Re: [PATCH v2] checkpatch: Add a warning for log messages that don't end in a new line

From: Julia Lawall
Date: Mon Nov 27 2017 - 01:08:38 EST




On Sun, 26 Nov 2017, Joe Perches wrote:

> On Sun, 2017-11-26 at 23:44 +0100, Julia Lawall wrote:
> > My semantic patch and results are below. The semantic patch has some
> > features that may or may not be desired:
> >
> > 1. It goes beyond printk, pr_xxx, dev_xxx, and netdev_xxx, by finding
> > functions that are sometimes used with a format string ending with a
> > newline. To reduce false positives, such a function is ignored if it is
> > sometimes used with a string that ends in a space. This could lead to
> > false positives where actually one of the calls has a \n that it should
> > not have.
> >
> > 2. Coccinelle puts multipart strings on a single line. So the rule goes
> > a little further and eliminates the multipartness. Basically "xxx " "yyy"
> > becomes "xxx yyy" regardless of the length of the result.
>
> What about the semi-common string concatenation "foo" #var "bar" ?

I don't think this is an issue. There is no " " pattern in this. It's
true that if the pieces were on separate lines, Coccinelle will now put
them on a single line. I'm not sure I want to bother with this.

> > 3. Some prints appear not to end with a newline because they end with \n.
> > where .\n was likely intended. Instead of creating \n.\n, the semantic
> > patch just moves the .to the left of the . And if there was .\n. it just
> > drops the final period.
>
> That may be a problem if the sentence is "something...\n"

I think I was not clear. The sentence ends in ".\n.".

> There seem to be many false positives in here too.

Could you point to something specifically? I saw a lot of cases with
prints followed by returns and gotos. I guess those are not likely false
positives.

julia