Re: [PATCH] Avoid broken Solaris tr

[Ben Walton <bdwalton@gmail.com>]

On Tue, Jun 18, 2013 at 11:31 PM, Junio C Hamano <gitster@pobox.com> wrote:

Sorry for the very slow reply. This got lost in my inbox and I forgot about it.

> Ben Walton <bdwalton@gmail.com> writes:
>
>> Solaris' tr (both /usr/bin/ and /usr/xpg4/bin) fail to handle the case
>> where the first argument is a multi-character set and the second is a
>> single null character.
>
> Almost all the tr invocations look like converting LF to NUL, except
> for two that squash a colon ':', HT and LF all to NUL.  Is Solaris's
> tr fine with the former but not the latter?

In retrospect, this isn't brokenness, just a difference in System V vs
BSD semantics for tr, both of which are allowed by POSIX since the
behaviour in question is specifically unspecified by the standard. The
System V behaviour is to require a 1:1 map between string1 and string2
transformations whereas BSD behaviour (when len(string2) <
len(string1)) is to pad string2 with the last character in string2
until the lengths are equal.

>
>> We make this change globally in t0008-ignores instead of just for the
>> cases where it matters in order to maintain consistency.
>
> I am not suggesting to keep 'tr "\n" "\0"', but just wanted to make
> sure I am reading the first paragraph correctly.  If we are
> rewriting, we should do so consistently.
>
>> +perl -pne 's/^"//; s/\\//; s/"$//; s/\n/\0/g' stdin >stdin0
>
> What is -pne?  Is it the same as -pe?
>
> tr/\n/\0/ (or y/\n/\0/) may be more faithful to the original.
>
>
>> +perl -pne 's/^"//; s/\\//; s/"$//; s/\n/\0/g' expected-default > \
>> +    expected-default0
>
> Ditto.  We may want to give the same script used in the above two
> (and twice again in the later hunk) more descriptive name, e.g.
>
>         broken_c_unquote () {
>                 perl -pe '... that script ...' "$@"
>         }
>
>         broken_c_quote stdin >stdin0
>
> Side note: the script is broken as a generic C-unquote function in
> multiple ways.  It does not work if it has more than one backslash
> quoted characters, it does not understand \t, \b, \015, \\, etc. to
> name two.
>
> But the breakage does not matter for the strings used in the test
> vector.

I've updated the patch and will forward it shortly.

Thanks
-Ben
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