Add VariablePlaceholder suggestion

Author: homebysix

CHANGELOG.md

@@ -20,6 +20,7 @@ All notable changes to this project will be documented in this file. This projec
 
 - Include `SignToolVerifier` and `URLDownloaderPython` AutoPkg processors when suggesting minimum versions.
 - Updated AutoPkg recipe type convention checking to include new `JamfUpload` processors as well as `URLDownloaderPython` and `MunkiInfoCreator`.
+- Added a suggestion to use Rich Trouton's [VariablePlaceholder](https://derflounder.wordpress.com/2024/08/16/setting-custom-variables-in-autopkg-using-the-variableplaceholder-processor/) processor for setting arbitrary environment variables instead of supplying unexpected arguments to existing processors.
 
 ### Fixed
 

pre_commit_hooks/check_autopkg_recipes.py

@@ -521,17 +521,23 @@ def validate_proc_args(process, filename):
                 # Skip args in ignored list above.
                 continue
 
+            suggestion = (
+                "Consider using the VariablePlaceholder processor for adding custom environment variables:\n"
+                "https://derflounder.wordpress.com/2024/08/16/setting-custom-variables-in-autopkg-using-the-variableplaceholder-processor/"
+            )
             if not core_procs[proc["Processor"]]:
                 print(
                     f"{filename}: Unknown argument {arg} for processor {proc['Processor']}, "
                     "which does not accept any arguments."
                 )
+                print(suggestion)
                 passed = False
             elif arg not in core_procs[proc["Processor"]]:
                 print(
                     f"{filename}: Unknown argument {arg} for processor {proc['Processor']}. Allowed arguments are: "
                     + ", ".join(core_procs[proc["Processor"]])
                 )
+                print(suggestion)
                 passed = False
 
     return passed