v0.4.3 crashs when using Transform closure

[griffin-stewie]

It crashes(SIGABRT) on Release build when I use Transform closure.

I tested several versions bellow. Only v0.4.3 has this issue.

• ✅ 0.3.2
• ✅ 0.4.0
• ✅ 0.4.1
• ✅ 0.4.2
• ‼️ 0.4.3
• ‼️ main branch

ArgumentParser version: 0.4.3
Swift version: Apple Swift version 5.4 (swiftlang-1205.0.26.9 clang-1205.0.19.55) Target: x86_64-apple-darwin20.5.0

Checklist

• If possible, I've reproduced the issue using the main branch of this package
• I've searched for existing GitHub issues

Steps to Reproduce

Here is my sample code to reproduce this issue.

1. Build sample code with Release configuration.
2. Run this sample_cal description --start-date 2021/07/18_11:22:33 --name aaa

I suspect that the crash is caused by using @Option(name: , help: , transform: ).

One more thing, It prints a blank where start: Date should be printed, if I deleted @Option() var name: String.

Expected behavior

No crash, and prints OptionGroup’s description.

Actual behavior

Crashed.

Xcode shows some logs on console, like bellow:

sample\_cal(687,0x10026fe00) malloc: Double free of object 0x105a47cc0
sample\_cal(687,0x10026fe00) malloc: \*\*\* set a breakpoint in malloc\_error\_break to debug

[rauhul]

I played around with your sample code in Xcode and on the command line. I tried reducing the example and had a wild amount of non deterministic results based on: clean vs incremental builds, Date vs Int, etc... To me, this screams mis-compile and not library bug. Additionally, one of crashes modes I've seen is an EXC_BAD_ACCESS in the as? operator which is also very suspicious.

Apple Swift version 5.3.1 (swiftlang-1205.0.16.11 clang-1205.0.19.6)
Target: x86_64-apple-darwin20.3.0
SAP: 0.4.3 & ee32b809403dc77bded883194e3bbcb107be5104

[natecook1000]

Thanks for the detailed report, @griffin-stewie!

[griffin-stewie]

Thanks @natecook1000 and @rauhul !

[griffin-stewie]

I've tested my sample code with the latest ArgumentParser v0.4.4. Everything works great!