[Python-Dev] Update PEP 7 to require curly braces in C (original) (raw)

David Malcolm dmalcolm at redhat.com
Tue Jan 19 10:36:56 EST 2016

On Mon, 2016-01-18 at 19:18 -0500, Terry Reedy wrote:

On 1/18/2016 6:20 PM, Brett Cannon wrote: > > > On Sun, 17 Jan 2016 at 11:10 Brett Cannon <brett at python.org_ _> <mailto:brett at python.org>> wrote: > > While doing a review of http://bugs.python.org/review/26129/ I asked > to have curly braces put around all if statement bodies. Serhiy > pointed out that PEP 7 says curly braces are optional: > https://www.python.org/dev/peps/pep-0007/#id5. I would like to > change that. > > My argument is to require them to prevent bugs like the one Apple > made with OpenSSL about two years ago: > https://www.imperialviolet.org/2014/02/22/applebug.html. Skipping > the curly braces is purely an aesthetic thing while leaving them out > can lead to actual bugs. > > Anyone object if I update PEP 7 to remove the optionality of curly > braces in PEP 7? > > > Currently this thread stands at: > > +1 > Brett > Ethan > Robert > Georg > Nick > Maciej Szulik > +0 > Guido > -0 > Serhiy > MAL > -1 > Victor (maybe; didn't specifically vote) > Larry > Stefan

Though I don't write C anymore, I occasionally read our C sources. I dislike mixed bracketing in a multiple clause if/else statement, and would strongly recommend against that. On the other hand, to my Python-trained eye, brackets for one line clauses are just noise. +-0. If coverity's scan does not flag the sort of misleading bug bait formatting that at least partly prompted this thread if (a): b; c; then I think we should find or write something that does and run it over existing code as well as patches.

FWIW, for the forthcoming gcc 6, I've implemented a new -Wmisleading-indentation warning that catches this. It's currently enabled by -Wall:

sslKeyExchange.c: In function 'SSLVerifySignedServerKeyExchange': sslKeyExchange.c:631:8: warning: statement is indented as if it were guarded by... [-Wmisleading-indentation] goto fail; ^~~~ sslKeyExchange.c:629:4: note: ...this 'if' clause, but it is not if ((err = SSLHashSHA1.update(&hashCtx, &signedParams)) != 0) ^~

(not that I've had time for core Python development lately, but FWIW in gcc-python-plugin I mandate braces for single-statement clauses).

Dave

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