[bug-gawk] gawk Regression: CR characters are not stripped on Windows

[arnold@skeeve.com]

Is there a way to distinguish cygwin from msys at compile time?
I would not object to restoring the behavior for msys only.

Thanks,

Arnold

Orgad Shaneh <orgads@gmail.com> wrote:

> Hi,
>
> Cross-posting per Eli Zaretskii's request.
>
> CR characters used to be automatically stripped on Windows (MSYS2 and
> Cygwin environments). This is broken in 4.2.0.
>
> Minimal example:
> echo -en "foo\r\n\r\nbar\r\n" > foo.txt
> awk '/^$/ { print "found" }' foo.txt # This worked with 4.1.4 and
> doesn't work with 4.2.0
> awk '/^\r$/ { print "found" }' foo.txt # This works with 4.2.0 and
> doesn't work with 4.1.4
>
> Bisected to commit 5db38f775d9ba239e125d81dff2010a2ddacb48e:
> (* gawkmisc.c (cygwin_premain0, cygwin_premain2): Remove.
> No longer needed).
>
> Apparently it's still needed...
>
> This issue was reported in https://github.com/git-for-windows/git/issues/1524
>
> Proposed patch is attached.
>
> As Eli said, this change was deliberate. But this has several drawbacks.
>
> 1. The gawk info page states that:
>
> > Under MS-Windows, 'gawk' (and many other text programs) silently
> > translates end-of-line '\r\n' to '\n' on input and '\n' to '\r\n' on
> > output.
>
> and on Feb 8 the following section was added:
>
> > Recent versions of Cygwin open all files in binary mode.  This means
> > that you should use 'RS = "\r?\n"' in order to be able to handle
> > standard MS-Windows text files with carriage-return plus line-feed line
> > endings.
>
> This breaks compatibility between different gawk versions. What were
> the reasons for this change in cygwin, and why was it pushed upstream?
>
> 2. Git and other tools automatically convert text files to CRLF on
> Windows. This means that any awk script that runs on both platforms
> must use RS = "\r?\n". One example that was broken by this behavior
> change is gerrit's commit-msg hook[1], which scans for empty lines by
> /^$/ regexp.
>
> Please consider reverting this change. Patch attached.
>
> [1] https://gerrit.googlesource.com/gerrit/+/376a7bbb64f1b3f13c261f4efa0af0e8538cfe9b/resources/com/google/gerrit/server/tools/root/hooks/commit-msg#101
>
> - Orgad

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