[PATCH] libcamera: base: log: Fix uninitialized variable warning

[Laurent Pinchart]

On Mon, Mar 03, 2025 at 11:41:58AM +0100, Barnabás Pőcze wrote:
> 2025. március 2., vasárnap 3:09 keltezéssel, Laurent Pinchart írta:
> 
> > gcc 13.3.0, cross-compiling from amd64 to arm64, warns about a possibly
> > uninitialized variable in Logger::parseLogLevel():
> 
> Yet it has no problems with it when not cross compiling:
> https://gitlab.freedesktop.org/camera/libcamera/-/jobs/71959259 ...
> 
> > 
> > src/libcamera/base/log.cpp: In static member function ‘static libcamera::LogSeverity libcamera::Logger::parseLogLevel(std::string_view)’:
> > ../../src/libcamera/base/log.cpp:694:55: error: ‘severity’ may be used uninitialized [-Werror=maybe-uninitialized]
> >   694 |                 if (ec != std::errc() || *end != '\0' || severity > LogFatal)
> >       |                     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
> > src/libcamera/base/log.cpp:690:22: note: ‘severity’ was declared here
> >   690 |         unsigned int severity;
> >       |                      ^~~~~~~~
> > 
> > This appears to be a false positive, as the std::from_chars() function
> > should set severity value when it returns without an error. Still, the
> > warning is easy to solve, so fix it by initializing the severity
> > variable.
> 
> I am pretty sure it is false positive, barring any bugs in from_chars(), unfortunate...

I'm pretty sure as well, but I don't really see an alternative to this
patch for the time being.

> > Fixes: 8fa119e0b50f ("libcamera: base: log: Use `std::from_chars()`")
> > Signed-off-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> > ---
> >  src/libcamera/base/log.cpp | 3 +--
> >  1 file changed, 1 insertion(+), 2 deletions(-)
> > 
> > diff --git a/src/libcamera/base/log.cpp b/src/libcamera/base/log.cpp
> > index 6a040b59290a..8bf3e1daa9c6 100644
> > --- a/src/libcamera/base/log.cpp
> > +++ b/src/libcamera/base/log.cpp
> > @@ -687,14 +687,13 @@ LogSeverity Logger::parseLogLevel(std::string_view level)
> >  		"FATAL",
> >  	};
> > 
> > -	unsigned int severity;
> > +	unsigned int severity = LogInvalid;
> > 
> >  	if (std::isdigit(level[0])) {
> >  		auto [end, ec] = std::from_chars(level.data(), level.data() + level.size(), severity);
> >  		if (ec != std::errc() || *end != '\0' || severity > LogFatal)
> >  			severity = LogInvalid;
> >  	} else {
> > -		severity = LogInvalid;
> >  		for (unsigned int i = 0; i < std::size(names); ++i) {
> >  			if (names[i] == level) {
> >  				severity = i;
> > 
> > base-commit: c0a58b97989f7d529f1469b2c2f8705ff55d3af4

-- 
Regards,

Laurent Pinchart