| Message ID | 82e51a52e20fbe13a5a898a0a2f6dbe1188e3fa3.1642116539.git.steadmon@google.com (mailing list archive) |
|---|---|
| State | Superseded |
| Commit | ebb085e3e468f32f3f714a8c14850cc969226056 |
| Headers | show |
| Series | test-lib: unset trace2 parent envvars | expand |
Josh Steadmon <steadmon@google.com> writes: > This behavior breaks certain tests that examine trace2 output when the > tests run as a child of another git process, such as in `git rebase -x > "make test"`. Well explained. The paragraph makes it clear how easy to trigger and get bitten by this problem. > While we could fix this by unsetting the relevant variables in the > affected tests (currently t0210, t0211, t0212, and t6421), this would > leave other tests vulnerable to similar breakage if new test cases are > added which inspect trace2 output. So fix this in general by unsetting > GIT_TRACE2_PARENT_NAME and GIT_TRACE2_PARENT_SID in test-lib.sh. This probably makes sense, but I wonder how it interacts with a user who runs "cd t && GIT_TRACE2=blah ./t0987-test-this.sh" to trace the entire test script, though. > Reported-by: Emily Shaffer <emilyshaffer@google.com> > Helped-by: Jonathan Tan <jonathantanmy@google.com> > Signed-off-by: Josh Steadmon <steadmon@google.com> > --- > t/test-lib.sh | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/t/test-lib.sh b/t/test-lib.sh > index 0f7a137c7d..e4716b0b86 100644 > --- a/t/test-lib.sh > +++ b/t/test-lib.sh > @@ -449,6 +449,8 @@ unset VISUAL EMAIL LANGUAGE $("$PERL_PATH" -e ' > unset XDG_CACHE_HOME > unset XDG_CONFIG_HOME > unset GITPERLLIB > +unset GIT_TRACE2_PARENT_NAME > +unset GIT_TRACE2_PARENT_SID Hmph. Have you noticed the more generic "We want to unset almost everything that begins with GIT_, other than those selected few that are designed to be used to affect the tests" above the part you touched? I am wondering if we should tweak the list there, instead of special casing these two and these two only. There is a pattern that allows anything that match "^GIT_(other|TRACE|things)", and I suspect that the pattern is way too loose (i.e. it allows any garbage to follow, and by allowing "TRACE", it also catches "TRACE2" because the former is a prefix of the latter), which is a problem.
On 2022.01.13 22:01, Junio C Hamano wrote: > Josh Steadmon <steadmon@google.com> writes: > > > This behavior breaks certain tests that examine trace2 output when the > > tests run as a child of another git process, such as in `git rebase -x > > "make test"`. > > Well explained. The paragraph makes it clear how easy to trigger > and get bitten by this problem. > > > While we could fix this by unsetting the relevant variables in the > > affected tests (currently t0210, t0211, t0212, and t6421), this would > > leave other tests vulnerable to similar breakage if new test cases are > > added which inspect trace2 output. So fix this in general by unsetting > > GIT_TRACE2_PARENT_NAME and GIT_TRACE2_PARENT_SID in test-lib.sh. > > This probably makes sense, but I wonder how it interacts with a user > who runs "cd t && GIT_TRACE2=blah ./t0987-test-this.sh" to trace the > entire test script, though. There shouldn't be any problems with this specific use case. I don't see a valid reason for a test runner to fake GIT_TRACE2_PARENT_{NAME,SID} though. None of the TRACE2 modes require using any of the PARENT variables. > > Reported-by: Emily Shaffer <emilyshaffer@google.com> > > Helped-by: Jonathan Tan <jonathantanmy@google.com> > > Signed-off-by: Josh Steadmon <steadmon@google.com> > > --- > > t/test-lib.sh | 2 ++ > > 1 file changed, 2 insertions(+) > > > > diff --git a/t/test-lib.sh b/t/test-lib.sh > > index 0f7a137c7d..e4716b0b86 100644 > > --- a/t/test-lib.sh > > +++ b/t/test-lib.sh > > @@ -449,6 +449,8 @@ unset VISUAL EMAIL LANGUAGE $("$PERL_PATH" -e ' > > unset XDG_CACHE_HOME > > unset XDG_CONFIG_HOME > > unset GITPERLLIB > > +unset GIT_TRACE2_PARENT_NAME > > +unset GIT_TRACE2_PARENT_SID > > Hmph. Have you noticed the more generic "We want to unset almost > everything that begins with GIT_, other than those selected few that > are designed to be used to affect the tests" above the part you > touched? > > I am wondering if we should tweak the list there, instead of special > casing these two and these two only. There is a pattern that allows > anything that match "^GIT_(other|TRACE|things)", and I suspect that > the pattern is way too loose (i.e. it allows any garbage to follow, > and by allowing "TRACE", it also catches "TRACE2" because the former > is a prefix of the latter), which is a problem. Yes, due to the number of different TRACE2 modes, I figured it was cleaner to allow them by default and then explicitly unset the ones that cause trouble for trace parsing tests. But if you prefer to lock down the list, I can send an alternate fix. Thanks, Josh
On Thu, Jan 13, 2022 at 10:01:07PM -0800, Junio C Hamano wrote: > Josh Steadmon <steadmon@google.com> writes: > > > This behavior breaks certain tests that examine trace2 output when the > > tests run as a child of another git process, such as in `git rebase -x > > "make test"`. > > Well explained. The paragraph makes it clear how easy to trigger > and get bitten by this problem. > > > While we could fix this by unsetting the relevant variables in the > > affected tests (currently t0210, t0211, t0212, and t6421), this would > > leave other tests vulnerable to similar breakage if new test cases are > > added which inspect trace2 output. So fix this in general by unsetting > > GIT_TRACE2_PARENT_NAME and GIT_TRACE2_PARENT_SID in test-lib.sh. > > This probably makes sense, but I wonder how it interacts with a user > who runs "cd t && GIT_TRACE2=blah ./t0987-test-this.sh" to trace the > entire test script, though. > > > Reported-by: Emily Shaffer <emilyshaffer@google.com> > > Helped-by: Jonathan Tan <jonathantanmy@google.com> > > Signed-off-by: Josh Steadmon <steadmon@google.com> > > --- > > t/test-lib.sh | 2 ++ > > 1 file changed, 2 insertions(+) > > > > diff --git a/t/test-lib.sh b/t/test-lib.sh > > index 0f7a137c7d..e4716b0b86 100644 > > --- a/t/test-lib.sh > > +++ b/t/test-lib.sh > > @@ -449,6 +449,8 @@ unset VISUAL EMAIL LANGUAGE $("$PERL_PATH" -e ' > > unset XDG_CACHE_HOME > > unset XDG_CONFIG_HOME > > unset GITPERLLIB > > +unset GIT_TRACE2_PARENT_NAME > > +unset GIT_TRACE2_PARENT_SID > > Hmph. Have you noticed the more generic "We want to unset almost > everything that begins with GIT_, other than those selected few that > are designed to be used to affect the tests" above the part you > touched? > > I am wondering if we should tweak the list there, instead of special > casing these two and these two only. There is a pattern that allows > anything that match "^GIT_(other|TRACE|things)", and I suspect that > the pattern is way too loose (i.e. it allows any garbage to follow, > and by allowing "TRACE", it also catches "TRACE2" because the former > is a prefix of the latter), which is a problem. I was thinking the same thing, but I suspect that this may truly be different. That list says we should be able to keep anything that looks like GIT_TRACE in our environment. So the same should be true of TRACE2-related variables, I'd think. But the PARENT_NAME and PARENT_SID variables are (as far as I can tell from reading around) internal variables that help us piece together the names of the Git commands we ran. In other words, excluding all TRACE2 variables goes too far since it prevents us from being able to `GIT_TRACE2=1 make test`. But we would want to clear out any internal TRACE2 variables such as PARENT_NAME and PARENT_SID. Thanks, Taylor
Josh Steadmon <steadmon@google.com> writes: > Yes, due to the number of different TRACE2 modes, I figured it was > cleaner to allow them by default and then explicitly unset the ones that > cause trouble for trace parsing tests. I think I would agree that it is a better solution, and the design behind it (which makes me say it is better) should be recorded in the log message (and possibly in-code comment near the place we reset them) to help future developers who may add more TRACE2 variables. Thanks.
On 2022.01.18 13:50, Junio C Hamano wrote: > Josh Steadmon <steadmon@google.com> writes: > > > Yes, due to the number of different TRACE2 modes, I figured it was > > cleaner to allow them by default and then explicitly unset the ones that > > cause trouble for trace parsing tests. > > I think I would agree that it is a better solution, and the design > behind it (which makes me say it is better) should be recorded in > the log message (and possibly in-code comment near the place we > reset them) to help future developers who may add more TRACE2 > variables. > > Thanks. Fixed in V2. Thanks!
diff --git a/t/test-lib.sh b/t/test-lib.sh index 0f7a137c7d..e4716b0b86 100644 --- a/t/test-lib.sh +++ b/t/test-lib.sh @@ -449,6 +449,8 @@ unset VISUAL EMAIL LANGUAGE $("$PERL_PATH" -e ' unset XDG_CACHE_HOME unset XDG_CONFIG_HOME unset GITPERLLIB +unset GIT_TRACE2_PARENT_NAME +unset GIT_TRACE2_PARENT_SID TEST_AUTHOR_LOCALNAME=author TEST_AUTHOR_DOMAIN=example.com GIT_AUTHOR_EMAIL=${TEST_AUTHOR_LOCALNAME}@${TEST_AUTHOR_DOMAIN}
The trace2 subsystem can inherit certain information from parent processes via environment variables; e.g., the parent command name and session ID. This allows trace2 to note when a command is the child process of another Git process, and to adjust various pieces of output accordingly. This behavior breaks certain tests that examine trace2 output when the tests run as a child of another git process, such as in `git rebase -x "make test"`. While we could fix this by unsetting the relevant variables in the affected tests (currently t0210, t0211, t0212, and t6421), this would leave other tests vulnerable to similar breakage if new test cases are added which inspect trace2 output. So fix this in general by unsetting GIT_TRACE2_PARENT_NAME and GIT_TRACE2_PARENT_SID in test-lib.sh. Reported-by: Emily Shaffer <emilyshaffer@google.com> Helped-by: Jonathan Tan <jonathantanmy@google.com> Signed-off-by: Josh Steadmon <steadmon@google.com> --- t/test-lib.sh | 2 ++ 1 file changed, 2 insertions(+) base-commit: dcc0cd074f0c639a0df20461a301af6d45bd582e