I removed fixtures from the PR, as I used them during the development but are not required by uniquetargets_test.go. They could be used to test CLI in cmd/checkmake/main_test.go but may be overkill.

$ make clean && make binaries
$ ./checkmake list-rules
       NAME                    DESCRIPTION            
 maxbodylength      Target bodies should be kept      
                    simple and short (no more than 8  
                    lines).                           
 minphony           Minimum required phony targets    
                    must be present (all,clean,test). 
 phonydeclared      Every target without a body needs 
                    to be marked PHONY                
 timestampexpanded  timestamp variables should be     
                    simply expanded                   
 uniquetargets      Targets should be uniquely        <-- the new rule
                    defined; duplicates can cause     
                    recipe overrides or unintended    
                    merges.                           

What would be missing to document the rule somewhere, but I think that's missing for all rules.

@mikelolasagasti wrote:

What would be missing to document the rule somewhere, but I think that's missing for all rules.

yes. I think we should add rule descriptions to the manpage:
https://github.com/checkmake/checkmake/blob/main/man/man1/checkmake.1.md

Maybe even add a new section for rules to the manpage.
The latter should be a separate PR though.

@mikelolasagasti wrote:

I removed fixtures from the PR, as I used them during the development but are not required by uniquetargets_test.go.

Sounds good.

They could be used to test CLI in cmd/checkmake/main_test.go but may be overkill.

Agreed. The go test file is meant to hold unit tests, not end-to-end CLI tests.