[camera_avfoundation] Adds support for discovering external camera devices on iOS 17 onwards.

[bibaswan-bhawal]

This PR adds support for discovering external cameras in iOS devices with USB-C i.e. iPad.

This should address https://github.com/flutter/flutter/issues/130073

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• [x] I listed at least one issue that this PR fixes in the description above.
• [x] I updated pubspec.yaml with an appropriate new version according to the pub versioning philosophy, or this PR is exempt from version changes.
• [x] I updated CHANGELOG.md to add a description of the change, following repository CHANGELOG style.
• [x] I updated/added relevant documentation (doc comments with ///).
• [x] I added new tests to check the change I am making, or this PR is test-exempt.
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[bibaswan-bhawal]

I was having trouble getting the changelog command working throwing

ProcessException: fatal: Not a valid object name upstream\main
  Command: git merge-base upstream\main HEAD

any insight would be helpful, then I can resolve some of the failing checks

[bibaswan-bhawal]

The error thrown by XCode says that Use of undeclared identifier 'AVCaptureDeviceTypeExternal' but this is known to be a correct identifer tested on XCode 15 and the package builds and runs correctly when run using XCode 15.2

[stuartmorgan-g]

I was having trouble getting the changelog command working throwing

ProcessException: fatal: Not a valid object name upstream\main
  Command: git merge-base upstream\main HEAD

any insight would be helpful, then I can resolve some of the failing checks

See https://github.com/flutter/packages/blob/main/script/tool/README.md#update-changelog-and-version, in particular the last paragraph. If you use a different repo setup than our docs recommend, then you need to modify commands that reference repositories and branches accordingly.

[stuartmorgan-g]

but this is known to be a correct identifer tested on XCode 15

Our CI currently uses Xcode 14; updating is still an ongoing project.

[bibaswan-bhawal]

I guess the PR is blocked until the CI is updated to xcode 15?

[stuartmorgan-g]

Landing it is blocked on https://github.com/flutter/flutter/issues/132237, but it can be reviewed in the meantime.

[hellohuanlin]

@bibaswan-bhawal The change makes sense. Does external camera work after this change? (e.g. preview, taking picture/video, etc)

[bibaswan-bhawal]

Yes they do

[hellohuanlin]

@stuartmorgan does your comment from the other PR (https://github.com/flutter/packages/pull/5957#issuecomment-1906818335) also apply to this PR?

[stuartmorgan-g]

@stuartmorgan does your comment from the other PR (#5957 (comment)) also apply to this PR?

In theory yes; I realized after writing that though that this specific case is probably not something we need to block on. camera_windows already has this problem, and in some cases Android as well (we don't discover external cameras, but on some Android devices apparently external cameras that are plugged in when the device boots are reported as non-external, and thus are discovered). So on some platforms we already have the problem that if someone removes a camera while using a Flutter app, the app probably doesn't have a good way to gracefully handle that. And it's a pretty niche case; I think most people are probably not going to remove cameras they are actively using most of the time.

So I'll file an issue about the need to add API to get notifications about camera availability changes, but I'm okay not blocking this specific change on that.

[stuartmorgan-g]

So I'll file an issue about the need to add API to get notifications about camera availability changes

https://github.com/flutter/flutter/issues/142239

[bibaswan-bhawal]

Fixed all broken tests

[stuartmorgan-g]

@bibaswan-bhawal Is this ready for re-review?

[vashworth]

@bibaswan-bhawal Please mark as ready for review when you'd like it to be re-reviewed.

[stuartmorgan-g]

Since this is marked as a draft and hasn't been updated in several months I'm going to close it to clean out our review queue. Please don't hesitate to submit a new PR if you decide to revisit this. Thanks!