Our existing dash ebuilds pass "--disable-lineno" to the configure script to disable its support for the LINENO variable within scripts. However, LINENO is part of POSIX, https://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html and some scripts expect it to work. It was disabled in bug #527644 to work around upstream bashisms in some configure scripts. And while I'm sure a few of those problems persist, I make the following arguments: * As a user, I choose dash for speed. On a Gentoo system, ./configure scripts are likely the most common place to experience those speedups. Forcing ./configure to re-exec itself with /bin/bash because it can't use LINENO is counterproductive to me. * As a developer, I use dash precisely because I want to find and fix these upstream bugs. Sweeping them under the rug hurts the upstreams that care about portability. * Things are a lot better than they were in 2014 for users of a non-bash /bin/sh. By now, a lot of the bashisms should have been caught, and upstreams are at least familiar with the issue (so they won't reject our bug reports).
There is finally someone working on a new release of autoconf, and this is causing problems: https://lists.gnu.org/archive/html/autoconf/2020-03/msg00022.html The LINENO variable is POSIX: https://pubs.opengroup.org/onlinepubs/009695399/utilities/xcu_chap02.html Please, unbreak dash (or let me do it).
I say we give it a try in ~arch. Please go ahead if nobody else protests in the next few day.
Created attachment 619818 [details] dash-0.5.10.2-r1.ebuild Here's an EAPI=7 ebuild. Please review: this ebuild also drops the gentoo-only "dumb echo" patch that was enabled by default. You can see in bug 337329 that vapier went on a rant against dash and hacked the shell to work around the fact that imagemagick was using an autoconf macro that was missing a call to AS_ECHO. Those are *precisely* the sort of portability problems that people use dash to detect. Dash's upstream behavior is correct according to POSIX, and this patch was never submitted, so we're doomed to have "echo" act weird on Gentoo forever unless we drop it.
(In reply to Michael Orlitzky from comment #3) Yeah, I tried disabling the dumb-echo patch by default. https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=68b674d3521a1e08d57b51270de888bfff0beeac vapier changed the USE flag from "dumb-echo", to "vanilla", which effectively re-enabled the patch by default. https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=1a2e3cf9241bb6fef01d8d5e065e790fc713aa86 I have no objection to dropping the patch entirely. The new ebuild looks good to me.
The bug has been closed via the following commit(s): https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=808dded4f103becf7929562b1ed58046aa63f3f6 commit 808dded4f103becf7929562b1ed58046aa63f3f6 Author: Michael Orlitzky <mjo@gentoo.org> AuthorDate: 2020-03-15 15:34:34 +0000 Commit: Michael Orlitzky <mjo@gentoo.org> CommitDate: 2020-03-15 15:56:02 +0000 app-shells/dash: new revision that more-closely matches upstream. Our dash ebuilds differed from upstream in two ways in the past: we disabled LINENO support with --disable-lineno, and we patched the "echo" command to ignore certain arguments and escape sequences. Disabling LINENO tricks configure scripts into re-executing themselves with bash, which can hide errors for users (good?), but also hides them from developers (bad). The LINENO variable is covered by POSIX, and it's counterintuitive to silently force bash on users who have explicitly set /bin/sh to dash. This new revision therefore re-enables LINENO. This same change (in the context of Debian) was discussed on the autoconf mailing list. The "dumb echo" patch reflects a similar situation. Dash's upstream "echo" implementation differs from the bash implementation, but is correct according to POSIX. This can shed light upon some portability bugs, particularly in autoconf scripts, and the "dumb echo" patch hides some of those bugs from end users. But again, it hides them from the authors as well and thereby perpetuates the portability issues. Since this patch is Gentoo-specific, and hides problems that are better addressed elsewhere, this new revision eliminates it. Closes: https://bugs.gentoo.org/687002 Package-Manager: Portage-2.3.84, Repoman-2.3.20 Signed-off-by: Michael Orlitzky <mjo@gentoo.org> app-shells/dash/dash-0.5.10.2-r1.ebuild | 53 +++++++++++++++++++++++++++++++++ 1 file changed, 53 insertions(+)
