fatal compiler error on swift 5.7 and Swift 5.8

[sebsto]

Description

using Swift Docc plugin 1.0.0, I receive fatal compilation error from Swift on 5.7 and 5.8

19:03:38 [2/2] Compiling plugin Swift-DocC
19:03:38 error: fatalError

or

19:01:05 Compiling plugin Swift-DocC...
19:01:05 error: emit-module command failed with exit code 1 (use -v to see invocation)
19:01:05 /code/.build/checkouts/swift-docc-plugin/Plugins/Swift-DocC Convert/Symbolic Links/SwiftDocCPluginUtilities/CommandLineArguments/CommandLineArguments.swift:31:50: error: consecutive declarations on a line must be separated by ';'
19:01:05     private var remainingOptionsOrFlags: [String].SubSequence
19:01:05                                                  ^
19:01:05                                                  ;
19:01:05 /code/.build/checkouts/swift-docc-plugin/Plugins/Swift-DocC Convert/Symbolic Links/SwiftDocCPluginUtilities/CommandLineArguments/CommandLineArguments.swift:31:50: error: expected declaration
19:01:05     private var remainingOptionsOrFlags: [String].SubSequence
19:01:05                                                  ^
19:01:05 /code/.build/checkouts/swift-docc-plugin/Plugins/Swift-DocC Convert/Symbolic Links/SwiftDocCPluginUtilities/CommandLineArguments/CommandLineArguments.swift:12:15: note: in declaration of 'CommandLineArguments'
19:01:05 public struct CommandLineArguments {
19:01:05               ^
19:01:05 /code/.build/checkouts/swift-docc-plugin/Plugins/Swift-DocC Convert/Symbolic Links/SwiftDocCPluginUtilities/CommandLineArguments/CommandLineArguments.swift:34:40: error: consecutive declarations on a line must be separated by ';'
19:01:05     private var literalValues: [String].SubSequence
19:01:05                                        ^
19:01:05                                        ;
19:01:05 /code/.build/checkouts/swift-docc-plugin/Plugins/Swift-DocC Convert/Symbolic Links/SwiftDocCPluginUtilities/CommandLineArguments/CommandLineArguments.swift:34:40: error: expected declaration
19:01:05     private var literalValues: [String].SubSequence
19:01:05                                        ^
19:01:05 /code/.build/checkouts/swift-docc-plugin/Plugins/Swift-DocC Convert/Symbolic Links/SwiftDocCPluginUtilities/CommandLineArguments/CommandLineArguments.swift:12:15: note: in declaration of 'CommandLineArguments'
19:01:05 public struct CommandLineArguments {
19:01:05               ^
19:01:05 error: fatalError

This breaks our pipeline for The Swift Lambda runtime, see the automated tests for this PR : swift-server/swift-aws-lambda-runtime#342

Checklist

• If possible, I've reproduced the issue using the main branch of this package.
• This issue hasn't been addressed in an existing GitHub issue.

Expected Behavior

Should compile on last 3 Swift versions

Actual behavior

error: fatalError

Steps To Reproduce

Checkout this PR and compile with a 5.7 or 5.8 toolchain

Swift-DocC Version Information

1.0.0

Swift Compiler Version Information

5.7 and 5.8

[d-ronnqvist]

Did you mean version 1.4.x of the plugin? Version 1.0.0 doesn't have the code that's referenced in that log output.

Assuming so, you can workaround this error by pinning your swift-docc-plugin dependency to 1.3.0

[d-ronnqvist]

I'm on vacation next week, away from a computer, but I can look at this when I get back if no one else has fixed this by then.

[sebsto]

Yes, I tried with version 1.0.0 and 1.3.0 of the plugin. both generates fatal errors when trying to compile with swift 5.7 or Swift 5.8

[d-ronnqvist]

That makes no sense since the file that those errors are about is 1 day old and the 1.3.0 release is from June 2023

[sebsto]

Here is the PR where I observed the error. It looks like the latest version is picked up because of the from

The Package@swift-5.7.swift, Package@swift-5.8.swift, and Package.swift,
have all this dependency

.package(url: "https://github.com/apple/swift-docc-plugin", from: "1.3.0")

This is the error from Jenkins logs for Swift 5.7

Compiling plugin Swift-DocC...
19:59:10 error: emit-module command failed with exit code 1 (use -v to see invocation)
19:59:10 /code/.build/checkouts/swift-docc-plugin/Plugins/Swift-DocC Convert/Symbolic Links/SwiftDocCPluginUtilities/CommandLineArguments/CommandLineArguments.swift:31:50: error: consecutive declarations on a line must be separated by ';'
19:59:10     private var remainingOptionsOrFlags: [String].SubSequence
19:59:10                                                  ^
19:59:10                                                  ;
19:59:10 /code/.build/checkouts/swift-docc-plugin/Plugins/Swift-DocC Convert/Symbolic Links/SwiftDocCPluginUtilities/CommandLineArguments/CommandLineArguments.swift:31:50: error: expected declaration
19:59:10     private var remainingOptionsOrFlags: [String].SubSequence
19:59:10                                                  ^
19:59:10 /code/.build/checkouts/swift-docc-plugin/Plugins/Swift-DocC Convert/Symbolic Links/SwiftDocCPluginUtilities/CommandLineArguments/CommandLineArguments.swift:12:15: note: in declaration of 'CommandLineArguments'
19:59:10 public struct CommandLineArguments {
19:59:10               ^
19:59:10 /code/.build/checkouts/swift-docc-plugin/Plugins/Swift-DocC Convert/Symbolic Links/SwiftDocCPluginUtilities/CommandLineArguments/CommandLineArguments.swift:34:40: error: consecutive declarations on a line must be separated by ';'
19:59:10     private var literalValues: [String].SubSequence
19:59:10                                        ^
19:59:10                                        ;
19:59:10 /code/.build/checkouts/swift-docc-plugin/Plugins/Swift-DocC Convert/Symbolic Links/SwiftDocCPluginUtilities/CommandLineArguments/CommandLineArguments.swift:34:40: error: expected declaration
19:59:10     private var literalValues: [String].SubSequence
19:59:10                                        ^
19:59:10 /code/.build/checkouts/swift-docc-plugin/Plugins/Swift-DocC Convert/Symbolic Links/SwiftDocCPluginUtilities/CommandLineArguments/CommandLineArguments.swift:12:15: note: in declaration of 'CommandLineArguments'
19:59:10 public struct CommandLineArguments {
19:59:10               ^
19:59:10 error: fatalError

This is the error from Jenkins logs for Swift 5.8

19:59:21 [2/2] Compiling plugin Swift-DocC
19:59:21 error: fatalError

I'll force using the 1.3.0 version and report back

[sebsto]

My bad, SPM was picking up the latest version (1.4.1) - I forced the exact 1.3.0 version and this solves the problem.
I updated the original description to mention plugin version 1.4.1

[Kyle-Ye]

I'm on vacation next week, away from a computer, but I can look at this when I get back if no one else has fixed this by then.

I can help fix it. But I think besides it, we need to add some CI check for each PR.

Since the Package.swift is 5.6. We need to add a CI to check build success from 5.6 to 6.0 and main.

Background:
swift-docc has updated Package.swift to 5.9 recently
swift-markdown has updated Package.swift to 5.7 recently
swift-docc-symbolkit which this repo depends has not changed Package.swift yet and still support Swift 5.5+
Maybe we can consider updating Package.swift version to reduce the maintenance cost of CI job.

But sadly GitHub actions are disabled by default in org scope and we need to enable it for this repo or add the CI on ci.swift.org which I do not have permission to contribute.

See related issue and reply here