[cfe-dev] scan-build "No bugs found."

[Artem Dergachev via cfe-dev]

You can hard-confirm if the analyzer is running by seeing if you have 
any "clang -cc1 -analyze ..." processes during analysis. Though, those 
"ANALYZE (Syntax)" lines are definitely from the analyzer.

The scan-build tool has known issues, which you might have stepped into.

It might be that all warnings you're seeing in the console are 
"cross-file" (eg. some part of the path in header and some in the main 
file), which is **very unfortunately** not supported by the html 
diagnostic output (which produces one plain-html file per warning, 
incorporating a single file through the HTMLRewrite mechanism), so such 
warnings would be dropped by scan-build but appear in console.

The other option is to use scan-build -plist, which would not drop 
warnings but produce barely readable XML output; normally, plists are 
for use by IDEs that try to integrate the analyzer (like Xcode and 
QtCreator; i don't think they use scan-build internally though, as they 
don't need an external compiler interceptor to understand their build 
system anyway).

So unless somebody implements a proper multi-file html report output, 
we're either stuck with these few IDEs or miss some warnings (normally 
not too many).

I tried to reproduce the issue and it *seems* (but i didn't dig deeper) 
that some of them are cross-file (note that when the whole report is 
inside a header, it's not a problem).

 > Also, although I redirect both stdout and stderr, the lines I 
mentioned -- "ANALYZE ..." and "1 warning generated." -- are nonetheless 
printed on the console, not [1]. Why is that?

The scan-build script messes up stdout and stderr dramatically to 
produce reasonable output at least to console, tackling with mutliple 
sources from multiple processes (original compiler and ccc-analyzer 
instances) and piping their stdout and stderr around. I didn't dare to 
understand this ever, but i agree it's not quite UNIX-way.


On 1/18/17 1:39 AM, Jack Bates via cfe-dev wrote:
> I'm running scan-build on Apache Traffic Server and getting "No bugs 
> found.", which isn't what I expect.
>
> I ran it as follows:
>
>   $ git clone https://github.com/apache/trafficserver.git
>   $ cd trafficserver
>   $ autoreconf -i
>   $ ./configure
>   $ scan-build -v -v make V=1 2>&1 > ~/Desktop/scan-build
>
> Here's the output [1].
>
> I didn't run ./configure through scan-build, but I conclude from the 
> Make output that the compiler is being correctly interposed upon, so I 
> shouldn't need to? The output indicates that the compiler is 
> c++-analyzer.
>
> The output contains lines like the following, so I conclude that the 
> analyzer is working?
>
>   ANALYZE (Syntax): ../../lib/ts/ink_mutex.h ~x_pthread_mutexattr_t
>
> And it contains lines like "1 warning generated.", so I conclude that 
> there should be bugs?
>
> So my first question is, why are there "No bugs found."?
>
> Also, although I redirect both stdout and stderr, the lines I 
> mentioned -- "ANALYZE ..." and "1 warning generated." -- are 
> nonetheless printed on the console, not [1]. Why is that?
>
> Thanks!
>
> [1] http://nottheoilrig.com/scan-build
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