Catch file-not-found exception

Catch file-not-found exception

If a non-existing file was passed to DDC before it would just throw an
uncaught exception and crash. Now the exception is caught and an error
message is printed together with the usage information.

BUG=https://github.com/dart-lang/dev_compiler/issues/605
R=jmesserly@google.com

Committed: https://github.com/dart-lang/dev_compiler/commit/19a2340eebab18fd2a851da04f8e4f33e730a113

[stanm, 2016-07-18 17:43:59]

stanm@google.com changed reviewers:
+ jmesserly@google.com

[stanm, 2016-07-18 17:44:00]

I'm not sure this is the best way to handle this. I tried adding a try/catch in
code_generator.dart and propagating the message via the errors list, but it
seems that it contains AnalysisError objects, which don't seem appropriate for a
FileDNE error.

Also, it would be nice to print which file does not exist, but the best way of
doing that was to parse the exception message, which doesn't seem like the best
engineering practice.

Suggestions would be very welcome!

[Jennifer Messerly, 2016-07-18 17:50:33]

LGTM!

[stanm, 2016-07-18 18:51:23]

I'm happy with the second patch set. PTAL

[Jennifer Messerly, 2016-07-18 19:22:01]

LGTM

https://codereview.chromium.org/2161693002/diff/20001/lib/src/compiler/compil...
File lib/src/compiler/compiler.dart (right):

https://codereview.chromium.org/2161693002/diff/20001/lib/src/compiler/compil...
lib/src/compiler/compiler.dart:82: throw new AnalysisException('could not create
a source for $sourcePath.'
do you mind fixing this one too?

throw new UsageException

https://codereview.chromium.org/2161693002/diff/20001/lib/src/compiler/compil...
lib/src/compiler/compiler.dart:88: 'You need to pass at least one existing .dart
file as an argument.');
long line

[stanm, 2016-07-18 21:37:29]

Implemented changes.

https://codereview.chromium.org/2161693002/diff/20001/lib/src/compiler/compil...
File lib/src/compiler/compiler.dart (right):

https://codereview.chromium.org/2161693002/diff/20001/lib/src/compiler/compil...
lib/src/compiler/compiler.dart:82: throw new AnalysisException('could not create
a source for $sourcePath.'
On 2016/07/18 19:22:01, John Messerly wrote:
> do you mind fixing this one too?
> 
> throw new UsageException

Done.

https://codereview.chromium.org/2161693002/diff/20001/lib/src/compiler/compil...
lib/src/compiler/compiler.dart:88: 'You need to pass at least one existing .dart
file as an argument.');
On 2016/07/18 19:22:01, John Messerly wrote:
> long line

Thanks, I noticed that, but the formatter seems to be unable to deal with it, so
I didn't fix it immediately. I'll fix it now.

[stanm, 2016-07-18 21:37:51]

Description was changed from

==========
Catch file-not-found exception

If a non-existing file was passed to DDC before it would just throw an
uncaught exception and crash. Now the exception is caught and an error
message is printed together with the usage information.

BUG=https://github.com/dart-lang/dev_compiler/issues/605
==========

to

==========
Catch file-not-found exception

If a non-existing file was passed to DDC before it would just throw an
uncaught exception and crash. Now the exception is caught and an error
message is printed together with the usage information.

BUG=https://github.com/dart-lang/dev_compiler/issues/605
R=jmesserly@google.com

Committed:
https://github.com/dart-lang/dev_compiler/commit/19a2340eebab18fd2a851da04f8e...
==========

[stanm, 2016-07-18 21:37:52]

Committed patchset #3 (id:40001) manually as
19a2340eebab18fd2a851da04f8e4f33e730a113 (presubmit successful).