj -Define CI, MYFLAG
+```
+
 ## -ShowOutput   (switch)
 
 ```text

source/delphi-msbuild.ps1

@@ -74,6 +74,8 @@ param(
   [ValidateSet('quiet','minimal','normal','detailed','diagnostic')]
   [string]$Verbosity = 'normal',
 
+  [string[]]$Define = @(),
+
   [switch]$ShowOutput
 )
 
@@ -177,6 +179,7 @@ function Invoke-MsbuildProject {
     [string]$Config,
     [string]$Target,
     [string]$Verbosity,
+    [string[]]$Define = @(),
     [switch]$ShowOutput
   )
 
@@ -188,6 +191,11 @@ function Invoke-MsbuildProject {
     "/v:$Verbosity"
   )
 
+  if ($Define.Count -gt 0) {
+    $defineValue = '$(DCC_Define);' + ($Define -join ';')
+    $msbuildArgs += "/p:DCC_Define=$defineValue"
+  }
+
   return Invoke-MsbuildExe -Arguments $msbuildArgs -ShowOutput:$ShowOutput
 }
 
@@ -236,6 +244,7 @@ try {
     -Config       $Config `
     -Target       $Target `
     -Verbosity    $Verbosity `
+    -Define       $Define `
     -ShowOutput:$ShowOutput
 
   $resultObj = [pscustomobject]@{

tests/pwsh/delphi-msbuild.Tests.ps1

@@ -26,6 +26,9 @@
     Passes correct MSBuild arguments to Invoke-MsbuildExe.
     Forwards -ShowOutput switch to Invoke-MsbuildExe.
     Returns the result object from Invoke-MsbuildExe.
+    Omits /p:DCC_Define when no defines are supplied.
+    Appends /p:DCC_Define with $(DCC_Define) prefix for a single define.
+    Appends /p:DCC_Define with $(DCC_Define) prefix for multiple defines.
 
   Describe 5 - Main flow (via Invoke-ToolProcess, no MSBuild calls):
     Exits 3 when no rootDir is provided (no pipeline, no -RootDir).
@@ -293,6 +296,78 @@ Describe 'Invoke-MsbuildProject' {
 
   }
 
+  Context 'omits /p:DCC_Define when no -Define values are supplied' {
+
+    BeforeAll {
+      $script:capturedArgs = $null
+      Mock Invoke-MsbuildExe {
+        $script:capturedArgs = $Arguments
+        return [pscustomobject]@{ ExitCode = 0; Output = '' }
+      }
+
+      Invoke-MsbuildProject `
+        -ProjectFile 'C:\Projects\MyApp.dproj' `
+        -Platform    'Win32' `
+        -Config      'Debug' `
+        -Target      'Build' `
+        -Verbosity   'normal'
+    }
+
+    It 'does not include any /p:DCC_Define argument' {
+      $script:capturedArgs | Should -Not -Contain { $_ -like '/p:DCC_Define=*' }
+      ($script:capturedArgs | Where-Object { $_ -like '/p:DCC_Define=*' }) | Should -BeNullOrEmpty
+    }
+
+  }
+
+  Context 'appends /p:DCC_Define with $(DCC_Define) prefix for a single define' {
+
+    BeforeAll {
+      $script:capturedArgs = $null
+      Mock Invoke-MsbuildExe {
+        $script:capturedArgs = $Arguments
+        return [pscustomobject]@{ ExitCode = 0; Output = '' }
+      }
+
+      Invoke-MsbuildProject `
+        -ProjectFile 'C:\Projects\MyApp.dproj' `
+        -Platform    'Win32' `
+        -Config      'Debug' `
+        -Target      'Build' `
+        -Verbosity   'normal' `
+        -Define      @('MYFLAG')
+    }
+
+    It 'includes /p:DCC_Define=$(DCC_Define);MYFLAG' {
+      $script:capturedArgs | Should -Contain '/p:DCC_Define=$(DCC_Define);MYFLAG'
+    }
+
+  }
+
+  Context 'appends /p:DCC_Define with $(DCC_Define) prefix for multiple defines' {
+
+    BeforeAll {
+      $script:capturedArgs = $null
+      Mock Invoke-MsbuildExe {
+        $script:capturedArgs = $Arguments
+        return [pscustomobject]@{ ExitCode = 0; Output = '' }
+      }
+
+      Invoke-MsbuildProject `
+        -ProjectFile 'C:\Projects\MyApp.dproj' `
+        -Platform    'Win32' `
+        -Config      'Debug' `
+        -Target      'Build' `
+        -Verbosity   'normal' `
+        -Define      @('MYFLAG', 'USE_JEDI_JCL')
+    }
+
+    It 'includes /p:DCC_Define=$(DCC_Define);MYFLAG;USE_JEDI_JCL' {
+      $script:capturedArgs | Should -Contain '/p:DCC_Define=$(DCC_Define);MYFLAG;USE_JEDI_JCL'
+    }
+
+  }
+
 }
 
 Describe 'Main flow -- pre-MSBuild validation (no MSBuild invoked)' {