Avoid truncating the path to the test executable on Windows. #724
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On Windows, we get the path to the (current) test executable by calling `GetModuleFileNameW()`. This function has odd behaviour when the input buffer is too short. Rather than returning `false` or `-1` or some such, as you might expect, it returns successfully but truncates the path (and null-terminates while doing so.) The function _does_ set the last error in this case to `ERROR_INSUFFICIENT_BUFFER`, indicating we need a larger buffer. (The error behaviour on Windows XP is different, but we don't support Windows XP. If you decide to add support for Windows XP to Swift Testing, keep this in mind.) So this PR checks for `ERROR_INSUFFICIENT_BUFFER` and loops with a larger buffer, similar to what we do on Darwin.
grynspan
added
bug
grynspan
requested review from
stmontgomery,
dennisweissmann,
briancroom,
SeanROlszewski and
suzannaratcliff
as code owners
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@swift-ci test |
grynspan
commented
Sep 21, 2024
| @@ -46,9 +46,9 @@ func spawnExecutable( | |||
| ) throws -> ProcessID { | |||
| // Darwin and Linux differ in their optionality for the posix_spawn types we | |||
| // use, so use this typealias to paper over the differences. | |||
| #if SWT_TARGET_OS_APPLE | |||
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Drive-by fix: FreeBSD defines these POSIX types as pointers to opaque structs, so they get imported similarly to Darwin (where they're just raw pointers) rather than Linux (where they're actually structures.)
grynspan
commented
Sep 21, 2024
| @@ -16,7 +16,7 @@ extension CommandLine { | |||
| get throws { | |||
| #if os(macOS) | |||
| var result: String? | |||
| var bufferCount = UInt32(1024) | |||
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Drive-by fix to use a named constant.
grynspan
commented
Sep 21, 2024
| @@ -40,7 +40,7 @@ extension CommandLine { | |||
| } | |||
| #elseif os(FreeBSD) | |||
| var mib = [CTL_KERN, KERN_PROC, KERN_PROC_PATHNAME, -1] | |||
| try mib.withUnsafeMutableBufferPointer { mib in | |||
|
@swift-ci test |
grynspan
commented
Sep 21, 2024
| while result == nil { | ||
| result = withUnsafeTemporaryAllocation(of: CChar.self, capacity: Int(bufferCount)) { buffer in |
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Let's consistently set result in the buffer's scope rather than returning it. This saves us a return nil line and will be easier to translate if/when we get non-escaping buffers.
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@swift-ci test |
compnerd
approved these changes
Sep 22, 2024
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Eh, all but one are in the same function, just different platforms. I can live with it. 🙃 |
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On Windows, we get the path to the (current) test executable by calling
GetModuleFileNameW(). This function has odd behaviour when the input buffer is too short. Rather than returningfalseor-1or some such, as you might expect, it returns successfully but truncates the path (and null-terminates while doing so.)The function does set the last error in this case to
ERROR_INSUFFICIENT_BUFFER, indicating we need a larger buffer. (The error behaviour on Windows XP is different, but we don't support Windows XP. If you decide to add support for Windows XP to Swift Testing, keep this in mind.)So this PR checks for
ERROR_INSUFFICIENT_BUFFERand loops with a larger buffer, similar to what we do on Darwin.Checklist: