feat: Add iOS platform support by jding-xyz · Pull Request #153 · apache/arrow-swift

jding-xyz · 2026-03-29T17:44:54Z

What's Changed

I'm working on an iOS project that depends on this library. It already compiles and runs correctly on iOS, but there is no official platform declaration or CI coverage. This PR formalises that support so it stays tested and other iOS developers can adopt it with confidence.

Add .iOS(.v15) to Package.swift platforms
Migrate test data loading from #file-based paths to Bundle.module resources (the #file approach doesn't work in Xcode test bundles)
Write tests output to the system temp directory instead of the source tree (the source tree path is not writable from an iOS test bundle)
Add an iOS Simulator CI job (macos-15 runner, dynamic simulator selection)
Document supported platforms in README

Testing

All existing swift test (macOS/Linux) and lint jobs pass unchanged
New iOS Simulator job passes on macos-15 runner (verified on fork)
Tested locally with xcodebuild test on an iPhone simulator

AI disclosure

An AI coding assistant (Cursor) was used during development. I reviewed, tested, and debugged all changes myself and can fully own them.

Closes #142.

Declare iOS 15+ as a supported platform in Package.swift and document supported platforms in README.md. Made-with: Cursor

Replace #file-based currentDirectory() with Bundle.module resource loading for cross-platform compatibility. Write tests now use the system temporary directory instead of the source tree. Made-with: Cursor

Add xcodebuild test job on macos-15 runner with dynamic simulator selection for resilience against runner image updates. Made-with: Cursor

kou · 2026-03-30T00:46:18Z

@sidpug-arcana Could you review this?

Copilot

Pull request overview

Formalizes iOS support for the Arrow Swift package by declaring iOS as a supported platform, making IPC reader tests work inside Xcode/iOS test bundles, and adding CI coverage for iOS Simulator runs.

Changes:

Declare iOS 15+ support in Package.swift and bundle IPC test .arrow files as SwiftPM test resources.
Update IPC tests to load testdata via Bundle.module and write outputs to the system temp directory (iOS-safe).
Add an iOS Simulator GitHub Actions job and document supported platforms in the README.

Reviewed changes

Copilot reviewed 4 out of 5 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
Tests/ArrowTests/IPCTests.swift	Switch testdata loading to `Bundle.module` and write generated test output files to a temp directory for iOS/Xcode compatibility.
README.md	Document supported platforms including iOS 15+.
Package.swift	Add iOS platform declaration and declare test `.arrow` files as bundled test resources.
.gitignore	Ignore generated `.arrow` files in test and generator directories.
.github/workflows/test.yaml	Add an iOS Simulator CI job (macOS runner, dynamic simulator selection, xcodebuild test).

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Copilot · 2026-03-30T00:48:37Z

Tests/ArrowTests/IPCTests.swift

+        fatalError("Test data file \(filename).arrow not found in bundle. "
+                    + "Run the Go data generator first.")


Using fatalError here will crash the entire test process if the resource is missing, which is harder to diagnose and can mask other failures. Consider making testDataURL throws and using XCTUnwrap/XCTFail so the failure is reported as a normal XCTest failure instead of aborting the run.

Suggested change

fatalError("Test data file \(filename).arrow not found in bundle. "

+ "Run the Go data generator first.")

XCTFail("Test data file \(filename).arrow not found in bundle. "

+ "Run the Go data generator first.")

// Return a neutral placeholder URL so the test process does not crash.

return URL(fileURLWithPath: "/dev/null")

Changed testDataURL to throws, using ArrowError.ioError.

Copilot · 2026-03-30T00:48:38Z

Package.swift

+            resources: [
+                .copy("testdata_bool.arrow"),
+                .copy("testdata_double.arrow"),
+                .copy("testdata_struct.arrow")
+            ],


The test target declares .copy("testdata_*.arrow") resources, but those .arrow files are not present under Tests/ArrowTests/ in this branch. SwiftPM validates resource paths when loading the package, so this will break swift build/dependency resolution unless the files are checked in (or generated by a build tool plugin). Either commit these files (and keep them tracked), or switch to a generation approach that guarantees the resources exist before SwiftPM evaluates the package graph (e.g., a SwiftPM build-tool plugin), otherwise consumers will not be able to build the package.

Suggested change

resources: [

.copy("testdata_bool.arrow"),

.copy("testdata_double.arrow"),

.copy("testdata_struct.arrow")

],

I've committed the three .arrow files. The CI still regenerates them from the Go data generator, so the data should be fresh. This is the only way I was able to find.

kou · 2026-03-30T01:00:53Z

.github/workflows/test.yaml

+          cp *.arrow ../../Tests/ArrowTests/
+      - name: Select iOS Simulator
+        run: |
+          SIMULATOR_ID=$(xcrun simctl list devices available 2>/dev/null | \


Could you add a comment that shows example output of xcrun ... and each filter something like the following?

# Example: # (xcrun ... output) # -> # (awk ... output) # -> # (sort ... output) # -> # (head -1 output) # -> # (grep ... output)

It'll help us when the command line doesn't work as expected.

Added a example from real macos-15 runner output.

kou · 2026-03-30T01:02:17Z

.gitignore

+Tests/ArrowTests/*.arrow
+data-generator/swift-datagen/*.arrow


Could you prepend / like others?

Added as suggested.

kou · 2026-03-30T01:02:45Z

Package.swift

+                .copy("testdata_bool.arrow"),
+                .copy("testdata_double.arrow"),
+                .copy("testdata_struct.arrow")


Can we copy them from ../../data-genrator/swift-datagen/?

Unfortunately SwiftPM's .copy() only accepts paths within the target's source directory, so referencing ../../data-generator/swift-datagen/ isn't possible. Instead I've committed the three generated .arrow files directly (they're small -- 650 to 810 bytes). This ensures the package resolves cleanly without needing to run the Go generator first. The CI still regenerates them, so if the generator changes, any drift will be caught.

OK. But we don't want to add auto generated files into this repository.
Let's copy to Tests/ArrowTests/ manually (or by script) instead of adding them to this repository.

- Commit generated .arrow test data files so SwiftPM resource declarations resolve without running the Go generator first - Replace fatalError in testDataURL with throws for cleaner test failure reporting - Add example pipeline output comments to simulator selection script for easier debugging - Prepend / to .gitignore patterns to match repo conventions Made-with: Cursor

Copilot

Pull request overview

Copilot reviewed 4 out of 8 changed files in this pull request and generated 3 comments.

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Copilot · 2026-03-30T06:17:27Z

.github/workflows/test.yaml

+          xcodebuild test \
+            -scheme Arrow-Package \
+            -destination "platform=iOS Simulator,id=$SIMULATOR_ID" \
+            -only-testing ArrowTests


The new iOS CI job only runs xcodebuild test with -only-testing ArrowTests, which won’t compile (or run) ArrowFlightTests and may not even build the ArrowFlight target. This leaves a gap where the package can be declared iOS-supported but still regress for ArrowFlight on iOS without CI catching it. Consider adding an additional xcodebuild build step for the ArrowFlight scheme (or otherwise ensuring all package products compile) on the selected simulator destination.

Suggested change

-only-testing ArrowTests

-only-testing ArrowTests

- name: Build ArrowFlight for iOS Simulator

run: |

xcodebuild build \

-scheme ArrowFlight \

-destination "platform=iOS Simulator,id=$SIMULATOR_ID"

Copilot · 2026-03-30T06:17:27Z

Tests/ArrowTests/IPCTests.swift

+            "Test data file \(filename).arrow not found in bundle. "
+                + "Run the Go data generator first."


The failure message in testDataURL tells contributors to “Run the Go data generator first,” but the .arrow files are now checked into Tests/ArrowTests and bundled as SwiftPM resources. This can be misleading when the real issue is a missing/incorrect test resource configuration. Consider updating the message to mention verifying the test resources in Package.swift (and running the generator only when regenerating/updating the committed testdata).

Suggested change

"Test data file \(filename).arrow not found in bundle. "

+ "Run the Go data generator first."

"Test data file \(filename).arrow not found in test bundle. "

+ "Verify that the .arrow test resources are correctly declared in Package.swift, "

+ "and run the Go data generator only when regenerating or updating the committed test data."

Copilot · 2026-03-30T06:17:27Z

Package.swift

 let package = Package(
    name: "Arrow",
    platforms: [
-        .macOS(.v10_15)
+        .macOS(.v10_15),
+        .iOS(.v15)
    ],


Declaring .iOS(.v15) at the package level makes it easy for consumers to expect both Arrow and ArrowFlight to be usable on iOS. Right now the iOS CI job only exercises ArrowTests, so it’s possible for ArrowFlight to drift out of iOS compatibility unnoticed. Consider either (a) expanding iOS CI to compile/build the ArrowFlight product too, or (b) explicitly documenting that iOS support applies only to the core Arrow library if that’s the intent.

jding-xyz added 3 commits March 29, 2026 09:23

feat: Add iOS platform support

a324249

Declare iOS 15+ as a supported platform in Package.swift and document supported platforms in README.md. Made-with: Cursor

chore: Migrate test data to SwiftPM bundle resources

2bf4daa

Replace #file-based currentDirectory() with Bundle.module resource loading for cross-platform compatibility. Write tests now use the system temporary directory instead of the source tree. Made-with: Cursor

chore: Add iOS CI job

2d0552e

Add xcodebuild test job on macos-15 runner with dynamic simulator selection for resilience against runner image updates. Made-with: Cursor

kou requested a review from Copilot March 30, 2026 00:44

Copilot started reviewing on behalf of kou March 30, 2026 00:44 View session

Copilot AI reviewed Mar 30, 2026

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kou reviewed Mar 30, 2026

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jding-xyz force-pushed the feat/ios-support branch from ad7fb9c to 7341ee5 Compare March 30, 2026 05:05

kou requested a review from Copilot March 30, 2026 06:12

Copilot started reviewing on behalf of kou March 30, 2026 06:12 View session

Copilot AI reviewed Mar 30, 2026

View reviewed changes

		fatalError("Test data file \(filename).arrow not found in bundle. "
		+ "Run the Go data generator first.")

		Tests/ArrowTests/*.arrow
		data-generator/swift-datagen/*.arrow

		"Test data file \(filename).arrow not found in bundle. "
		+ "Run the Go data generator first."

-            "Test data file \(filename).arrow not found in bundle. "
-                + "Run the Go data generator first."
+            "Test data file \(filename).arrow not found in test bundle. "
+                + "Verify that the .arrow test resources are correctly declared in Package.swift, "
+                + "and run the Go data generator only when regenerating or updating the committed test data."

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jding-xyz commented Mar 29, 2026 •

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