Sean Whitton writes ("Re: Bug#1108378: git-debpush: should warn for superfluous
quilt mode option on command line"):
> On Tue 01 Jul 2025 at 02:46pm +01, Ian Jackson wrote:
> > But implementing this may be nontrivial. quilt mode archaeology is
> > complex, and currently it is allowed to crash whenever it can't figure
> > things out. I think this proposal involves distinguishing "something
> > is unexpected about the git structure which means that we cannot
> > determine the quilt mode automatically" from "something is seriously
> > wrong and we should crash even if the user specified --quilt".
>
> Hmm, I think you must have misread my suggestion.
I don't think so. I think I'm just being Dr Error Handling again...
> I just mean that this code:
>
> > # If the user didn't supply a quilt mode, look for it in a previous
> > # tag made by this script
> > if [ "x$quilt_mode" = x ] && [ "$format" = "3.0 (quilt)" ]; then
> > set +o pipefail # perl will SIGPIPE git-cat-file(1) here
> > if [ "x$last_debian_tag" != x ]; then
> > quilt_mode=$(git cat-file -p $(git rev-parse "$last_debian_tag") \
> > | perl -wne'/^\[dgit.*--quilt=([a-z+]+).*\]$/
> > or next;
> > print "$1\n"; exit')
> > fi
> > set -o pipefail
> > fi
>
> should be run even if the user *did* supply a quilt mode, and if they
> are different it's a failed check.
This code can fail due to (for example) the tag named by
last_debian_tag not existing, or having weird syntax.
In that case, if the user supplied --quilt=, that's silently fine: we
failed to check the user's work, but the anomaly is presumably why the
user is passing that option.
To put it in type threory terms in Rust syntax.
Before:
fn determine_quilt_mode_automatically(...)
-> Result<QuiltMode, FatalError>
After:
fn determine_quilt_mode_automatically(...)
-> Rdsult<Result<QuiltMode, CouldNotDetermineQuiltMode>, FatalError>
This means that every program call needs to be considered for whether
failure of this program (or perhpas, *this kind* of failure of this
program) is "expected" (-> CouldNotDetermineQuiltMode, might be
silently ignored) or "unexpedcted" (-> FatalError, always crash).
That is doable but it's not trivial.
Ian.
--
Ian Jackson <ijack...@chiark.greenend.org.uk> These opinions are my own.
Pronouns: they/he. If I emailed you from @fyvzl.net or @evade.org.uk,
that is a private address which bypasses my fierce spamfilter.
