"kpm restore" ignores nonexistent local package feeds and gives warnings

[ChengTian]

parent #845

kpm restore gives warning instead of blowing up now.

Also extracted some shared code to have DRYer code.

[ChengTian]

Moving initialization of IsHttp here can simplify extraction of shared code (PackageSourceUtils.CreatePackageFeed()). Moreover, the source argument already contains IsHttp information, so passing isHttp introduces duplicated info.

[ChengTian]

@davidfowl , thanks for the feedbacks. Please check the latest commits.

[Praburaj]

Is this PR related to this bug? #1018 ?

[Praburaj]

The issue addressed with this PR and the bug #1018 seems to be similar/same except the difference of local or remote source. If --ignore-failed-sources needs to be used for http sources to ignore on failure it will be good to have the same behavior for local sources.

[ChengTian]

Talked to @Praburaj and here is a summary:
If we take the current PR, local feeds and remote feeds will have inconsistent behaviors.
Local feeds: if not accessible, always show warning and skip it
Remote feeds: if not accessible, kpm restore exits with errors; if not accessible but --ignore-failed-sources is given, show warning and skip it

I think @Praburaj is right. It's ideal if local feeds and remote feeds have consistent behaviors. However, with a nonexistent folder, we cannot determine type of the local feed (KpmPackageFolder or NuGetPackageFolder) so we cannot proceed to the next step of kpm restore. To have the same behavior as remote feeds, we can create a class NonexistentPackageFolder : IPackageFeed, in which FindPackagesByIdAsync throws exception when ``--ignore-failed-sources` is not given.

[ChengTian]

Made behaviors of local feeds more consistent with remote feeds:

• When kpm restore from nonexistent local feed:
  
  
• When kpm restore --ignore-failed-sources from nonexistent local feed, we give a warning and ignore the failed feed:
  

[Praburaj]

Can we highlight the warning message with a different color code. The message looks buried a bit.

[ChengTian]

@Praburaj , the output above is using the same color code as remote feed error messages. If we want to change the color code, we should change both local and remote feeds in a separate PR. Please create an issue for it if you feel strongly. Thanks.

[davidfowl]

[davidfowl]

I don't like this ehhhh

[ChengTian]

If the structure of a folder doesn't conform with NuGetPackageFolder, we always assume it is a KpmPackageFolder. So I remove NonExistentPackageFolder and move the logic to KpmPackageFolder. Do you like this approach? b34cda0

[Praburaj]

@ChengTian sure I filed #1051

[davidfowl]

I guess it's fine,