Re: [PATCH v2 3/4] rebase: fix garbled progress display with '-x'

[Johannes Schindelin <Johannes.Schindelin@gmx.de>]

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Hi,

On Tue, 11 Jun 2019, SZEDER Gábor wrote:

> On Tue, Jun 11, 2019 at 01:36:16PM -0700, Junio C Hamano wrote:
> > SZEDER Gábor <szeder.dev@gmail.com> writes:
> >
> > > -Rebasing (1/4)QRebasing (2/4)QRebasing (3/4)QRebasing (4/4)QSuccessfully rebased and updated refs/heads/missing-commit.
> > > +Rebasing (1/4)QRebasing (2/4)QRebasing (3/4)QRebasing (4/4)QQ                                                                                QSuccessfully rebased and updated refs/heads/missing-commit.
> > >  EOF
> >
> > Yuck,
>
> Oh yeah...
>
> >... but I do not see how else/better this test can be written
> > myself, which makes it a double-yuck X-<
>
> Perhaps hiding those spaces behind a helper variable e.g.
> 'dump_term_clear_line=Q<80-spaces>Q' and embedding that in the here
> docs specifying the expected output in these three tests could make it
> ever so slightly less yuck...
>
> > Are we forcing out test to operate under dumb terminal mode and with
> > a known number of columns?
>
> 'test-lib.sh' sets TERM=dumb relatively early on, and in these tests
> we don't use 'test_terminal' to run 'git rebase', so...  yeah.  And
> term_columns() defaults to 80.
>
> However, if the terminal were smart, then we would have to deal with
> ANSI escape suddenly popping up...

And I fear that is *exactly* what makes
https://dev.azure.com/gitgitgadget/git/_build/results?buildId=10539&view=ms.vss-test-web.build-test-results-tab
fail...

You cannot easily see it in that output (probably because of incorrectly
encoded Escape sequences in the `.xml` output), so I'll paste what I see
here, locally, when running `t3404-*.sh -i -V -x`:

-- snip --
[...]
ok 99 - rebase -i respects rebase.missingCommitsCheck = ignore

expecting success:
        test_config rebase.missingCommitsCheck warn &&
        rebase_setup_and_clean missing-commit &&
        set_fake_editor &&
        FAKE_LINES="1 2 3 4" \
                git rebase -i --root 2>actual &&
        test_i18ncmp expect actual &&
        test D = $(git cat-file commit HEAD | sed -ne \$p)

++ test_config rebase.missingCommitsCheck warn
++ config_dir=
++ test rebase.missingCommitsCheck = -C
++ test_when_finished 'test_unconfig  '\''rebase.missingCommitsCheck'\'''
++ test 0 = 0
++ test_cleanup='{ test_unconfig  '\''rebase.missingCommitsCheck'\''
                } && (exit "$eval_ret"); eval_ret=$?; :'
++ git config rebase.missingCommitsCheck warn
++ rebase_setup_and_clean missing-commit
++ test_when_finished '
                git checkout master &&
                test_might_fail git branch -D missing-commit &&
                test_might_fail git rebase --abort
        '
++ test 0 = 0
++ test_cleanup='{
                git checkout master &&
                test_might_fail git branch -D missing-commit &&
                test_might_fail git rebase --abort

                } && (exit "$eval_ret"); eval_ret=$?; { test_unconfig  '\''rebase.missingCommitsCheck'\''
                } && (exit "$eval_ret"); eval_ret=$?; :'
++ git checkout -b missing-commit master
Switched to a new branch 'missing-commit'
++ set_fake_editor
++ write_script fake-editor.sh
++ echo '#!/bin/sh'
++ cat
++ chmod +x fake-editor.sh
+++ pwd
+++ builtin pwd -W
++ test_set_editor 'C:/git-sdk-64/usr/src/git/.git/worktrees/wip/temp-rebase-123/t/trash directory.t3404-rebase-interactive/fake-editor.sh'
++ FAKE_EDITOR='C:/git-sdk-64/usr/src/git/.git/worktrees/wip/temp-rebase-123/t/trash directory.t3404-rebase-interactive/fake-editor.sh'
++ export FAKE_EDITOR
++ EDITOR='"$FAKE_EDITOR"'
++ export EDITOR
++ FAKE_LINES='1 2 3 4'
++ git rebase -i --root
rebase -i script before editing:
pick 6e62bf890e21 A
pick 313fe965c048 B
pick d0f65f2f81ee C
pick 0547e3f1350d D
pick 8f99a4f1fbbd E

rebase -i script after editing:
pick 6e62bf890e21 A
pick 313fe965c048 B
pick d0f65f2f81ee C
pick 0547e3f1350d D
++ test_i18ncmp expect actual
++ test_have_prereq C_LOCALE_OUTPUT
++ save_IFS='
'
++ IFS=,
++ set -- C_LOCALE_OUTPUT
++ IFS='
'
++ total_prereq=0
++ ok_prereq=0
++ missing_prereq=
++ for prerequisite in "$@"
++ case "$prerequisite" in
++ negative_prereq=
++ case " $lazily_tested_prereq " in
++ case " $lazily_testable_prereq " in
++ total_prereq=1
++ case "$satisfied_prereq" in
++ satisfied_this_prereq=t
++ case "$satisfied_this_prereq,$negative_prereq" in
++ ok_prereq=1
++ test 1 = 1
++ test_cmp expect actual
++ GIT_ALLOC_LIMIT=0
++ test-tool cmp expect actual
diff --git a/expect b/actual
index 05fcfcb..9555e34 100644
--- a/expect
+++ b/actual
@@ -6,4 +6,4 @@ To avoid this message, use "drop" to explicitly remove a commit.
 Use 'git config rebase.missingCommitsCheck' to change the level of warnings.
 The possible behaviours are: ignore, warn, error.

-Rebasing (1/4)^MRebasing (2/4)^MRebasing (3/4)^MRebasing (4/4)^M                                                                                ^MSuccessfully rebased and updated refs/heads/missing-commit.
+Rebasing (1/4)^MRebasing (2/4)^MRebasing (3/4)^MRebasing (4/4)^MESC[KSuccessfully rebased and updated refs/heads/missing-commit.
error: last command exited with $?=1
not ok 100 - rebase -i respects rebase.missingCommitsCheck = warn
#
#               test_config rebase.missingCommitsCheck warn &&
#               rebase_setup_and_clean missing-commit &&
#               set_fake_editor &&
#               FAKE_LINES="1 2 3 4" \
#                       git rebase -i --root 2>actual &&
#               test_i18ncmp expect actual &&
#               test D = $(git cat-file commit HEAD | sed -ne \$p)
#
-- snap --

(I copy-pasted this from the output of `less` so that the control sequences can be seen.)

To be utterly honest, I really fail to see a reason why a test case that
purports to verify that `git rebase -i` respects
`rebase.missingCommitsCheck=warn` should fail when the progress is shown in an
unexpected format.

It strikes me as yet another poorly written test case that fails to catch the
intended regressions, instead it catches a bug *in the test case itself* when
legitimate changes are made to the progress code.

Nothing in a test suite is worse than a test that fails (or succeeds) for the
wrong reasons.

To make things even worse, the code that generates that `expect` file is
outside the test case.

Here it is, in its full "glory":

-- snip --
q_to_cr >expect <<EOF
Warning: some commits may have been dropped accidentally.
Dropped commits (newer to older):
 - $(git rev-list --pretty=oneline --abbrev-commit -1 master)
To avoid this message, use "drop" to explicitly remove a commit.

Use 'git config rebase.missingCommitsCheck' to change the level of warnings.
The possible behaviours are: ignore, warn, error.

Rebasing (1/4)QRebasing (2/4)QRebasing (3/4)QRebasing (4/4)QQ                                                                                QSuccessfully rebased and updated refs/heads/missing-commit.
EOF
-- snap --

May I please *strongly* suggest to fix this first? It should

- completely lose that last line,
- be inserted into the test case itself so that e.g. disk full problems are
  caught and logged properly, and
- the `test_i18ncmp expect actual` call in the test case should be replaced
  by something like:

	sed "\$d" <actual >actual-skip-progress &&
	test_i18ncmp expect actual-skip-progress

This should obviously be made as a separate, introductory patch (probably with
a less scathing commit message than my comments above would suggest).

And that would also remove the double-yuck.

Ciao,
Dscho