[fpc-pascal] FpSonar - a pascal linter

[Michael Van Canneyt]

Sorry, I should have been more clear. This is part of fpc.

So it's in gitlab:

https://gitlab.com/freepascal.org/fpc/source/-/tree/main/utils/fpsonar

The code compiles with FPC 3.2.2, though, I made sure of that. 
I'll see about making a zip with just the fcl-passrc/sonar units, and report back.

Michael.

On Thu, 9 Jul 2026, Tim Coates via fpc-pascal wrote:

> Hi Michael,
>
> Link please? I'd love to try it out.
>
> Tim
>
> On Thu, 9 July 2026, 6:22 am Michael Van Canneyt via fpc-pascal, <
> fpc-pascal at lists.freepascal.org> wrote:
>
>>
>> Hi,
>>
>> I've finished something I have been brooding on for some months now:
>>
>> FPSonar - a Object Pascal linter, written in Object Pascal
>>
>> What does it do?
>>
>> It has roughly 140-150 rules on how pascal code should be written to be
>> readable. It parses your code (using fcl-passrc) and will check all these
>> rules. It will then generate a report.
>>
>> Examples of checks:
>>
>> RoutineTooLarge - too long routines are flagged.
>>
>> TooManyParameters - Procedure takes too many parameters.
>>
>> TooManyNestedRoutines - too many local nested routines.
>>
>> RemoveUnusedConstant - there is a constant that is never used.
>>
>> FileNotTooManyClasses - too many classes in a file.
>>
>> FormatArgumentType - wrong type for Format() argument.
>>
>> LowercaseKeywords - keywords should be lowercase.
>>
>> Some of these the compiler will flag (or the IDE code observer),
>> but most are not. There are many of them.
>>
>> You can configure these checks (how long is too long, what is too many
>> parameters etc.) or disable checks altogether. The configuration file is a
>> JSON file.
>>
>> You can also mark a line in code so it will not be checked:
>>   SomeCommand; // NOSONAR
>> The NOSONAR comment will suppress any warnings about that line.
>>
>> The basic rule is: if the linter cannot determine with certainty that
>> something is wrong, it will not report it. For example, if it cannot with
>> certainty determine the type of a format argument, then no error/warning
>> will be reported about a type mismatch.
>>
>> In order to do its job properly, it sometimes needs to know what the FPC
>> units
>> contain, and it automatically runs FPC's ppudump tool to find out - so it
>> does not need to parse the FPC code (although it can also do the latter).
>> In case you don't want that, you can let it simply use some built-in basic
>> copies of some essential FPC units (system, sysutils, classes).
>>
>> To start using this tool on an old codebase can prove daunting - you can
>> start out with many 1000's of 'errors'. In order to help with that you can
>> make a baseline, a snapshot which you can compare against in subsequent
>> runs
>> so you at least don't make things worse. This gives you time to slowly fix
>> the existing issues while ensuring you don't add new ones.
>>
>> I'm still working on a Lazarus IDE plugin.
>>
>> In case you were wondering about the name: it's a reference to SonarQube,
>> a Java tool which does something similar (even for Pascal),
>> but is 1000 times harder to use than fpSonar.
>>
>> If you find you're missing checks or have ideas for additional checks,
>> feel free to contact me. if they can be implemented, I will look at it.
>>
>> Enjoy,
>>
>> Michael.
>> _______________________________________________
>> fpc-pascal maillist  -  fpc-pascal at lists.freepascal.org
>> https://lists.freepascal.org/cgi-bin/mailman/listinfo/fpc-pascal
>>
>