| Message ID | fec7ef37962da584a89012234ae4a1a@72481c9465c8b2c4aaff8b77ab5e23c (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Eliminate extraneous ref log entries | expand |
"Kyle J. McKay" <mackyle@gmail.com> writes: > The git command `git symbolic-ref <refname1> <refname2>` updates > <refname1> to be a "symbolic" pointer to <refname2>. No matter > what future value <refname2> takes on, <refname1> will continue > to refer to that future value since it's "symbolic". Correct. While you are on the my-topic branch, HEAD (that's the <refname1> in your description) points at refs/heads/my-topic (that's the <refname2> in your description). And when you create a new commit from this state, the logs of these two refs will gain one entry each. "git log HEAD@{now} would show the recent progress of HEAD, "git log my-topic@{now}" would show the recent progress of my-topic ("my-topic@"now}" can also be spelled as "@{now}). The <refname1> (HEAD) will keep referring to <refname2> (my-topic) until you switch branches, and does not change even if <refname2> points at a different commit, as it is "symbolic". > Since commit 523fa69c36744ae6 ("reflog: cleanse messages in the refs.c > layer", 2020-07-10, v2.29.0), the effect of using the aforementioned > "symbolic-ref" command on ref logs has changed in an unexpected way. Please explain "in an unexpected way" here in the log message. Not every reader can read your mind and would expect the same as you do. The said commit came as part of this topic, ... https://lore.kernel.org/git/pull.669.v2.git.1594401593.gitgitgadget@gmail.com/ ... so I've added the true author of it on the Cc: list. > Add a new set of tests to exercise and demonstrate this change > in preparation for correcting it (at which point the failing tests > will be flipped from `test_expect_failure` to `test_expect_success`). We usually prefer not to do the two-step "expect_failure first and then in a separate patch flip that to _success", as it makes it hard to see the "fix" step (because the change in the test would be shown only 3 lines before and after _failure->_success line, and what the test is doing cannot be seen in the patch by itself). Thanks.
On Jan 30, 2021, at 11:56, Junio C Hamano wrote: > The said commit came as part of this topic, ... > > https://lore.kernel.org/git/pull.669.v2.git.1594401593.gitgitgadget@gmail.com/ > > ... so I've added the true author of it on the Cc: list. Out of curiosity, if Han-Wen Nienhuys is the true author of commit 523fa69c36744ae6 why is it that you are both the committer and author of that commit in the commit's header? The answer may also inform others trying to determine the best list of recipients for patches...
On Jan 30, 2021, at 11:56, Junio C Hamano wrote: >> Add a new set of tests to exercise and demonstrate this change >> in preparation for correcting it (at which point the failing tests >> will be flipped from `test_expect_failure` to `test_expect_success`). > > We usually prefer not to do the two-step "expect_failure first and > then in a separate patch flip that to _success", as it makes it hard > to see the "fix" step (because the change in the test would be shown > only 3 lines before and after _failure->_success line, and what the > test is doing cannot be seen in the patch by itself). I'm having a bit of trouble parsing that into expectations. A little help please. Given the scenario that a bug is found that is not being caught by a test (irrespective of whether or not the outcome of this particular series discussion results in it being determined to be a "bug"). Further, if the fix is simple enough that it warrants only a single patch, what is the preferred order of patches then? I would like the patch series to demonstrate: 1) that the test actually catches the bug (in case it comes back in the future) 2) the fix isolated (as much as possible) in a patch distinct from the test 3) that the test now passes, preferably with minimal changes to be sure that it hasn't accidentally been rendered ineffective All the while, at no point after commits for (1), (2), or (3) is the test suite allowed to generate extra failures (that are not marked "expect failure"). patch 1/2 accomplishes (1) patch 2/2 does both (2) and (3) Are you suggesting that (1) just be omitted? Or that it be modified so that it's an "expect success" patch? But then (2) would break it and introduce a failing test into the test suite. Should (2) then just flip the test from test_expect_success to test_expect_failure and then a separate commit flip it back to test_expect_success along with the minor change to the test itself to make it start passing again? In that case, there's always a risk that changing the test itself could accidentally make it no longer detect the problem anymore and just always succeed even if the problem comes back. Without an initial expect_failure step (1), there's no commit in the repository that can demonstrate that the test actually catches the problem. I understand that when new code is added, the tests come after, but it seems to me that when fixing a pre-existing problem, the test that demonstrates the problem should come first and be an expect failure since it is considered to be a problem. What exactly is the order of test/fix changes that you're expecting to see here? Thanks.
"Kyle J. McKay" <mackyle@gmail.com> writes: > On Jan 30, 2021, at 11:56, Junio C Hamano wrote: > >> The said commit came as part of this topic, ... >> >> https://lore.kernel.org/git/pull.669.v2.git.1594401593.gitgitgadget@gmail.com/ >> >> ... so I've added the true author of it on the Cc: list. > > Out of curiosity, if Han-Wen Nienhuys is the true author of commit > 523fa69c36744ae6 why is it that you are both the committer and author > of that commit in the commit's header? See how the e-mail message was formatted in that thread. I just ran "am" on it (which makes me responsible for committing), and the authorship comes from the "From:" that was in the body. I suspect he may have based the patch on some of the "how about doing it like so" suggestions I made during an earlier discussion and wanted to give me credit for the input, but I do not remember the context the patch was originally written in X-<.
"Kyle J. McKay" <mackyle@gmail.com> writes: > I'm having a bit of trouble parsing that into expectations. A little > help please. > Are you suggesting that (1) just be omitted? Or that it be modified > so that it's an "expect success" patch? Neither. The result of applying the current 1/2 and 2/2 on top of, say 'master', would be the shape of the tree you would want to be in. Our preference is just to have it as a single patch, not as "first expect failure and then flip it to expect success while modifying the code". That approach makes the second step harder to review than necessary, because the "git show" output and "format-patch" output from the step would show only very little about the test that changes behaviour. Even with a single patch, if somebody wants a demonstration of what used to be broken without the code modification, it is easy to apply only the test part of the single patch without using the code change to see how it breaks, so "I want to demonstrate the breakage" is not a reason to have it as a separate step. Thanks.
On Sun, Jan 31, 2021 at 12:48 AM Junio C Hamano <gitster@pobox.com> wrote: > > On Jan 30, 2021, at 11:56, Junio C Hamano wrote: > > > >> The said commit came as part of this topic, ... > >> > >> https://lore.kernel.org/git/pull.669.v2.git.1594401593.gitgitgadget@gmail.com/ > >> > >> ... so I've added the true author of it on the Cc: list. > > > > Out of curiosity, if Han-Wen Nienhuys is the true author of commit > > 523fa69c36744ae6 why is it that you are both the committer and author > > of that commit in the commit's header? > > See how the e-mail message was formatted in that thread. I just ran > "am" on it (which makes me responsible for committing), and the > authorship comes from the "From:" that was in the body. I suspect > he may have based the patch on some of the "how about doing it like > so" suggestions I made during an earlier discussion and wanted to > give me credit for the input, but I do not remember the context the > patch was originally written in X-<. The classic reflog format doesn't allow '\n' in messages, but different parts of the code did try to write '\n'. This patch was supposed to sanitize the messages in a central location, so alternate ref backends do not trigger spurious differences in how reflogs are represented. Your patch says > has changed in an unexpected way. Can you make the expectations and current behavior explicit?
diff --git a/t/t1417-reflog-symref.sh b/t/t1417-reflog-symref.sh new file mode 100755 index 00000000..6149531f --- /dev/null +++ b/t/t1417-reflog-symref.sh @@ -0,0 +1,91 @@ +#!/bin/sh +# +# Copyright (c) 2021 Kyle J. McKay +# + +test_description='Test symbolic-ref effects on reflogs' +GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=main +export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME + +. ./test-lib.sh + +test_expect_success setup ' + test_commit 'initial' && + git checkout -b unu && + test_commit 'one' && + git checkout -b du && + test_commit 'two' && + git checkout -b tri && + test_commit 'three' && + git checkout du && + test_commit 'twofour' && + git checkout -b KVAR du && + test_commit 'four' && + unu="$(git rev-parse --verify unu)" && + du="$(git rev-parse --verify du)" && + tri="$(git rev-parse --verify tri)" && + kvar="$(git rev-parse --verify KVAR)" && + test -n "$unu" && + test -n "$du" && + test -n "$tri" && + test -n "$kvar" && + test "$unu" != "$du" && + test "$unu" != "$tri" && + test "$unu" != "$kvar" && + test "$du" != "$tri" && + test "$du" != "$kvar" && + test "$tri" != "$kvar" && + git symbolic-ref refs/heads/KVAR refs/heads/du && + kvarsym="$(git rev-parse --verify KVAR)" && + test "$kvarsym" = "$du" && + test "$kvarsym" != "$kvar" && + git reflog exists HEAD && + git reflog exists refs/heads/KVAR && + git symbolic-ref HEAD >/dev/null && + git symbolic-ref refs/heads/KVAR && + git checkout unu && + hcnt=$(git reflog show HEAD | wc -l) && + kcnt=$(git reflog show refs/heads/KVAR | wc -l) && + test -n "$hcnt" && + test -n "$kcnt" && + test $hcnt -gt 1 && + test $kcnt -gt 1 && + test $hcnt -ne $kcnt +' + +test_expect_failure 'HEAD reflog symbolic-ref' ' + hcnt1=$(git reflog show HEAD | wc -l) && + git symbolic-ref HEAD refs/heads/unu && + git symbolic-ref HEAD refs/heads/du && + git symbolic-ref HEAD refs/heads/tri && + hcnt2=$(git reflog show HEAD | wc -l) && + test $hcnt1 = $hcnt2 +' + +test_expect_failure 'refs/heads/KVAR reflog symbolic-ref' ' + kcnt1=$(git reflog show refs/heads/KVAR | wc -l) && + git symbolic-ref refs/heads/KVAR refs/heads/tri && + git symbolic-ref refs/heads/KVAR refs/heads/du && + git symbolic-ref refs/heads/KVAR refs/heads/unu && + kcnt2=$(git reflog show refs/heads/KVAR | wc -l) && + test $kcnt1 = $kcnt2 +' + +test_expect_failure 'double symref reflog symbolic-ref' ' + hcnt1=$(git reflog show HEAD | wc -l) && + kcnt1=$(git reflog show refs/heads/KVAR | wc -l) && + git symbolic-ref HEAD refs/heads/KVAR && + git symbolic-ref refs/heads/KVAR refs/heads/du && + git symbolic-ref refs/heads/KVAR refs/heads/unu && + git symbolic-ref refs/heads/KVAR refs/heads/tri && + git symbolic-ref HEAD refs/heads/du && + git symbolic-ref HEAD refs/heads/tri && + git symbolic-ref HEAD refs/heads/unu && + hcnt2=$(git reflog show HEAD | wc -l) && + kcnt2=$(git reflog show refs/heads/KVAR | wc -l) && + test $hcnt1 = $hcnt2 && + test $kcnt1 = $kcnt2 && + test $hcnt2 != $kcnt2 +' + +test_done
The git command `git symbolic-ref <refname1> <refname2>` updates <refname1> to be a "symbolic" pointer to <refname2>. No matter what future value <refname2> takes on, <refname1> will continue to refer to that future value since it's "symbolic". Since commit 523fa69c36744ae6 ("reflog: cleanse messages in the refs.c layer", 2020-07-10, v2.29.0), the effect of using the aforementioned "symbolic-ref" command on ref logs has changed in an unexpected way. Add a new set of tests to exercise and demonstrate this change in preparation for correcting it (at which point the failing tests will be flipped from `test_expect_failure` to `test_expect_success`). The new test file can be used unchanged to examine this behavior in much older Git versions (likely to as far back as v2.6.0). Signed-off-by: Kyle J. McKay <mackyle@gmail.com> --- t/t1417-reflog-symref.sh | 91 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 91 insertions(+) create mode 100755 t/t1417-reflog-symref.sh --