Update 'master' branch references to 'main' branch

Summary:
G'day folks! As promised, I'm spending a bit of my free time seeing what I can do to update and refresh the IGListKit repo on GitHub.

I noticed last night some strange behaviour in that the GitHub Actions CI wasn't running when new commits were merged into the main branch. I discovered the cause of this was because the `CI.yml` file still had `master` in its build rules instead of `main`. And once I noticed that, I noticed there were a lot of other references to the main branch being called `master` in a lot of the documentation.

Thankfully within the documentation, GitHub was smart enough to automatically redirect all of the `master` URLs to `main`, so nothing visibly broke, but I definitely think we should update all of that. :)

I went through the entire repo and did a thorough audit in all of its text files, and updated the main branch name accordingly.

Reviewed By: DimaVartanian

Differential Revision: D42990133

fbshipit-source-id: d6b06c40b1b959990856b46b048895e3c55a9870

.github/CONTRIBUTING.md

@@ -6,7 +6,7 @@ please open an issue on GitHub.
 
 ## Pull Requests
 
-1. Fork the repo and create your branch from `master`.
+1. Fork the repo and create your branch from `main`.
 2. If you've added code that should be tested, add tests.
 3. If you've changed APIs, update the documentation.
 4. Ensure the test suite passes.
@@ -16,7 +16,7 @@ please open an issue on GitHub.
 
 ## Experimental changes
 
-If your change can't be unit tested, we might ask that you add your change as an experiment so that we can verify your change works. To do this, first add a new option to [IGListExperiment](https://github.com/Instagram/IGListKit/blob/master/Source/Common/IGListExperiments.h#L17).
+If your change can't be unit tested, we might ask that you add your change as an experiment so that we can verify your change works. To do this, first add a new option to [IGListExperiment](https://github.com/Instagram/IGListKit/blob/main/Source/Common/IGListExperiments.h#L17).
 
 Then, use an `experiments` bitmask wherever your change is and wrap it in a check to see if it is enabled:
 
@@ -30,11 +30,11 @@ Once your experiment is confirmed we will remove the option and wrapping check!
 
 ## How we do major and minor releases
 
-Everything merges into master. When we cut a release, we merge from `master` into `stable`, tag, and push to CocoaPods.
+Everything merges into `main`. When we cut a release, we merge from `main` into `stable`, tag, and push to CocoaPods.
 
 *Example:*
 
-If current release is `2.1.0`, then any commits for `2.2.0` go into `stable` while commits for `3.0` would go to `master`.
+If current release is `2.1.0`, then any commits for `2.2.0` go into `stable` while commits for `3.0` would go to `main`.
 
 ## Testing
 

.github/ISSUE_TEMPLATE.md

@@ -1,6 +1,6 @@
 ## New issue checklist
 
-- [ ] I have reviewed the [`README`](https://github.com/Instagram/IGListKit/blob/master/README.md) and [documentation](http://instagram.github.io/IGListKit)
+- [ ] I have reviewed the [`README`](https://github.com/Instagram/IGListKit/blob/main/README.md) and [documentation](http://instagram.github.io/IGListKit)
 - [ ] I have searched [existing issues](https://github.com/Instagram/IGListKit/issues) and this is not a duplicate
 - [ ] I have attempted to reproduce the issue and include an example project.
 

.github/PULL_REQUEST_TEMPLATE.md

@@ -7,4 +7,4 @@ Issue fixed: #
 - [ ] All tests pass. Demo project builds and runs.
 - [ ] I added tests, an experiment, or detailed why my change isn't tested.
 - [ ] I added an entry to the `CHANGELOG.md` for any breaking changes, enhancements, or bug fixes.
-- [ ] I have reviewed the [contributing guide](https://github.com/Instagram/IGListKit/blob/master/.github/CONTRIBUTING.md)
+- [ ] I have reviewed the [contributing guide](https://github.com/Instagram/IGListKit/blob/main/.github/CONTRIBUTING.md)

.github/RELEASE_CHECKLIST.md

@@ -8,7 +8,7 @@ Here are the steps for creating and publishing a new release for `IGListKit`.
 - Update pod spec version
 - Update xcodeproj version
 - Run `pod install` on all examples (**must happen on FB internal** because of sync issues)
-- Merge `master` into `stable` via cmd-line and push
+- Merge `main` into `stable` via cmd-line and push
 - Confirm `stable` is `0|0` [ahead/behind](https://github.com/Instagram/IGListKit/branches)
 - Create [GitHub release](https://github.com/Instagram/IGListKit/releases) from `stable`
 - Paste changelog into GH release notes

.github/workflows/CI.yml

@@ -3,7 +3,7 @@ name: "IGListKit CI"
 on: 
   push:
     branches: 
-      - master
+      - main
   pull_request:
     branches: 
       - '*'

.travis.yml

@@ -9,7 +9,7 @@ addons:
 
 branches:
   only:
-    - master
+    - main
     - stable
     - travis-stages
 

CHANGELOG.md

@@ -431,7 +431,7 @@ This release closes the [2.1.0 milestone](https://github.com/Instagram/IGListKit
 
 - Added support for macOS. Note: this is *only* for the Diffing components. There is **no support** for `IGListAdapter`, `IGListSectionController`, and other components at this time. [Guilherme Rambo](https://github.com/insidegui) [(#235)](https://github.com/Instagram/IGListKit/pull/235)
 
-- Added a [macOS example](https://github.com/Instagram/IGListKit/tree/master/Examples/Examples-macOS) project. [Guilherme Rambo](https://github.com/insidegui) [(#337)](https://github.com/Instagram/IGListKit/pull/337)
+- Added a [macOS example](https://github.com/Instagram/IGListKit/tree/main/Examples/Examples-macOS) project. [Guilherme Rambo](https://github.com/insidegui) [(#337)](https://github.com/Instagram/IGListKit/pull/337)
 
 - Disables `prefetchEnabled` by default on `IGListCollectionView`. [Sven Bacia](https://github.com/svenbacia) [(#323)](https://github.com/Instagram/IGListKit/pull/323)
 
@@ -506,7 +506,7 @@ You can find a [migration guide here](https://instagram.github.io/IGListKit/migr
 
 - Added support for cells created from nibs. [Sven Bacia](https://github.com/svenbacia) [(#56)](https://github.com/Instagram/IGListKit/pull/56)
 
-- Added an additional initializer for `IGListSingleSectionController` to be able to support single sections created from nibs. An example can be found [here](https://github.com/Instagram/IGListKit/tree/master/Examples/Examples-iOS/IGListKitExamples/ViewControllers/SingleSectionViewController.swift). [(#56)](https://github.com/Instagram/IGListKit/pull/56)
+- Added an additional initializer for `IGListSingleSectionController` to be able to support single sections created from nibs. An example can be found [here](https://github.com/Instagram/IGListKit/tree/main/Examples/Examples-iOS/IGListKitExamples/ViewControllers/SingleSectionViewController.swift). [(#56)](https://github.com/Instagram/IGListKit/pull/56)
 
 ```objc
 - (instancetype)initWithNibName:(NSString *)nibName

Dangerfile

@@ -24,7 +24,7 @@ has_doc_changes = !git.modified_files.grep(/docs\//).empty?
 has_doc_gen_title = github.pr_title.include? "#docgen"
 if has_doc_changes && !has_doc_gen_title
   fail("Docs are regenerated when creating new releases.")
-  message("Docs are generated by using [Jazzy](https://github.com/realm/jazzy). If you want to contribute, please update [markdown guides](https://github.com/Instagram/IGListKit/tree/master/Guides)")
+  message("Docs are generated by using [Jazzy](https://github.com/realm/jazzy). If you want to contribute, please update [markdown guides](https://github.com/Instagram/IGListKit/tree/main/Guides)")
 end
 
 # Warn if Source files were added or removed but examples are not updated

Guides/Best Practices and FAQ.md

@@ -4,7 +4,7 @@ This guide provides notes and details on best practices in using `IGListKit`, ge
 
 ## Best Practices
 
-- We recommend adding an assert to check [`-isKindOfClass:`](https://developer.apple.com/reference/objectivec/1418956-nsobject/1418511-iskindofclass) on the object you receive in [`-didUpdateToObject:`](https://github.com/Instagram/IGListKit/blob/master/Source/IGListSectionController.h#L63-L72) in your section controllers. 
+- We recommend adding an assert to check [`-isKindOfClass:`](https://developer.apple.com/reference/objectivec/1418956-nsobject/1418511-iskindofclass) on the object you receive in [`-didUpdateToObject:`](https://github.com/Instagram/IGListKit/blob/main/Source/IGListSectionController.h#L63-L72) in your section controllers. 
 This makes it easy to track down easily-overlooked mistakes in your [`IGListAdapaterDataSource`](https://instagram.github.io/IGListKit/Protocols/IGListAdapterDataSource.html#/c:objc(pl)IGListAdapterDataSource(im)listAdapter:sectionControllerForObject:) implementation. 
 If this assert is ever hit, that means `IGListKit` has sent your section controller the incorrect type of object. 
 This would only happen if your objects provide *non-unique* diff identifiers. 
@@ -33,7 +33,7 @@ func didUpdate(to object: Any) {
 
 #### I upgraded IGListKit and now everything is broken!
 
-Check out our [migration guide](https://github.com/Instagram/IGListKit/blob/master/Guides/Migration.md) to make upgrading easier.
+Check out our [migration guide](https://github.com/Instagram/IGListKit/blob/main/Guides/Migration.md) to make upgrading easier.
 
 #### How do you implement separators between cells?
 
@@ -45,7 +45,7 @@ See discussion in [#316](https://github.com/Instagram/IGListKit/issues/316)
 
 #### The documentation and examples have `<X>` feature or changes, but I don't have it in my version. Why?
 
-This feature is on the `master` branch only and hasn't been officially tagged and [released](https://github.com/Instagram/IGListKit/releases). If you need to, you can [install from the `master` branch](https://instagram.github.io/IGListKit/installation.html).
+This feature is on the `main` branch only and hasn't been officially tagged and [released](https://github.com/Instagram/IGListKit/releases). If you need to, you can [install from the `main` branch](https://instagram.github.io/IGListKit/installation.html).
 
 #### Does `IGListKit` work with...?
 
@@ -76,7 +76,7 @@ If you have multiple thousands of items and you cannot batch them in, you'll see
 
 #### How do I use IGListKit and estimated cell sizes with Auto Layout?
 
-This should work in theory, and we have an [example section controller](https://github.com/Instagram/IGListKit/blob/master/Examples/Examples-iOS/IGListKitExamples/SectionControllers/SelfSizingSectionController.swift), but the estimated-size API in `UICollectionViewFlowLayout` has changed dramatically over different iOS versions, making first-class support in IGListKit difficult. We don't use estimated cell sizes or Auto Layout in Instagram and cannot commit to fully supporting it.
+This should work in theory, and we have an [example section controller](https://github.com/Instagram/IGListKit/blob/main/Examples/Examples-iOS/IGListKitExamples/SectionControllers/SelfSizingSectionController.swift), but the estimated-size API in `UICollectionViewFlowLayout` has changed dramatically over different iOS versions, making first-class support in IGListKit difficult. We don't use estimated cell sizes or Auto Layout in Instagram and cannot commit to fully supporting it.
 
 See [#516](https://github.com/Instagram/IGListKit/issues/516) for a master list of all known issues. We very much welcome contribution to fixing this!
 
@@ -114,7 +114,7 @@ Give [this box](https://github.com/Instagram/IGListKit/issues/35#issuecomment-27
 
 #### I want to deliver messages to certain section controllers, how do I do that?
 
-We recommend using dependency injection and announcing changes, demonstrated in [our example](https://github.com/Instagram/IGListKit/blob/master/Examples/Examples-iOS/IGListKitExamples/ViewControllers/AnnouncingDepsViewController.swift).
+We recommend using dependency injection and announcing changes, demonstrated in [our example](https://github.com/Instagram/IGListKit/blob/main/Examples/Examples-iOS/IGListKitExamples/ViewControllers/AnnouncingDepsViewController.swift).
 
 #### Should I reuse my section controllers between models?
 
@@ -124,19 +124,19 @@ No! `IGListKit` is designed to have a 1:1 instance mapping between objects and s
 
 #### Why does `UICollectionViewFlowLayout` put everything in a new row?
 
-`UICollectionViewFlowLayout` has its limitations, and it's not well designed to support sections on the same "line". Instead you should use [`IGListCollectionViewLayout`](https://github.com/Instagram/IGListKit/blob/master/Source/IGListCollectionViewLayout.h).
+`UICollectionViewFlowLayout` has its limitations, and it's not well designed to support sections on the same "line". Instead you should use [`IGListCollectionViewLayout`](https://github.com/Instagram/IGListKit/blob/main/Source/IGListCollectionViewLayout.h).
 
 #### What if I just want a section controller and don't need the object?
 
-Feel free to use a static string or number as your model. You can use this object as a "key" to find your section controller. Take a look at our [example](https://github.com/Instagram/IGListKit/blob/master/Examples/Examples-iOS/IGListKitExamples/ViewControllers/SearchViewController.swift#L34) of this.
+Feel free to use a static string or number as your model. You can use this object as a "key" to find your section controller. Take a look at our [example](https://github.com/Instagram/IGListKit/blob/main/Examples/Examples-iOS/IGListKitExamples/ViewControllers/SearchViewController.swift#L34) of this.
 
 #### How do I make my cells diff and animate?
 
-Use [`IGListBindingSectionController`](https://github.com/Instagram/IGListKit/blob/master/Source/IGListBindingSectionController.h) to automatically diff and animate your cells.
+Use [`IGListBindingSectionController`](https://github.com/Instagram/IGListKit/blob/main/Source/IGListBindingSectionController.h) to automatically diff and animate your cells.
 
 #### How can I power and update the number of items in a section controller with a dynamic array?
 
-We recommend creating a model that owns an array to the items that power `numberOfItems`. Checkout our [Post example](https://github.com/Instagram/IGListKit/blob/master/Examples/Examples-iOS/IGListKitExamples/SectionControllers/PostSectionController.m#L32) that has dynamic comment cells. Just be sure to check when your array changes:
+We recommend creating a model that owns an array to the items that power `numberOfItems`. Checkout our [Post example](https://github.com/Instagram/IGListKit/blob/main/Examples/Examples-iOS/IGListKitExamples/SectionControllers/PostSectionController.m#L32) that has dynamic comment cells. Just be sure to check when your array changes:
 
 ```swift
 class Forecast: ListDiffable {

Guides/Getting Started.md

@@ -10,7 +10,7 @@ After installing `IGListKit`, creating a new list is easy.
 
 Creating a new section controller is simple. Subclass `IGListSectionController` and override at least `cellForItemAtIndex:` and `sizeForItemAtIndex:`.
 
-Take a look at [LabelSectionController](https://raw.githubusercontent.com/Instagram/IGListKit/master/Examples/Examples-iOS/IGListKitExamples/SectionControllers/LabelSectionController.swift) for an example section controller that handles a `String` and configures a single cell with a `UILabel`.
+Take a look at [LabelSectionController](https://raw.githubusercontent.com/Instagram/IGListKit/main/Examples/Examples-iOS/IGListKitExamples/SectionControllers/LabelSectionController.swift) for an example section controller that handles a `String` and configures a single cell with a `UILabel`.
 
 ```swift
 class LabelSectionController: ListSectionController {
@@ -153,7 +153,7 @@ let adapter = ListAdapter(updater: ListAdapterUpdater(),
                  workingRangeSize: 1) // 1 before/after visible objects
 ```
 
-![working-range](https://raw.githubusercontent.com/Instagram/IGListKit/master/Resources/workingrange.png)
+![working-range](https://raw.githubusercontent.com/Instagram/IGListKit/main/Resources/workingrange.png)
 
 You can set the weak `workingRangeDelegate` on a section controller to receive events.
 

Guides/Installation.md

@@ -12,15 +12,15 @@ In order to use the latest release of the framework, add the following to your `
 pod 'IGListKit', '~> 4.0'
 ```
 
-### Using `master`
+### Using `main`
 
-Alternatively, you can use the latest version from the [`master` branch](https://github.com/Instagram/IGListKit/tree/master). This is what we use at Instagram, so you can be confident that `master` is always stable and reliable.
+Alternatively, you can use the latest version from the [`main` branch](https://github.com/Instagram/IGListKit/tree/main). This is what we use at Instagram, so you can be confident that `main` is always stable and reliable.
 
 ```ruby
-pod 'IGListKit', :git => 'https://github.com/Instagram/IGListKit.git', :branch => 'master'
+pod 'IGListKit', :git => 'https://github.com/Instagram/IGListKit.git', :branch => 'main'
 ```
 
-> **Note:** while `master` is stable, it may have breaking changes. Before updating to `master`, be sure to check the [`CHANGELOG`](https://github.com/Instagram/IGListKit/blob/master/CHANGELOG.md) for details on changes.
+> **Note:** while `main` is stable, it may have breaking changes. Before updating to `main`, be sure to check the [`CHANGELOG`](https://github.com/Instagram/IGListKit/blob/main/CHANGELOG.md) for details on changes.
 
 ### Subspecs
 

Guides/Migration.md

@@ -37,16 +37,16 @@ If you were using `IGListDiff(...)` _inside_ a section controller to compute dif
 
 You can simply find regex `IGListCollectionView([ |\*|\(])` and replace with regex `UICollectionView$1` in your project to fix this.
 
-![Replace IGListCollectionView](https://raw.githubusercontent.com/Instagram/IGListKit/master/Resources/replace-iglistcollectionview.png)
+![Replace IGListCollectionView](https://raw.githubusercontent.com/Instagram/IGListKit/main/Resources/replace-iglistcollectionview.png)
 
 ### Removed `IGListGridCollectionViewLayout`
 
 Start using `IGListCollectionViewLayout` instead of `IGListGridCollectionViewLayout`.
 
 - `scrollDirection` is not yet supported. If you need horizontal scrolling, please use `UICollectionViewFlowLayout` or file an issue.
-- Set `minimumLineSpacing` on your [section controllers](https://github.com/Instagram/IGListKit/blob/master/Source/IGListSectionController.h#L59-L64) instead of the layout
-- Set `minimumInteritemSpacing` on your [section controllers](https://github.com/Instagram/IGListKit/blob/master/Source/IGListSectionController.h#L66-L71) instead of the layout
-- Return the size of your cells in [sizeForItemAtIndex:](https://github.com/Instagram/IGListKit/blob/master/Source/IGListSectionController.h#L48) instead of setting it on the layout.
+- Set `minimumLineSpacing` on your [section controllers](https://github.com/Instagram/IGListKit/blob/main/Source/IGListSectionController.h#L59-L64) instead of the layout
+- Set `minimumInteritemSpacing` on your [section controllers](https://github.com/Instagram/IGListKit/blob/main/Source/IGListSectionController.h#L66-L71) instead of the layout
+- Return the size of your cells in [sizeForItemAtIndex:](https://github.com/Instagram/IGListKit/blob/main/Source/IGListSectionController.h#L48) instead of setting it on the layout.
 
 ### Item mutations must be wrapped in `-[IGListCollectionContext performBatchAnimated:completion:]`
 

Guides/Modeling and Binding.md

@@ -15,7 +15,7 @@ You can follow along and build the example in this guide. First, you must downlo
 
 Take a look at the following Instagram-inspired list element design:
 
-![Design Specs](https://raw.githubusercontent.com/Instagram/IGListKit/master/Resources/modeling-design.png)
+![Design Specs](https://raw.githubusercontent.com/Instagram/IGListKit/main/Resources/modeling-design.png)
 
 You can already start mentally modelling your data:
 
@@ -234,7 +234,7 @@ You now have the following view models, which can all be derived from each `Post
 
 Let's start using these models to power cells using `ListBindingSectionController`. This controller takes a top-level model (`Post`), asks its data source for an array of diffable view models (our view models above), then binds those view models to cells (provided in the starter project).
 
-![Binding Flow](https://raw.githubusercontent.com/Instagram/IGListKit/master/Resources/binding-flow.png)
+![Binding Flow](https://raw.githubusercontent.com/Instagram/IGListKit/main/Resources/binding-flow.png)
 
 Create **PostSectionController.swift** and add the following code:
 
@@ -470,7 +470,7 @@ func listAdapter(
 
 **Build and run** the sample app to see your post show up!
 
-![Working in the Simulator](https://raw.githubusercontent.com/Instagram/IGListKit/master/Resources/modeling-working.png)
+![Working in the Simulator](https://raw.githubusercontent.com/Instagram/IGListKit/main/Resources/modeling-working.png)
 
 ## Handling Cell Actions
 
@@ -570,7 +570,7 @@ ActionViewModel(likes: localLikes ?? object.likes)
 **Build and run** the app, tap on the heart button, and see your likes increment!
 
 <p align="center">
-  <img src="https://raw.githubusercontent.com/Instagram/IGListKit/master/Resources/modeling-likes.gif" width=300  />
+  <img src="https://raw.githubusercontent.com/Instagram/IGListKit/main/Resources/modeling-likes.gif" width=300  />
 </p>
 
 ## Wrapping up