`dhall diff` prints "…" when there is no difference

[sjakobi]

$ dhall diff "1" "1"
…

This seems to suggest that there is some difference where there is none.

I think it would be better to output nothing it all – that's what e.g. GNU diff does, too.

[sjakobi]

Ah, so I think my confusion is related to … being used both for equal expressions and for irrelevant bits as in

$ dhall diff "1" "[] : List Bool"
- 1
+ [ … ] : …

Maybe it would be better to use different symbols for these two things.

[Profpatsch]

It could be good to mirror the behavior of diff(1) here, don’t print output when there is no difference, status code 0 (status 1 if there is a difference).

[Gabriella439]

I think it's more consistent to output … (or whatever symbol we use to denote two things which do not differ) when the two expressions are identical. This is because we output the same placeholder for identical sub-expressions:

$ dhall diff '[ 1 ]' '[ 1, 2 ]'
[ …
, + 2
]

... so it seems odd to me to make an exception for the top-level expression.

However, I agree that the exit code should be 1 if the expressions differ.