Warn people not to enable xdebug.show_exception_trace

Stupid question but are you sure that database has the relevant permissions? You say nothing about setting up the db in your post. Just an idea. I have seen (with D6) similar errors when permissions were wrong/incomplete.

Are you sure that PDO is not installed from PECL?
Looks like it...

You are of course welcome.

I'm setting this back to active; because this error happens quite late, we should be able (I guess) to check whether xdebug.show_exception_trace is on during the requirements check.

Please test; I'm not in the possession of an xdebug install atm.

I tested on an install with xdebug and it does produce a requirements error when the setting is enabled.

I don't see a Drupal bug here. If you ask for trace, you get a trace. It isn't our fault that it happens for caught exceptions. File a bug with xdebug, no?

There is no bug, not in xdebug, not in Drupal.

The setting prevents installation though, and while not all the rage, seems not to be uncommon on potential Drupal developer's local instances. Afaik this is the third or fourth report.

One more report, and yes, #12 works.

I guess shunting means #15. Can somebody confirm that?

Hm. I'm a bit torn on this one. I don't like putting code into core that checks specific developer tools' configurations. It becomes a "me too" game and pretty soon we end up with vi tab set lines in all of our code files.

OTOH, this is an installer bug, and to those who hit it Drupal will seem extremely broken indeed.

Gonna let this sit for another couple days and thinker a bit more.

I do mean #12.

Ok, I have thought this over, and in the end I think we don't want to start including specific checks for specific environment variables in the installer. There's still a couple of days if people strongly disagree.

What I have done instead is my best to encapsulate #12 into the system requirements page (diff) since that does get into all those nitty-gritty configuration details and can be added to/updated at any time (not bound to string freeze).

Reopening this issue as per catch's comment in #1074098: DatabaseConnectionNotDefinedException: The specified database connection is not defined: default.

This was fixed via the requirements page.

Could someone clarify why this setting causes the Drupal installer to stop working? I get why it's printing the stack trace to the screen, of course, but I'm not sure I understand why that prevents Drupal from being installed. It seems there could be a bug.

Either way, I think we can do something within Drupal to address this. It shouldn't be necessary to add code that checks for xdebug-specific settings. At the very least, couldn't we just do something like this earlier in the installation process?

try {
  throw new Exception('Your server is not configured to handle exceptions properly.  See the [system requirements page on d.o.] for more information.');
}
catch (Exception $e) {
}

Not very pretty looking, of course, but at least it would give people who run into this a clear message that explains what the problem is.

That won't work. Xdebug will display traces no matter if an exception was caught (source).

// Edit: my bad. I just read the code and not the exception's message...

@Xano, yes, that's the idea. The point is that if we can't stop it from showing the exception trace, at least we can make the exception message itself something meaningful for the situation (rather than "PDOException: SQLSTATE[42S02]: Base table or view not found: 1146 Table 'd7dev.variable' doesn't exist" like the situation that started this thread, or whatever other random exception might happen to trigger it).