[Bug c++/95763] New: Feature request: compiler warning if line width exceeds N symbols

[Bug c++/95763] New: Feature request: compiler warning if line width exceeds N symbols

[hyena at hyena dot net.ee]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95763

            Bug ID: 95763
           Summary: Feature request: compiler warning if line width
                    exceeds N symbols
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Keywords: diagnostic, easyhack
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: hyena at hyena dot net.ee
  Target Milestone: ---

Actually, this is a feature request, not a bug report.

It would be very useful if I could specify in a source file the maximum number
of symbols per line that the source file is allowed to contain. If some line
exceeds that limit, then the compiler should print the respective warning
mentioning the line number where the limit is exceeded.

[Bug c++/95763] Feature request: compiler warning if line width exceeds N symbols

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95763

--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> ---
This seems like a better fit for something like clang-tidy than being hardcoded
into the compiler.

[Bug c++/95763] Feature request: compiler warning if line width exceeds N symbols

[hyena at hyena dot net.ee]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95763

--- Comment #2 from Erich Erstu <hyena at hyena dot net.ee> ---
(In reply to Jonathan Wakely from comment #1)
> This seems like a better fit for something like clang-tidy than being
> hardcoded into the compiler.

I can see the reasoning there, but different source/header files may have
different maximum line width limitations. For example, we may have a project
where most files are limited to 80 symbols per line but a subset of header
files is limited to 240 symbols per line (as an exception). So, this could not
be handled as a project-wide restriction but rather case-by-case. For example,
those header files may contain large multidimensional nested arrays/tables
(basically data) which requires an exception to be made.

For the above reasons, it would make sense to keep the line width limit as part
of the code file that is supposed to respect that limit. Clang-tidy would have
to get these limits from an external configuration file which bloats the
project. Since GCC already implements special comments such as "// fall
through" for switch statements, I could see this implemented similarly, as a
comment in the beginning of the code file.

[Bug c++/95763] Feature request: compiler warning if line width exceeds N symbols

[joseph at codesourcery dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95763

--- Comment #3 from joseph at codesourcery dot com <joseph at codesourcery dot com> ---
FWIW, the Ada front end has some style checking support (I once broke 
bootstrap by applying spelling corrections there, where fixing the 
spelling in a comment made a line too long).  It wouldn't be ridiculous to 
have such checks available for C and C++, so far as formatting checks work 
reasonably in the presence of macros.

[Bug c++/95763] Feature request: compiler warning if line width exceeds N symbols

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95763

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jakub at gcc dot gnu.org

--- Comment #4 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
The fortran FE also has diagnostics about source line lengths.
The question is e.g. if comments should be an exception or not.

[Bug c++/95763] Feature request: compiler warning if line width exceeds N symbols

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95763

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
           Severity|normal                      |enhancement
   Last reconfirmed|                            |2021-04-17
     Ever confirmed|0                           |1

--- Comment #5 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
I assume you are talking about stuff like:
int t, t1, t2, t43, t55, t6, t7888888, t99999, t999876, t323434, ttsdgsdg,
thfgd, tdfhghh, t354635463546;

?
If so confirmed. I have not looked into how to do this and if this is normally
not useful without a code style checker.

Having a code style checker part of GCC would be a good long term really.