multi-line perl within bash confuses difft

[xkcd386at]

Hi

I have a peculiar case which I have reduced to the following simple example. The summary would be shell script with a multi-line perl invocation inside it, confuses difft.

Note that "old.sh" and "old2.sh" differ only in making the multi-line into a single line. Similarly new.sh and new2.sh. Diffing the single line version does indeed come up with the expected "No syntactic changes" but diffing the multiline version does not.

(Note: I left one blank line before each command for visual clarity).

$ cat old.sh
#!/bin/bash
    out=$(
        perl -lne '
            next unless /\S/;
        ' | fzf -m | cut -f2,5
    )

$ cat new.sh
#!/bin/bash
out=$(
    perl -lne '
        next unless /\S/;
    ' | fzf -m | cut -f2,5
)

$ ./difft --display inline old.sh new.sh
new.sh --- Bash
File permissions changed from 100600 to 100700.
1    #!/bin/bash
2        out=$(
3            perl -lne '
4                next unless /\S/;
5            ' | fzf -m | cut -f2,5
   3     perl -lne '
   4         next unless /\S/;
   5     ' | fzf -m | cut -f2,5
   6 )


$ cat old2.sh
#!/bin/bash
    out=$(
        perl -lne ' next unless /\S/; ' | fzf -m | cut -f2,5
    )

$ cat new2.sh
#!/bin/bash
out=$(
    perl -lne ' next unless /\S/; ' | fzf -m | cut -f2,5
)

$ ./difft --display inline old2.sh new2.sh
new2.sh --- Bash
File permissions changed from 100600 to 100700.
No syntactic changes.