Whilst debugging a problem in dovecot LDA over the last few days, I came across two different issues in coding techniques.

(Note: Please don't take this negatively; my intent is both positive and constructive!)

The front page of the website www.dovecot.org says: "it uses several coding techniques to avoid most of the common pitfalls"

So I hope it is OK to follow the spirit of that with some suggestions.

The two issues I encountered both seem to be fairly easy holes to fall into, and yet equally easy to avoid in the first place by using established C practices.

Firstly, many 'if' statements having a single statement (whether in then or else part) are currently written in a short-cut fashion:

if (condition) statement 1; else statement 2;

This, though technically legal, is potentially lethal when inserting (say) debugging statements. Without diligence it is all to easy to produce:

if (condition) debug 1a; statement 1; debug 1b; else debug 2a; statement 2; debug 2b;

A simple edit that looks, layout-wise, as if it would do the right thing (and do in Python!); but actually radically changes the execution flow. (This is left as an exercise to the reader... to demonstrate the point.)

Could I suggest that the relevant brackets be always used as a matter of course? Something like:

if (condition) { statement 1; } else { statement 2; }

Then the insertion of debug statements doesn't inflict surprise.

(No, I didn't fall into this hole. But it is a trap waiting to happen.)

Secondly, code duplication. To give one example: 'get_var_expand_table()' appears in both 'deliver/deliver.c' and 'master/mail-process.c'. (There is also a similar looking function in 'auth/auth-request.c'.) Perhaps consideration should be given to merging such instances. For instance, my woes with "%i"-expansion being treated differently in mail-reading and mail-delivery would likely never have arisen if common code had been used.

I hope that helps (constructively!).

Best wishes.

--

: David Lee I.T. Service : : Senior Systems Programmer Computer Centre : : Durham University : : http://www.dur.ac.uk/t.d.lee/ South Road : : Durham DH1 3LE : : Phone: +44 191 334 2752 U.K. :