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Track the adoption of Swift 6 strict concurrency checks for data race safety. How many packages are Ready for Swift 6?

Build Information

Failed to build Gnuplot, reference main (1cb0f7), with Swift 6.1 for Linux on 26 Apr 2025 18:23:29 UTC.

Build Command

bash -c docker run --pull=always --rm -v "checkouts-4609320-0":/host -w "$PWD" registry.gitlab.com/finestructure/spi-images:basic-6.1-latest swift build --triple x86_64-unknown-linux-gnu 2>&1

Build Log

========================================
RunAll
========================================
Builder version: 4.61.0
Interrupt handler set up.
========================================
Checkout
========================================
Clone URL: https://github.com/damuellen/Gnuplot.swift.git
Reference: main
Initialized empty Git repository in /host/spi-builder-workspace/.git/
hint: Using 'master' as the name for the initial branch. This default branch name
hint: is subject to change. To configure the initial branch name to use in all
hint: of your new repositories, which will suppress this warning, call:
hint:
hint: 	git config --global init.defaultBranch <name>
hint:
hint: Names commonly chosen instead of 'master' are 'main', 'trunk' and
hint: 'development'. The just-created branch can be renamed via this command:
hint:
hint: 	git branch -m <name>
From https://github.com/damuellen/Gnuplot.swift
 * branch            main       -> FETCH_HEAD
 * [new branch]      main       -> origin/main
HEAD is now at 1cb0f7f Update Gnuplot.swift
Cloned https://github.com/damuellen/Gnuplot.swift.git
Revision (git rev-parse @):
1cb0f7feb96742e9b826880b0d87a47138015c1a
SUCCESS checkout https://github.com/damuellen/Gnuplot.swift.git at main
========================================
Build
========================================
Selected platform:         linux
Swift version:             6.1
Building package at path:  $PWD
https://github.com/damuellen/Gnuplot.swift.git
https://github.com/damuellen/Gnuplot.swift.git
WARNING: environment variable SUPPRESS_SWIFT_6_FLAGS is not set
{
  "dependencies" : [
  ],
  "manifest_display_name" : "Gnuplot",
  "name" : "Gnuplot",
  "path" : "/host/spi-builder-workspace",
  "platforms" : [
  ],
  "products" : [
    {
      "name" : "Gnuplot",
      "targets" : [
        "Gnuplot"
      ],
      "type" : {
        "library" : [
          "automatic"
        ]
      }
    }
  ],
  "targets" : [
    {
      "c99name" : "Gnuplot",
      "module_type" : "SwiftTarget",
      "name" : "Gnuplot",
      "path" : "Sources/Gnuplot",
      "product_memberships" : [
        "Gnuplot"
      ],
      "sources" : [
        "Gnuplot.swift"
      ],
      "type" : "library"
    }
  ],
  "tools_version" : "5.4"
}
Running build ...
bash -c docker run --pull=always --rm -v "checkouts-4609320-0":/host -w "$PWD" registry.gitlab.com/finestructure/spi-images:basic-6.1-latest swift build --triple x86_64-unknown-linux-gnu -Xswiftc -Xfrontend -Xswiftc -stats-output-dir -Xswiftc -Xfrontend -Xswiftc .stats -Xswiftc -strict-concurrency=complete -Xswiftc -enable-upcoming-feature -Xswiftc StrictConcurrency -Xswiftc -enable-upcoming-feature -Xswiftc DisableOutwardActorInference -Xswiftc -enable-upcoming-feature -Xswiftc GlobalActorIsolatedTypesUsability -Xswiftc -enable-upcoming-feature -Xswiftc InferSendableFromCaptures 2>&1
basic-6.1-latest: Pulling from finestructure/spi-images
Digest: sha256:3bdcac04179f4ed3e5b8e9dbd6e74bbf5ebc0f4fde48bbaad7d1e5c757e65bcb
Status: Image is up to date for registry.gitlab.com/finestructure/spi-images:basic-6.1-latest
Building for debugging...
[0/2] Write sources
[1/2] Write swift-version-24593BA9C3E375BF.txt
[3/4] Emitting module Gnuplot
/host/spi-builder-workspace/Sources/Gnuplot/Gnuplot.swift:63:22: warning: static property 'running' is not concurrency-safe because it is nonisolated global shared mutable state; this is an error in the Swift 6 language mode
 61 |     }
 62 |   }
 63 |   private static var running: Process?
    |                      |- warning: static property 'running' is not concurrency-safe because it is nonisolated global shared mutable state; this is an error in the Swift 6 language mode
    |                      |- note: convert 'running' to a 'let' constant to make 'Sendable' shared state immutable
    |                      |- note: add '@MainActor' to make static property 'running' part of global actor 'MainActor'
    |                      `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
 64 | #endif
 65 |
[4/4] Compiling Gnuplot Gnuplot.swift
/host/spi-builder-workspace/Sources/Gnuplot/Gnuplot.swift:63:22: warning: static property 'running' is not concurrency-safe because it is nonisolated global shared mutable state; this is an error in the Swift 6 language mode
 61 |     }
 62 |   }
 63 |   private static var running: Process?
    |                      |- warning: static property 'running' is not concurrency-safe because it is nonisolated global shared mutable state; this is an error in the Swift 6 language mode
    |                      |- note: convert 'running' to a 'let' constant to make 'Sendable' shared state immutable
    |                      |- note: add '@MainActor' to make static property 'running' part of global actor 'MainActor'
    |                      `- note: disable concurrency-safety checks if accesses are protected by an external synchronization mechanism
 64 | #endif
 65 |
/host/spi-builder-workspace/Sources/Gnuplot/Gnuplot.swift:87:29: error: cannot assign value of type 'String' to type 'URL'
 85 |     if let process = Gnuplot.running { if process.isRunning { return process } }
 86 |     let gnuplot = Process()
 87 |     gnuplot.executableURL = "/usr/bin/gnuplot"
    |                             `- error: cannot assign value of type 'String' to type 'URL'
 88 |     gnuplot.arguments = ["--persist"]
 89 |     Gnuplot.running = gnuplot
Running build ...
bash -c docker run --pull=always --rm -v "checkouts-4609320-0":/host -w "$PWD" registry.gitlab.com/finestructure/spi-images:basic-6.1-latest swift build --triple x86_64-unknown-linux-gnu 2>&1
basic-6.1-latest: Pulling from finestructure/spi-images
Digest: sha256:3bdcac04179f4ed3e5b8e9dbd6e74bbf5ebc0f4fde48bbaad7d1e5c757e65bcb
Status: Image is up to date for registry.gitlab.com/finestructure/spi-images:basic-6.1-latest
[0/1] Planning build
Building for debugging...
[0/1] Write swift-version-24593BA9C3E375BF.txt
[2/3] Emitting module Gnuplot
[3/3] Compiling Gnuplot Gnuplot.swift
/host/spi-builder-workspace/Sources/Gnuplot/Gnuplot.swift:87:29: error: cannot assign value of type 'String' to type 'URL'
 85 |     if let process = Gnuplot.running { if process.isRunning { return process } }
 86 |     let gnuplot = Process()
 87 |     gnuplot.executableURL = "/usr/bin/gnuplot"
    |                             `- error: cannot assign value of type 'String' to type 'URL'
 88 |     gnuplot.arguments = ["--persist"]
 89 |     Gnuplot.running = gnuplot
BUILD FAILURE 6.1 linux