[PATCH] D65697: [lit] Fix internal env calling env

Wed Aug 21 08:29:43 PDT 2019

probinson added a comment.

> Do people know why an internal diff was implemented originally? Is there a portability or performance issue?

See D39567 <https://reviews.llvm.org/D39567> and in particular an enthused zturner looked forward to the day when all "shell" commands are internal, eliminating cross-platform issues and most if not all dependencies on additional packages other than Python (e.g. GnuWin32 on Windows).  The only external commands would be LLVM-built tools/utilities.  I see rnk participated in that review (late 2017).

> If it's worthwhile to have an internal diff, is it worthwhile for it to support everything external diffs do? All pipes and redirects could be replaced by temporary files.

Creating temp files is slower than piping, given we have tens of thousands of tests it feels worthwhile to support piping.  For diff in particular I found only one (I think unnecessary) redirect so not supporting that seems reasonable.

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D65697/new/

https://reviews.llvm.org/D65697