Powershell: Fix sorting of hashtables

[Hermholtz]

Summary of the new feature/enhancement

In order to sort dictionary (hashtable) an explicit GetEnumerator is required. For example:

> $a = @{a=1;b=2;c=3;d=4}
> $a|sort Name                                                                                                                                       
Name                           Value
----                           -----
c                              3
d                              4
b                              2
a                              1

(doesn't work)

> $a.GetEnumerator()|sort Name                                                                                                                       
Name                           Value
----                           -----
a                              1
b                              2
c                              3
d                              4

(works fine)

Proposed technical implementation details (optional)

Make a change so that

> $a|sort Name                                                                                                                                       

works as expected. Current behavior benefits nobody.

[mklement0]

While it may be surprising, [hashtable] instances have always been treated as a _single object_ in the pipeline, and changing that now would be a massively breaking change.

Think of [hashtable] instances as _single objects_, whose _properties_ (hashtable entries) you wouldn't expect to be enumerated in the pipeline either.

[Hermholtz]

At first it's really surprising and confusing. Then it starts to make sense. However maybe there should be friendlier way than using a method which is very rarely used even by .NET developers.

[mklement0]

I agree that it's not obvious, but the need for it is too rare to warrant a dedicated operator for it in PowerShell, I think.

Note that your specific scenario is at least explicitly documented in the conceptual about_Hash_Tables topic.

Also note that, as stated in the linked topic, you're not sorting the hashtable itself (which is impossible); instead, you're outputting a sorted array of key-value pairs.

[mklement0]

P.S.: A simple alternative is to cast to System.Collections.SortedList:

PS> $ht = @{ zz = 1; gg = 2; aa = 3 }; [System.Collections.SortedList] $ht

Name                           Value
----                           -----
aa                             3
gg                             2
zz                             1