Filter out AnalysisErrors with null 'errorCode'.

Filter out AnalysisErrors with null 'errorCode'.

We have an error report:


My guess is that `errorCodeByUniqueName` returned `null`.

It might be either a bug in `errorCodeByUniqueName`, or a shortcoming
or our current data version mechanism (which we know about - it should
be a hash of sources or something like this).

Either way, a missing error is better than a crash.

R=paulberry@google.com, brianwilkerson@google.com
BUG=

Committed: https://github.com/dart-lang/sdk/commit/5ff8db3a5f75b699ead93a9ffdb8998b9608c505

[Paul Berry, 2016-11-26 15:19:39]

I'm concerned because the only explanation I can think of for this error
occurring is that the user ran a version of analysis server in which a certain
error code existed, and then ran another version of analysis server in which
that error code no longer existed.  That seems really unlikely, since the new
analysis driver hasn't been around very long, and the last time we removed an
error code was November 4 (68f290c9d84da8bef8381452d2a9f42a0a646234).

I think we should get more information before introducing code that covers up
the problem, especially since the new analysis driver hasn't been enabled by
default yet so we can do so without inconveniencing too many users.  How about
if, for example, we change the code so that it throws an exception which
contains the problematic value of error.uniqueName in its message?  Or maybe
contains the pathname of the file containing the corrupted data, so that we can
inspect the file?

I would be ok making this change at a later date, if this error keeps occurring
and we can't figure out why.

[scheglov, 2016-11-27 18:13:18]

PTAL

[Paul Berry, 2016-11-27 23:17:19]

lgtm

[scheglov, 2016-11-28 16:43:23]

Description was changed from

==========
Filter out AnalysisErrors with null 'errorCode'.

We have an error report:


My guess is that `errorCodeByUniqueName` returned `null`.

It might be either a bug in `errorCodeByUniqueName`, or a shortcoming
or our current data version mechanism (which we know about - it should
be a hash of sources or something like this).

Either way, a missing error is better than a crash.

R=brianwilkerson@google.com, paulberry@google.com
BUG=
==========

to

==========
Filter out AnalysisErrors with null 'errorCode'.

We have an error report:


My guess is that `errorCodeByUniqueName` returned `null`.

It might be either a bug in `errorCodeByUniqueName`, or a shortcoming
or our current data version mechanism (which we know about - it should
be a hash of sources or something like this).

Either way, a missing error is better than a crash.

R=paulberry@google.com, brianwilkerson@google.com
BUG=

Committed:
https://github.com/dart-lang/sdk/commit/5ff8db3a5f75b699ead93a9ffdb8998b9608c505
==========

[scheglov, 2016-11-28 16:43:25]

Committed patchset #2 (id:20001) manually as
5ff8db3a5f75b699ead93a9ffdb8998b9608c505 (presubmit successful).

[Brian Wilkerson, 2016-11-28 18:20:39]

lgtm