Hi Phillip,
On Wed, 7 Jun 2017, Phillip Wood wrote:
> On 01/06/17 13:56, Johannes Schindelin wrote:
> >
> > On Wed, 31 May 2017, Phillip Wood wrote:
> >
> >> From: Phillip Wood <phillip.wood@xxxxxxxxxxxxx>
> >>
> >> Check the console output when using --autostash and the stash applies
> >> cleanly is what we expect. To avoid this test depending on commit and
> >> stash hashes it uses sed to replace them with XXX. The sed script also
> >> replaces carriage returns in the output with '\r' to avoid embedded
> >> '^M's in the expected output files. Unfortunately this means we still
> >> end up with an embedded '^M' in the sed script which may not be
> >> preserved when sending this. The last line of the sed script should be
> >> +s/^M/\\r/g
> >
> > Like Junio pointed out, this sed script would not be portable. To
> > elaborate: there are two major variants of sed out there, GNU sed and BSD
> > sed. Typically GNU sed allows a little more powerful instructions, e.g. \t
> > and \r.
>
> I'm confused by this as my script does not use the escape sequence "\r"
> out of portability concerns. It has a literal carriage return as you get
> from typing Ctrl-Q Ctrl-M in emacs or Ctrl-V Ctrl-M in bash which I
> think should be portable and replaces the carriage returns in git's
> output with the literal string '\r'. I did this so that the expected
> files don't have control characters in them that mess up the display
> when you cat them or read them in an email client
Junio elaborated elsewhere what my main concern is: while a literal
backslash followed by a lower-case r may be unportable, a plain CR byte is
almost certainly unportable.
> > Taking an additional step back, I wonder whether we have to hard-code
> > the commit IDs (or XXX) to begin with. Why not generate the `expect`
> > files with the information at hand? We can simply ask `git rev-parse
> > --short`.
> >
> > For the stash's commit ID, there is no record in the ref space, of
> > course (because it was created with `git stash create`). But I think
> > in this case, it is legitimate to simply grep the output.
>
> That's a good approach to handling the stash hash if we want to generate
> the expected files from the test script
I would strongly favor that, especially since it would make the transition
away from SHA-1 easier rather than more difficult.
> > That way, the test would be precise and resilient.
> >
> > So for example instead of adding the t/t3420/expected-success-am verbatim,
> > you could generate the output via
> >
> > cat >expect <<-EOF
> > $(grep "^Created autostash: [0-9a-f][0-9a-f]*\\$" output)
> > HEAD is now at $(git rev-parse --short HEAD~2) third commit
> > First, rewinding head to replay your work on top of it...
> > Applying: second commit
> > Applying: third commit
> > Applied autostash.
> > EOF
>
> This approach works well for the cases where there aren't control
> characters embedded in git's output, but for the interactive tests there
> are so we'd end up with control characters in the test script which I
> wanted to avoid or doing $(printf '\r'). I steered clear of generating
> the expected file in the test as i) it was more work (both for me
> (rebase --merge has a few commit hashes in it's output) and when the
> script is running) and ii) it's a bit messy to implement given the way
> the tests are structured in a helper function that's called with a
> parameter indicating the type of rebase to test.
>
> I can go ahead with generating the expected files from the script if you
> really want but I wonder if changing the test to generate the sed script
> with printf as below might be a simpler way to mitigate the carriage
> return problem, though it would be less strict than generating the real
> hashes with rev-parse.
>
> --- a/t/t3420-rebase-autostash.sh
> +++ b/t/t3420-rebase-autostash.sh
> @@ -189,6 +189,16 @@ test_expect_success "rebase: noop rebase" '
> git checkout feature-branch
> '
>
> +test_expect_sucess 'rebase: create sed script to sanitize output' '
> + printf "\
> +s/^\(Created autostash: \)[0-9a-f]\{6,\}$/\1XXX/
> +s/^\(HEAD is now at \)[0-9a-f]\{6,\}\( .* commit\)$/\1XXX\2/
> +s/^[0-9a-f]\{6,\}\( .* commit\)$/XXX\1/
> +s/\(detached HEAD \)[0-9a-f]\{6,\}/\1XXX/
> +s/\(could not apply \)[0-9a-f]\{6,\}/\1XXX/g
> +s/\\r/\\r/g" >$TEST_DIRECTORY/t4320/remove-ids.sed
> +'
> +
>
> Let me know what you think,
I'd rather generate the expected output. If there are control characters
to be embedded anywhere, we have good prior art to do that: see the
q_to_nul(), q_to_cr() and q_to_tab() functions in test-lib-functions.
If you still think that it is too daunting, please point me to a branch
(you're on GitHub, right?) and I can try my hand at a PR.
Ciao,
Dscho