Simplify env.fish

[kkebo]

Summary

The current env.fish feels a bit complicated. I refactored it with fish's built-in commands.

The fish_add_path options I used:

• -m: Move already-included directories to the place they would be added - by default they would be left in place and not added again.
• -p (default): Add directories to the front of the variable (this is the default).
• -P: Manipulate $PATH directly.

refs: https://fishshell.com/docs/current/cmds/fish_add_path.html

Test

I tested the generated env.fish locally with several PATH configurations, including cases where SWIFTLY_BIN_DIR is absent, already at the beginning, in the middle, or appears multiple times. I didn't commit this test since it's too platform-dependent and requires that all shells are installed.

    @Test(
        .testHome(),
        arguments: ["/bin/bash", "/bin/zsh", "/bin/fish"],
        [
            (
                path: ["/foo", "/bar"],
                expectedPath: ["/swiftly/bin", "/foo", "/bar"]
            ),
            (
                path: ["/swiftly/bin", "/foo", "/bar"],
                expectedPath: ["/swiftly/bin", "/foo", "/bar"]
            ),
            (
                path: ["/foo", "/swiftly/bin", "/bar"],
                expectedPath: ["/swiftly/bin", "/foo", "/bar"]
            ),
            (
                path: ["/foo", "/swiftly/bin", "/bar", "/swiftly/bin"],
                expectedPath: ["/swiftly/bin", "/foo", "/bar"]
            ),
        ]
    )
    func envPrependsSwiftlyBinDirAndRemovesDuplicates(
        shell: String,
        pathCase: (path: [String], expectedPath: [String])
    ) async throws {
        // GIVEN: a fresh user account without swiftly installed
        try? await fs.remove(atPath: Swiftly.currentPlatform.swiftlyConfigFile(SwiftlyTests.ctx))

        // AND: the user is using the bash shell
        var ctx = SwiftlyTests.ctx
        ctx.mockedShell = shell

        try await SwiftlyTests.$ctx.withValue(ctx) {
            let envScript: FilePath?
            if shell.hasSuffix("bash") || shell.hasSuffix("zsh") {
                envScript = Swiftly.currentPlatform.swiftlyHomeDir(SwiftlyTests.ctx) / "env.sh"
            } else if shell.hasSuffix("fish") {
                envScript = Swiftly.currentPlatform.swiftlyHomeDir(SwiftlyTests.ctx) / "env.fish"
            } else {
                envScript = nil
            }

            if let envScript {
                #expect(!(try await fs.exists(atPath: envScript)))
            }

            // WHEN: swiftly is invoked to init the user account and finish swiftly installation
            try await SwiftlyTests.runCommand(Init.self, ["init", "--assume-yes", "--skip-install"])

            // THEN: env script modifies $PATH correctly
            let swiftlyHomeDir = Swiftly.currentPlatform.swiftlyHomeDir(SwiftlyTests.ctx)
            let swiftlyBinDir = Swiftly.currentPlatform.swiftlyBinDir(SwiftlyTests.ctx)

            func replaceSwiftlyBinDir(in path: [String]) -> [String] {
                path.map { $0 == "/swiftly/bin" ? swiftlyBinDir.string : $0 }
            }

            let inputPath = replaceSwiftlyBinDir(in: pathCase.path)
            let expectedPath = replaceSwiftlyBinDir(in: pathCase.expectedPath)

            if let envScript {
                let command = if shell.hasSuffix("fish") {
                    """
                    set -gx PATH \(inputPath.joined(separator: " "))
                    source \(envScript.string)
                    string join : $PATH
                    """
                } else {
                    """
                    PATH='\(inputPath.joined(separator: ":"))'
                    . '\(envScript.string)'
                    printf '%s' "$PATH"
                    """
                }

                let result = try await Subprocess.run(
                    .path(FilePath(shell)),
                    arguments: ["-c", command],
                    output: .string(limit: 1024)
                )

                #expect(result.terminationStatus.isSuccess)

                let actualPath = result.standardOutput?
                    .replacing(/\n$/, with: "")
                    .split(separator: ":")
                    .map(String.init)

                #expect(actualPath == expectedPath)
            }
        }
    }

$ swift test --filter InitTests.envPrependsSwiftlyBinDirAndRemovesDuplicates
...
✔ Test envPrependsSwiftlyBinDirAndRemovesDuplicates(shell:pathCase:) with 12 test cases passed after 0.190 seconds.
✔ Suite InitTests passed after 0.191 seconds.
✔ Test run with 1 test in 1 suite passed after 0.191 seconds.

Environment:

$ uname -a
Linux Raspberry-beetle 6.18.34+rpt-rpi-2712 #1 SMP PREEMPT Debian 1:6.18.34-1+rpt1 (2026-06-09) aarch64 GNU/Linux
$ fish --version
fish, version 4.8.0
$ zsh --version
zsh 5.9 (aarch64-unknown-linux-gnu)
$ bash --version
GNU bash, version 5.2.37(1)-release (aarch64-unknown-linux-gnu)
Copyright (C) 2022 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>

This is free software; you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

[kkebo]

I understand that my script is not equivalent to the old one with the following test.

    @Test(
        .testHome(),
        arguments: ["/bin/bash", "/bin/zsh", "/bin/fish"],
        [
            (
                path: ["/foo", "/bar"],
                expectedPath: ["/swiftly/bin", "/foo", "/bar"]
            ),
            (
                path: ["/swiftly/bin", "/foo", "/bar"],
                expectedPath: ["/swiftly/bin", "/foo", "/bar"]
            ),
            (
                path: ["/foo", "/swiftly/bin", "/bar"],
                expectedPath: ["/swiftly/bin", "/foo", "/bar"]
            ),
            (
                path: ["/foo", "/swiftly/bin", "/bar", "/swiftly/bin"],
                expectedPath: ["/swiftly/bin", "/foo", "/bar"]
            ),
        ]
    )
    func envPrependsSwiftlyBinDirAndRemovesDuplicates(
        shell: String,
        pathCase: (path: [String], expectedPath: [String])
    ) async throws {
        // GIVEN: a fresh user account without swiftly installed
        try? await fs.remove(atPath: Swiftly.currentPlatform.swiftlyConfigFile(SwiftlyTests.ctx))

        // AND: the user is using the bash shell
        var ctx = SwiftlyTests.ctx
        ctx.mockedShell = shell

        try await SwiftlyTests.$ctx.withValue(ctx) {
            let envScript: FilePath?
            if shell.hasSuffix("bash") || shell.hasSuffix("zsh") {
                envScript = Swiftly.currentPlatform.swiftlyHomeDir(SwiftlyTests.ctx) / "env.sh"
            } else if shell.hasSuffix("fish") {
                envScript = Swiftly.currentPlatform.swiftlyHomeDir(SwiftlyTests.ctx) / "env.fish"
            } else {
                envScript = nil
            }

            if let envScript {
                #expect(!(try await fs.exists(atPath: envScript)))
            }

            // WHEN: swiftly is invoked to init the user account and finish swiftly installation
            try await SwiftlyTests.runCommand(Init.self, ["init", "--assume-yes", "--skip-install"])

            // THEN: env script modifies $PATH correctly
            let swiftlyHomeDir = Swiftly.currentPlatform.swiftlyHomeDir(SwiftlyTests.ctx)
            let swiftlyBinDir = Swiftly.currentPlatform.swiftlyBinDir(SwiftlyTests.ctx)

            func replaceSwiftlyBinDir(in path: [String]) -> [String] {
                path.map { $0 == "/swiftly/bin" ? swiftlyBinDir.string : $0 }
            }

            let inputPath = replaceSwiftlyBinDir(in: pathCase.path)
            let expectedPath = replaceSwiftlyBinDir(in: pathCase.expectedPath)

            if let envScript {
                let command = if shell.hasSuffix("fish") {
                    """
                    set -gx PATH \(inputPath.joined(separator: " "))
                    source \(envScript.string)
                    string join : $PATH
                    """
                } else {
                    """
                    PATH='\(inputPath.joined(separator: ":"))'
                    . '\(envScript.string)'
                    printf '%s' "$PATH"
                    """
                }

                let result = try await Subprocess.run(
                    .path(FilePath(shell)),
                    arguments: ["-c", command],
                    output: .string(limit: 1024)
                )

                #expect(result.terminationStatus.isSuccess)

                let actualPath = result.standardOutput?
                    .replacing(/\n$/, with: "")
                    .split(separator: ":")
                    .map(String.init)

                #expect(actualPath == expectedPath)
            }
        }
    }

$ swift test --filter InitTests.envPrependsSwiftlyBinDirAndRemovesDuplicates
...
✘ Test envPrependsSwiftlyBinDirAndRemovesDuplicates(shell:pathCase:) recorded an issue with 2 arguments shell → "/bin/fish", pathCase → (path: ["/foo", "/swiftly/bin", "/bar", "/swiftly/bin"], expectedPath: ["/swiftly/bin", "/foo", "/bar"]) at InitTests.swift:217:17: Expectation failed: (actualPath → ["/tmp/swiftly-tests-testHome-3D0FC3FE-2A7A-4D3A-898B-2F26120A3FF6/bin", "/foo", "/bar", "/tmp/swiftly-tests-testHome-3D0FC3FE-2A7A-4D3A-898B-2F26120A3FF6/bin"]) == (expectedPath → ["/tmp/swiftly-tests-testHome-3D0FC3FE-2A7A-4D3A-898B-2F26120A3FF6/bin", "/foo", "/bar"])
✘ Test envPrependsSwiftlyBinDirAndRemovesDuplicates(shell:pathCase:) with 12 test cases failed after 0.185 seconds with 1 issue.
✘ Suite InitTests failed after 0.186 seconds with 1 issue.
✘ Test run with 1 test in 1 suite failed after 0.186 seconds with 1 issue.

This is because fish_add_path -mP does not remove all existing duplicates.

[kkebo]

Fixed: 881c1ac (this PR)

[kkebo]

I tested the generated env.fish locally with several PATH configurations, including cases where SWIFTLY_BIN_DIR is absent, already at the beginning, in the middle, or appears multiple times. The behavior was unchanged with this refactoring. I didn't commit this test since it's too platform-dependent and requires that all shells are installed.

    @Test(
        .testHome(),
        arguments: ["/bin/bash", "/bin/zsh", "/bin/fish"],
        [
            (
                path: ["/foo", "/bar"],
                expectedPath: ["/swiftly/bin", "/foo", "/bar"]
            ),
            (
                path: ["/swiftly/bin", "/foo", "/bar"],
                expectedPath: ["/swiftly/bin", "/foo", "/bar"]
            ),
            (
                path: ["/foo", "/swiftly/bin", "/bar"],
                expectedPath: ["/swiftly/bin", "/foo", "/bar"]
            ),
            (
                path: ["/foo", "/swiftly/bin", "/bar", "/swiftly/bin"],
                expectedPath: ["/swiftly/bin", "/foo", "/bar"]
            ),
        ]
    )
    func envPrependsSwiftlyBinDirAndRemovesDuplicates(
        shell: String,
        pathCase: (path: [String], expectedPath: [String])
    ) async throws {
        // GIVEN: a fresh user account without swiftly installed
        try? await fs.remove(atPath: Swiftly.currentPlatform.swiftlyConfigFile(SwiftlyTests.ctx))

        // AND: the user is using the bash shell
        var ctx = SwiftlyTests.ctx
        ctx.mockedShell = shell

        try await SwiftlyTests.$ctx.withValue(ctx) {
            let envScript: FilePath?
            if shell.hasSuffix("bash") || shell.hasSuffix("zsh") {
                envScript = Swiftly.currentPlatform.swiftlyHomeDir(SwiftlyTests.ctx) / "env.sh"
            } else if shell.hasSuffix("fish") {
                envScript = Swiftly.currentPlatform.swiftlyHomeDir(SwiftlyTests.ctx) / "env.fish"
            } else {
                envScript = nil
            }

            if let envScript {
                #expect(!(try await fs.exists(atPath: envScript)))
            }

            // WHEN: swiftly is invoked to init the user account and finish swiftly installation
            try await SwiftlyTests.runCommand(Init.self, ["init", "--assume-yes", "--skip-install"])

            // THEN: env script modifies $PATH correctly
            let swiftlyHomeDir = Swiftly.currentPlatform.swiftlyHomeDir(SwiftlyTests.ctx)
            let swiftlyBinDir = Swiftly.currentPlatform.swiftlyBinDir(SwiftlyTests.ctx)

            func replaceSwiftlyBinDir(in path: [String]) -> [String] {
                path.map { $0 == "/swiftly/bin" ? swiftlyBinDir.string : $0 }
            }

            let inputPath = replaceSwiftlyBinDir(in: pathCase.path)
            let expectedPath = replaceSwiftlyBinDir(in: pathCase.expectedPath)

            if let envScript {
                let command = if shell.hasSuffix("fish") {
                    """
                    set -gx PATH \(inputPath.joined(separator: " "))
                    source \(envScript.string)
                    string join : $PATH
                    """
                } else {
                    """
                    PATH='\(inputPath.joined(separator: ":"))'
                    . '\(envScript.string)'
                    printf '%s' "$PATH"
                    """
                }

                let result = try await Subprocess.run(
                    .path(FilePath(shell)),
                    arguments: ["-c", command],
                    output: .string(limit: 1024)
                )

                #expect(result.terminationStatus.isSuccess)

                let actualPath = result.standardOutput?
                    .replacing(/\n$/, with: "")
                    .split(separator: ":")
                    .map(String.init)

                #expect(actualPath == expectedPath)
            }
        }
    }

$ swift test --filter InitTests.envPrependsSwiftlyBinDirAndRemovesDuplicates
...
✔ Test envPrependsSwiftlyBinDirAndRemovesDuplicates(shell:pathCase:) with 12 test cases passed after 0.190 seconds.
✔ Suite InitTests passed after 0.191 seconds.
✔ Test run with 1 test in 1 suite passed after 0.191 seconds.

Environment:

$ uname -a
Linux Raspberry-beetle 6.18.34+rpt-rpi-2712 #1 SMP PREEMPT Debian 1:6.18.34-1+rpt1 (2026-06-09) aarch64 GNU/Linux
$ fish --version
fish, version 4.8.0
$ zsh --version
zsh 5.9 (aarch64-unknown-linux-gnu)
$ bash --version
GNU bash, version 5.2.37(1)-release (aarch64-unknown-linux-gnu)
Copyright (C) 2022 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>

This is free software; you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

@cmcgee1024 Since you originally worked on this logic, would you mind taking a look when you have a chance? I’d especially appreciate your thoughts on whether there are any edge cases I may have missed.