WIP Initial commit

This creates a Swift package with an example app, linting and formatting
commands, CI pipeline, README, and contributing guidelines.

In the absence of guidance about which minimum Swift version to use, I
decided to use the latest release at time of writing (5.10). We can
revisit this later if need be.

TODO what is this in Xcode? skipping cache due to an error:
https://github.com/apple/swift-argument-parser: The repository could not
be found. Make sure a valid repository exists at the specified location
and try again.

TODO why Mint? and explain Mint cache

TODO document:
Note that .swift-version is required and that the swift-tools-version
from Package.swift is not used; see [1].

[1] nicklockwood/SwiftFormat#1496

TODO explain strict concurrency

TODO explain add SwiftLint rules from AAT @ b39e5187: who knows if these
will turn out to be what we want, but it’ll do as a starting point

TODO explain turn on private_swiftui_state

TODO explain invert SwiftLint’s default trailing comma rule for
compability with SwiftFormat

Upon realising this clash, I hoped we could get away with just using
SwiftLint, which does have some style rules. But it doesn’t enforce some
basic things like indentation. I hope that there aren’t further clashes
between the two tools, but we won’t find out until we write more code.

TODO explain build scripts

TODO explain why build scripts are part of main package
(the issue here is that i couldn't access the files in script/ when there
was a separate package there — main package didn't show them in xcode,
and subpackage didn't open as anything useful)
test mint cache

TODO explain all of the Package.resolved files

TODO fix-then-check?

.github/workflows/check.yaml

@@ -0,0 +1,114 @@
+name: Check
+
+on:
+  workflow_dispatch:
+  pull_request:
+  push:
+    branches:
+      - main
+jobs:
+  lint:
+    runs-on: macos-latest
+
+    # From actions/cache documentation linked to below
+    env:
+      MINT_PATH: .mint/lib
+      MINT_LINK_PATH: .mint/bin
+
+    steps:
+      - uses: actions/checkout@v4
+
+      # https://github.com/actions/cache/blob/40c3b67b2955d93d83b27ed164edd0756bc24049/examples.md#swift---mint
+      - uses: actions/cache@v4
+        with:
+          path: .mint
+          key: ${{ runner.os }}-mint-${{ hashFiles('**/Mintfile') }}
+          restore-keys: |
+            ${{ runner.os }}-mint-
+
+      - run: npm ci
+      - run: brew install mint
+      - run: mint bootstrap
+
+      - run: script/format/check
+      - run: script/lint/check
+
+  generate-matrices:
+    runs-on: macos-latest
+    outputs:
+      matrix: ${{ steps.generation-step.outputs.matrix }}
+    steps:
+      - uses: actions/checkout@v4
+      - id: generation-step
+        run: swift run BuildTool generate-matrices >> $GITHUB_OUTPUT
+
+  check-spm:
+    name: SPM (Xcode ${{ matrix.tooling.xcodeVersion }}, Swift ${{ matrix.tooling.swiftVersion }})
+    runs-on: macos-latest
+    needs: generate-matrices
+    strategy:
+      fail-fast: false
+      matrix: ${{ fromJson(needs.generate-matrices.outputs.matrix).withoutPlatform }}
+
+    steps:
+      - uses: actions/checkout@v4
+      - uses: maxim-lobanov/setup-xcode@v1
+        with:
+          xcode-version: ${{ matrix.tooling.xcodeVersion }}
+
+      # https://forums.swift.org/t/warnings-as-errors-for-libraries-frameworks/58393/2
+      - run: swift build -Xswiftc -warnings-as-errors -Xswiftc -swift-version -Xswiftc ${{ matrix.tooling.swiftVersion }}
+      - run: swift test -Xswiftc -warnings-as-errors -Xswiftc -swift-version -Xswiftc ${{ matrix.tooling.swiftVersion }}
+
+  check-xcode:
+    name: Xcode, ${{matrix.platform}} (Xcode ${{ matrix.tooling.xcodeVersion }}, Swift ${{ matrix.tooling.swiftVersion }})
+    runs-on: macos-latest
+    needs: generate-matrices
+
+    strategy:
+      fail-fast: false
+      matrix: ${{ fromJson(needs.generate-matrices.outputs.matrix).withPlatform }}
+
+    steps:
+      - uses: actions/checkout@v4
+      - uses: maxim-lobanov/setup-xcode@v1
+        with:
+          xcode-version: ${{ matrix.tooling.xcodeVersion }}
+
+      - name: Build and run tests
+        run: swift run BuildTool build-and-test-library --platform ${{ matrix.platform }} --swift-version ${{ matrix.tooling.swiftVersion }}
+
+  check-example-app:
+    name: Example app, ${{matrix.platform}} (Xcode ${{ matrix.tooling.xcodeVersion }}, Swift ${{ matrix.tooling.swiftVersion }})
+    runs-on: macos-latest
+    needs: generate-matrices
+
+    strategy:
+      fail-fast: false
+      matrix: ${{ fromJson(needs.generate-matrices.outputs.matrix).withPlatform }}
+
+    steps:
+      - uses: actions/checkout@v4
+      - uses: maxim-lobanov/setup-xcode@v1
+        with:
+          xcode-version: ${{ matrix.tooling.xcodeVersion }}
+
+      - name: Build example app
+        run: swift run BuildTool build-example-app --platform ${{ matrix.platform }} --swift-version ${{ matrix.tooling.swiftVersion }}
+
+  # We use this job as a marker that all of the required checks have completed.
+  # This allows us to configure a single required status check in our branch
+  # protection rules instead of having to type loads of different check names
+  # into the branch protection web UI (and keep this list up to date as we
+  # change the matrices).
+  all-checks-completed:
+    runs-on: ubuntu-latest
+    needs:
+      - lint
+      - check-spm
+      - check-xcode
+      - check-example-app
+
+    steps:
+      - name: No-op
+        run: "true"

.gitignore

@@ -0,0 +1,16 @@
+# Start of .gitignore created by Swift Package Manager
+.DS_Store
+/.build
+/Packages
+xcuserdata/
+DerivedData/
+.swiftpm/configuration/registries.json
+.swiftpm/xcode/package.xcworkspace/contents.xcworkspacedata
+.netrc
+# End of .gitignore created by Swift Package Manager
+
+/node_modules
+/.mint
+
+# Don’t try and format the asset catalogue JSON files which are managed by Xcode
+*.xcassets/

.prettierignore

@@ -0,0 +1,2 @@
+# Don’t try and format the asset catalogue JSON files, which are managed by Xcode
+*.xcassets/

.prettierrc

@@ -0,0 +1 @@
+{}

.swift-version

@@ -0,0 +1 @@
+5.10

.swiftlint.yml

@@ -0,0 +1,102 @@
+excluded:
+  - .build
+
+strict: true
+
+disabled_rules:
+  # All of the default rules of type "metrics". We have no reason to believe that the arbitrary defaults picked by SwiftLint are helpful.
+  - cyclomatic_complexity
+  - file_length
+  - function_body_length
+  - function_parameter_count
+  - large_tuple
+  - line_length
+  - nesting
+  - type_body_length
+
+  # Rules of type "lint" that we’ve decided we don’t want:
+  - todo # We frequently use TODOs accompanied by a GitHub issue reference
+
+opt_in_rules:
+  # All of the opt-in rules of type "performance":
+  - contains_over_filter_count
+  - contains_over_filter_is_empty
+  - contains_over_first_not_nil
+  - contains_over_range_nil_comparison
+  - empty_collection_literal
+  - empty_count
+  - empty_string
+  - first_where
+  - flatmap_over_map_reduce
+  - last_where
+  - reduce_into
+  - sorted_first_last
+
+  # Opt-in rules of type "style" that we’ve decided we want:
+  - attributes
+  - closure_end_indentation
+  - closure_spacing
+  - collection_alignment
+  - comma_inheritance
+  - conditional_returns_on_newline
+  - file_header
+  - implicit_return
+  - literal_expression_end_indentation
+  - modifier_order
+  - multiline_arguments
+  - multiline_arguments_brackets
+  - multiline_function_chains
+  - multiline_literal_brackets
+  - multiline_parameters
+  - multiline_parameters_brackets
+  - operator_usage_whitespace
+  - prefer_self_type_over_type_of_self
+  - self_binding
+  - single_test_class
+  - sorted_imports
+  - switch_case_on_newline
+  - trailing_closure
+  - trailing_newline
+  - unneeded_parentheses_in_closure_argument
+  - vertical_parameter_alignment_on_call
+  - vertical_whitespace_closing_braces
+  - vertical_whitespace_opening_braces
+
+  # Opt-in rules of type "idiomatic" that we’ve decided we want:
+  - anonymous_argument_in_multiline_closure
+  - convenience_type
+  - fallthrough
+  - fatal_error_message
+  - pattern_matching_keywords
+  - redundant_type_annotation
+  - shorthand_optional_binding
+  - static_operator
+  - toggle_bool
+  - xct_specific_matcher
+
+  # Opt-in rules of type "lint" that we’ve decided we want:
+  - array_init
+  - empty_xctest_method
+  - missing_docs
+  - override_in_extension
+  - yoda_condition
+  - private_swiftui_state
+
+file_header:
+  # Comments, except for the required and standard ones at the top of a Package.swift file
+  forbidden_pattern: //(?! (swift-tools-version:|The swift-tools-version declares the minimum version of Swift required to build this package\.))
+
+identifier_name:
+  &no_length_checks # We disable the length checks, for the same reason we disable the rules of type "metrics".
+  min_length:
+    warning: 1
+  max_length:
+    warning: 10000
+
+type_name: *no_length_checks
+
+generic_type_name: *no_length_checks
+
+# For compatibility with SwiftFormat
+trailing_comma:
+  mandatory_comma: true

.swiftpm/configuration/Package.resolved

@@ -0,0 +1,42 @@
+{
+  "originHash" : "9d852a8f936d58dcf5f543508d205baeff66d9e230197f5987ee4f89aa7b1bf1",
+  "pins" : [
+    {
+      "identity" : "ably-cocoa",
+      "kind" : "remoteSourceControl",
+      "location" : "https://github.com/ably/ably-cocoa",
+      "state" : {
+        "revision" : "7f639c609e50053abd4590f34333f9472645558a",
+        "version" : "1.2.33"
+      }
+    },
+    {
+      "identity" : "delta-codec-cocoa",
+      "kind" : "remoteSourceControl",
+      "location" : "https://github.com/ably/delta-codec-cocoa",
+      "state" : {
+        "revision" : "3ee62ea40a63996b55818d44b3f0e56d8753be88",
+        "version" : "1.3.3"
+      }
+    },
+    {
+      "identity" : "msgpack-objective-c",
+      "kind" : "remoteSourceControl",
+      "location" : "https://github.com/rvi/msgpack-objective-C",
+      "state" : {
+        "revision" : "3e36b48e04ecd756cb927bd5f5b9bf6d45e475f9",
+        "version" : "0.4.0"
+      }
+    },
+    {
+      "identity" : "swift-argument-parser",
+      "kind" : "remoteSourceControl",
+      "location" : "https://github.com/apple/swift-argument-parser",
+      "state" : {
+        "revision" : "41982a3656a71c768319979febd796c6fd111d5c",
+        "version" : "1.5.0"
+      }
+    }
+  ],
+  "version" : 3
+}

.swiftpm/xcode/package.xcworkspace/xcshareddata/WorkspaceSettings.xcsettings

@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+	<key>IDEWorkspaceSharedSettings_AutocreateContextsIfNeeded</key>
+	<true/>
+</dict>
+</plist>

.swiftpm/xcode/xcshareddata/xcschemes/AblyChat.xcscheme

@@ -0,0 +1,79 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<Scheme
+   LastUpgradeVersion = "1540"
+   version = "1.7">
+   <BuildAction
+      parallelizeBuildables = "YES"
+      buildImplicitDependencies = "YES"
+      buildArchitectures = "Automatic">
+      <BuildActionEntries>
+         <BuildActionEntry
+            buildForTesting = "YES"
+            buildForRunning = "YES"
+            buildForProfiling = "YES"
+            buildForArchiving = "YES"
+            buildForAnalyzing = "YES">
+            <BuildableReference
+               BuildableIdentifier = "primary"
+               BlueprintIdentifier = "AblyChat"
+               BuildableName = "AblyChat"
+               BlueprintName = "AblyChat"
+               ReferencedContainer = "container:">
+            </BuildableReference>
+         </BuildActionEntry>
+      </BuildActionEntries>
+   </BuildAction>
+   <TestAction
+      buildConfiguration = "Debug"
+      selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
+      selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      shouldUseLaunchSchemeArgsEnv = "YES"
+      shouldAutocreateTestPlan = "YES">
+      <Testables>
+         <TestableReference
+            skipped = "NO">
+            <BuildableReference
+               BuildableIdentifier = "primary"
+               BlueprintIdentifier = "AblyChatTests"
+               BuildableName = "AblyChatTests"
+               BlueprintName = "AblyChatTests"
+               ReferencedContainer = "container:">
+            </BuildableReference>
+         </TestableReference>
+      </Testables>
+   </TestAction>
+   <LaunchAction
+      buildConfiguration = "Debug"
+      selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
+      selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      launchStyle = "0"
+      useCustomWorkingDirectory = "NO"
+      ignoresPersistentStateOnLaunch = "NO"
+      debugDocumentVersioning = "YES"
+      debugServiceExtension = "internal"
+      allowLocationSimulation = "YES">
+   </LaunchAction>
+   <ProfileAction
+      buildConfiguration = "Release"
+      shouldUseLaunchSchemeArgsEnv = "YES"
+      savedToolIdentifier = ""
+      useCustomWorkingDirectory = "NO"
+      debugDocumentVersioning = "YES">
+      <MacroExpansion>
+         <BuildableReference
+            BuildableIdentifier = "primary"
+            BlueprintIdentifier = "AblyChat"
+            BuildableName = "AblyChat"
+            BlueprintName = "AblyChat"
+            ReferencedContainer = "container:">
+         </BuildableReference>
+      </MacroExpansion>
+   </ProfileAction>
+   <AnalyzeAction
+      buildConfiguration = "Debug">
+   </AnalyzeAction>
+   <ArchiveAction
+      buildConfiguration = "Release"
+      revealArchiveInOrganizer = "YES">
+   </ArchiveAction>
+</Scheme>

AblyChat.xcworkspace/xcshareddata/IDEWorkspaceChecks.plist

@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+	<key>IDEDidComputeMac32BitWarning</key>
+	<true/>
+</dict>
+</plist>