os: use GetTempPathW for allocTmpDir on Windows#12469
Merged
mitchellh merged 1 commit intoghostty-org:mainfrom Apr 26, 2026
Merged
os: use GetTempPathW for allocTmpDir on Windows#12469mitchellh merged 1 commit intoghostty-org:mainfrom
mitchellh merged 1 commit intoghostty-org:mainfrom
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`allocTmpDir` previously read `%TMP%` via `getenvW` and returned `null` if the variable wasn't set, requiring each caller to to deal with the nullable. Unfortunately, there isn't a platform-neutral default value that makes sense for those cases (i.e. `/tmp` is POSIX-y). We now use `GetTempPathW` on Windows, which is the official way to get this directory: `TMP` → `TEMP` → `USERPROFILE` → `GetWindowsDirectoryW`. With a real system call behind it, the function no longer needs to be nullable: the only remaining failure modes are OOM (propagated) and the syscall itself failing or returning data we can't decode. In those later cases, we use `C:\Windows\Temp` as a fallback, similar to how we use `/tmp` in the POSIX case. The Windows path always allocates so it still must be paired with `freeTmpDir`, which matches the existing contract.
jcollie
approved these changes
Apr 26, 2026
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allocTmpDirpreviously read%TMP%viagetenvWand returnednullif the variable wasn't set, requiring each caller to to deal with the nullable. Unfortunately, there isn't a platform-neutral default value that makes sense for those cases (i.e./tmpis POSIX-y).We now use
GetTempPathWon Windows, which is the official way to get this directory:TMP→TEMP→USERPROFILE→GetWindowsDirectoryW.With a real system call behind it, the function no longer needs to be nullable: the only remaining failure modes are OOM (propagated) and the syscall itself failing or returning data we can't decode. In those later cases, we use
C:\Windows\Tempas a fallback, similar to how we use/tmpin the POSIX case.The Windows path always allocates so it still must be paired with
freeTmpDir, which matches the existing contract.AI Disclosure: I verified the Windows path using Claude and Zig's cross-compilation capabilities because I don't have a Windows environment in which to test this. I do fully understand the code based on my prior life as a Windows game developer though.