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

[Joel E. Denny via Phabricator via llvm-commits]

jdenny added a comment.

In D65697#1638038 <https://reviews.llvm.org/D65697#1638038>, @probinson wrote:

> In D65697#1638018 <https://reviews.llvm.org/D65697#1638018>, @probinson wrote:
>
> > I found one example of redirecting diff's output (to /dev/null).
>
>
> This one is in llvm/test/tools/llvm-cov/llvm-cov.test (line 91): `blah | not diff -u somefile - >/dev/null` which IMO could use `-q` and not redirect.


Agreed.  Interestingly, discarding the output makes `-u` pointless, but there's a fixme saying the diff failure here isn't actually desirable.

> But if we make `diff` always be external, it doesn't matter.

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

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.


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https://reviews.llvm.org/D65697