Map merging.

Map merging.

Basic YAML map merging suitable for merging a default map with an overriding one.

The semantics favor the overrider with a twist to support a short-hand for lists that stand-in for maps of scalars to booleans.  Specifically, lint rules can be enumerated as a list or as a map.  To make this work, lists can be "promoted" to maps.  In particular, if

linter:
  rules:
    - camel_case_types
    - one_member_abstracts

is merged with

linter:
  rules:
    one_member_abstracts: false
    always_specify_return_types: true

the right thing is done to get us to:

linter:
  rules:
    camel_case_types: true
    one_member_abstracts: false
    always_specify_return_types: true

R=brianwilkerson@google.com, johnmccutchan@google.com

Committed: https://github.com/dart-lang/sdk/commit/67dc108f391937786a15c8adc17667486cf34548

[pquitslund, 2015-11-03 00:39:15]

pquitslund@google.com changed reviewers:
+ brianwilkerson@google.com, johnmccutchan@google.com

[Brian Wilkerson, 2015-11-03 01:07:27]

LGTM

https://codereview.chromium.org/1425393002/diff/1/pkg/analyzer/test/src/util/...
File pkg/analyzer/test/src/util/yaml_test.dart (right):

https://codereview.chromium.org/1425393002/diff/1/pkg/analyzer/test/src/util/...
pkg/analyzer/test/src/util/yaml_test.dart:29: }
Add a sibling to "three" to ensure that unmatched keys from both sides are
retained.

https://codereview.chromium.org/1425393002/diff/1/pkg/analyzer/test/src/util/...
pkg/analyzer/test/src/util/yaml_test.dart:35: 'nested': {'four': false, 'five':
true},
Can't actually tell whether the resulting value for "nested" is the result of a
merge or just the second value.

https://codereview.chromium.org/1425393002/diff/1/pkg/analyzer/test/src/util/...
pkg/analyzer/test/src/util/yaml_test.dart:61: });
Consider also testing
- merging maps and lists where the maps are not suitable for promotion, and
- merging two values that are neither maps nor lists.

[Cutch, 2015-11-03 15:00:02]

lgtm

[pquitslund, 2015-11-03 18:38:09]

Thank you!

https://codereview.chromium.org/1425393002/diff/1/pkg/analyzer/test/src/util/...
File pkg/analyzer/test/src/util/yaml_test.dart (right):

https://codereview.chromium.org/1425393002/diff/1/pkg/analyzer/test/src/util/...
pkg/analyzer/test/src/util/yaml_test.dart:29: }
On 2015/11/03 01:07:27, Brian Wilkerson wrote:
> Add a sibling to "three" to ensure that unmatched keys from both sides are
> retained.

Done.

https://codereview.chromium.org/1425393002/diff/1/pkg/analyzer/test/src/util/...
pkg/analyzer/test/src/util/yaml_test.dart:35: 'nested': {'four': false, 'five':
true},
On 2015/11/03 01:07:27, Brian Wilkerson wrote:
> Can't actually tell whether the resulting value for "nested" is the result of
a
> merge or just the second value.

Fixed.

https://codereview.chromium.org/1425393002/diff/1/pkg/analyzer/test/src/util/...
pkg/analyzer/test/src/util/yaml_test.dart:61: });
On 2015/11/03 01:07:27, Brian Wilkerson wrote:
> Consider also testing
> - merging maps and lists where the maps are not suitable for promotion, and
> - merging two values that are neither maps nor lists.

Fantastic.  Thanks for the nudge.  It turns out my `is` check with reified types
was failing at runtime!  Specifically,

  {'foo': bar} is Map<Object,bool>

was evaluating to `true` which was NOT what I expected.

Cheers!

[pquitslund, 2015-11-03 18:39:42]

On 2015/11/03 18:38:09, pquitslund wrote:
> Thank you!
> 
>
https://codereview.chromium.org/1425393002/diff/1/pkg/analyzer/test/src/util/...
> File pkg/analyzer/test/src/util/yaml_test.dart (right):
> 
>
https://codereview.chromium.org/1425393002/diff/1/pkg/analyzer/test/src/util/...
> pkg/analyzer/test/src/util/yaml_test.dart:29: }
> On 2015/11/03 01:07:27, Brian Wilkerson wrote:
> > Add a sibling to "three" to ensure that unmatched keys from both sides are
> > retained.
> 
> Done.
> 
>
https://codereview.chromium.org/1425393002/diff/1/pkg/analyzer/test/src/util/...
> pkg/analyzer/test/src/util/yaml_test.dart:35: 'nested': {'four': false,
'five':
> true},
> On 2015/11/03 01:07:27, Brian Wilkerson wrote:
> > Can't actually tell whether the resulting value for "nested" is the result
of
> a
> > merge or just the second value.
> 
> Fixed.
> 
>
https://codereview.chromium.org/1425393002/diff/1/pkg/analyzer/test/src/util/...
> pkg/analyzer/test/src/util/yaml_test.dart:61: });
> On 2015/11/03 01:07:27, Brian Wilkerson wrote:
> > Consider also testing
> > - merging maps and lists where the maps are not suitable for promotion, and
> > - merging two values that are neither maps nor lists.
> 
> Fantastic.  Thanks for the nudge.  It turns out my `is` check with reified
types
> was failing at runtime!  Specifically,
> 
>   {'foo': bar} is Map<Object,bool>
> 
> was evaluating to `true` which was NOT what I expected.

https://dartpad.dartlang.org/09ed1376549c6c4362ce

> 
> Cheers!

[pquitslund, 2015-11-03 18:42:22]

Committed patchset #2 (id:20001) manually as
67dc108f391937786a15c8adc17667486cf34548 (presubmit successful).