do professional PHP programmers use error checking in their code?

[B.r.K.o.N.j.A]

Re: do professional PHP programmers use error checking in their code?

My own feeling, obviously, is that it is better to error check

everything, and to write extensive comments everywhere. I've taken over
PHP projects, started by other programmers, that had no error checking
and no comments, and such projects are always a big pain in the neck. I
lose time playing Sherlock Holmes, trying to track down where a
function's parameter first originates and why it's in use. I'd rather
have a comment on it, and error message for when the wrong thing is
passed in. Obviously this slows development. Is there any concensus
among developers about what is the best approach? I think whatever is
cheapest for the client should be considered the best approach, but it
seems to me cheapest-in-the-short-term is quite different from
cheapest-in-the-long-term.

In my personal opinion and experience, if I were a project manager and
I've heard the words "php will handle errors for you, why bother?" from
any of the programmers I work with, I would fire that person on spot.
It's HORRIBLE practice and it leads to lots of crap php code out there
and also the "not serious programmer" stereotype about php developers
(enforced mostly by java and c# folks - who (you've guessed it :) handle
their errors and exceptions). So my advice is handle all the errors, USE
the exceptions as much as you can, log errors for after analysis but
don't reinvent the wheel (e.g. don't reinvent the text of DB error
messages, just handle them and give them context).

--

B.r.K.o.N.j.A = Bionic Robotic Knight Optimized for Nocturnal Judo and
Assasination

[Chung Leong]

Re: do professional PHP programmers use error checking in their code?

Peter Fox wrote:

* Distinguish between
- Errors and exceptions (Exceptions are where something doesn't work
as normal. Errors are where an incorrect result/action is obtained.)

Making that distinction is important. That's where the colleague of the
OP erred. Error handling/reporting in PHP is different not because it's
a scripting language. It's different because it's designed for web
application. Unlike desktop apps, the operating environment for web
apps is usually controlled by the programmer. That allows PHP to make
the assumption that any error encountered is a programming error and
accordingly, throwing up a message to inform the programmer. Take
fopen() for instance. In a desktop app it could fail in normal
circumstances (end-user mistake etc.) In a PHP app, when it fails it
usually means the programmer did something wrong, as the file being
opened can either be a file that's part of the app or a file uploaded.
The guy is correct is saying that it's pointless to do what PHP does
for you already.

For example if (in the UK) I ask for a date then I want it in
day-month-year order. But you might be used to m-d-y and input to my
form like that.

That's not a terribly good example, I must say. User errors should
always be expected. Handling them is part of a application's basic
functionality.

What does the function getRow() return? Here I'll assume it is an alias
for mysql_fetch_arr ay() which returns FALSE if there's a problem. So if
the result is to be tested it is good practice to test according to the
signals in the documentation.
if(FALSE===getR ow($result)){

I didn't mention it since it's just an example, but there is really no
way for that condition to arise. If mysql_num_rows( ) succeeds, then
mysql_fetch_arr ay() cannot fail, since the rows are in memory already.

So spend less time on fancyfying the bits that you think might go wrong
and more on discovering what the important failure modes are; and
understanding the context in which the information is going to be used.

The only real failure modes are (a) the DB connection is bad, or (b)
the table weblogs is missing or don't have the right column names.
PHP's error reporting mechanism would inform you of both. If one wants
to be helpful, then say something that's actually informative like "the
database schema is incorrect, run create_tables.p hp to create the
database." Otherwise, if all you're writing are messages in the vein of
"an error happened," then you might as well leave it to PHP.