how do i pin the version of swift in my project?

[DetachHead]

i tried using .swift-version but in my CI on macOS it seems to just completely ignore it and change it to the latest version?

.github/workflows/ci.yaml

jobs:
  build-macos:
    runs-on: "macos-latest"
    steps:
      - uses: actions/checkout@v4
      - run: |
          brew install swiftly
          swiftly init
          . "/Users/runner/.swiftly/env.sh"
          swift build

.swift-version

6.2.4

Package.swift

// swift-tools-version: 6.2.4

// ...

github actions output

==> Fetching downloads for: swiftly
✔︎ Bottle Manifest swiftly (1.1.1)
✔︎ Bottle swiftly (1.1.1)
==> Pouring swiftly--1.1.1.arm64_sequoia.bottle.1.tar.gz
🍺  /opt/homebrew/Cellar/swiftly/1.1.1: 10 files, 26.5MB
==> Caveats
Bash completion has been installed to:
  /opt/homebrew/etc/bash_completion.d
Welcome to swiftly, the Swift toolchain manager for Linux and macOS!
Please read the following information carefully before proceeding with the
installation. If you
wish to customize the steps performed during the installation process, refer to
'swiftly init -h'
for configuration options.
Swiftly installs files into the following locations:
/Users/runner/.swiftly - Directory for configuration files
/Users/runner/.swiftly/bin - Links to the binaries of the active toolchain
/Users/runner/Library/Developer/Toolchains - Directory hosting installed
toolchains
These locations can be changed by setting the environment variables
SWIFTLY_HOME_DIR, SWIFTLY_BIN_DIR, and SWIFTLY_TOOLCHAINS_DIR before running
'swiftly init' again.
Once swiftly is set up, it will install the latest available Swift toolchain.
This can be
suppressed with the '--skip-install' option.
For your convenience, swiftly will also attempt to modify your shell's profile
file to make
installed items available in your environment upon login. This can be suppressed
with the
'--no-modify-profile' option.
Proceed? (Y/n): 
Creating shell environment file for the user...
Updating profile...
Fetching the latest stable Swift release...
Installing Swift 6.3.0
Downloading Swift 6.3.0
0%: Downloaded 0.7 MiB of 1433.3 MiB
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Installing package in user home directory...
The file `/Users/runner/work/project/project/.swift-version` has been set to `Swift 6.3.0`
The global default toolchain has been set to `Swift 6.3.0`
Swift 6.3.0 is installed successfully!
To begin using installed swiftly from your current shell, first run the
following command:
    
# Added by swiftly
. "/Users/runner/.swiftly/env.sh"
NOTE: Swiftly has updated some elements in your path and your shell may not yet
be
aware of the changes. You can update your shell's environment by running
hash -r
or restarting your shell.

i don't understand why it would change the .swift-version automatically. that seems to defeat the purpose of the .swift-version file

[plemarquand]

It looks like there might be a bug here. swiftly init will install the latest toolchain globally, ignoring .swift-version in the current directory.

To work around this for now you can instead do swiftly init --skip-install followed by a swiftly install to install the toolchain defined in .swift-version.

A question for @cmcgee1024, @etcwilde, @justice-adams-apple: If swiftly init is run in a folder with a .swift-version file should it:

1. Install the latest toolchain globally, don't update .swift-version
2. Install the toolchain defined in .swift-version, don't install a global toolchain
3. Install the toolchain defined in .swift-version, and also install the latest toolchain globally.

I assume the goal with swiftly init is to always have a global toolchain installed when its done, so I'm leaning towards 1 (and require the user to do a swiftly install from their project folder) but 3 might be more convenient.

[etcwilde]

Yeah, updating the .swift-version file while running swiftly init definitely sounds like not intended behavior to me.
1 or 2 sound reasonable to me as well. 3 might be convenient, but would also download a lot of content, which might not be desirable. For CI systems, 2 is probably the most desirable, though they can probably just use --skip-install and do the swiftly install too. If a normal user is in a project directory already and running swiftly init, I think it's a reasonable assumption to make that they are intending to build that project, in which case, they'll also want the version from the .swift-version file, which would also be option 2.

It might also be nice to let swiftly init take a Swift version as an argument (and default to the version .swift-version or latest if not specified) if the user wants to be explicit about their intent.