std::chrono::locate_zone("Asia/Chungking") fails

[Matthias Klose]

[ Impact ]

forwarded from
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114770

```
#include <chrono>
int main()
{
  (void) std::chrono::locate_zone("Asia/Chungking");
}
```

With the latest tzdata (version 2024a-2) on Debian Sid this fails:

terminate called after throwing an instance of 'std::runtime_error'
  what(): tzdb: cannot locate zone: Asia/Chungking
Aborted (core dumped)

The problem is a Debian patch that enables link chaining, so that one link can have another link as its target:
https://sources.debian.org/patches/tzdata/2024a-2/ziguard.awk-Move-link-to-link-feature-from-vanguard-to-ma.patch/

This feature was added to tzdata in 2022, but isn't compatible with the expectations of the C++20 standard. When chrono::locate_zone finds a link, it expects its target to be a zone, not another link.

[ Test Plan ]

1. Install tzdata-legacy
2. Create `testcase.cpp`:

```
#include <chrono>
int main()
{
  (void) std::chrono::locate_zone("Asia/Chungking");
}
```

3. Compile: `g++ -std=c++20 -o testcase testcase.cpp`
4. Run: `./testcase`

The test case should not crash.

[Benjamin Drung (bdrung)]

This bug report is misleading, because Asia/Chungking is not a symlink to another symlink:

```
$ ls -l /usr/share/zoneinfo/Asia/Chungking /usr/share/zoneinfo/Asia/Shanghai
lrwxrwxrwx 1 root root 8 Apr 5 20:24 /usr/share/zoneinfo/Asia/Chungking -> Shanghai
-rw-r--r-- 1 root root 561 Apr 5 20:24 /usr/share/zoneinfo/Asia/Shanghai
```

Asia/Chungking is part of tzdata-legacy and this package is probably not installed.

Anyways, I'll replace the symlinks that point to symlinks.

[Steve Langasek (vorlon)]

Hello Matthias, or anyone else affected,

Accepted tzdata into noble-proposed. The package will build now and be available at https://launchpad.net/ubuntu/+source/tzdata/2024a-3ubuntu1 in a few hours, and then in the -proposed repository.

Please help us by testing this new package. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation on how to enable and use -proposed. Your feedback will aid us getting this update out to other Ubuntu users.

If this package fixes the bug for you, please add a comment to this bug, mentioning the version of the package you tested, what testing has been performed on the package and change the tag from verification-needed-noble to verification-done-noble. If it does not fix the bug for you, please add a comment stating that, and change the tag to verification-failed-noble. In either case, without details of your testing we will not be able to proceed.

Further information regarding the verification process can be found at https://wiki.ubuntu.com/QATeam/PerformingSRUVerification . Thank you in advance for helping!

N.B. The updated package will be released to -updates after the bug(s) fixed by this package have been verified and the package has been in -proposed for a minimum of 7 days.

[Benjamin Drung (bdrung)]

This is a follow-up fix for the fix in bug #2055718

[Benjamin Drung (bdrung)]

Verified that tzdata-legacy 2024a-2ubuntu1 crashes with the test case.

[Benjamin Drung (bdrung)]

Waiting for the package to hit the mirror...

[Ubuntu SRU Bot (ubuntu-sru-bot)]

All autopkgtests for the newly accepted tzdata (2024a-3ubuntu1) for noble have finished running.
The following regressions have been reported in tests triggered by the package:

chrony/unknown (ppc64el)
golang-github-lib-pq/1.10.9-2 (amd64, arm64)
pandas/2.1.4+dfsg-7 (arm64)
prometheus-alertmanager/0.26.0+ds-1 (armhf)
python-tempora/unknown (ppc64el)
reposurgeon/4.38-1 (ppc64el)
ruby-tzinfo/unknown (ppc64el)
tzdata/2024a-3ubuntu1 (armhf)
tzdata/unknown (ppc64el)
ubuntu-dev-tools/0.201ubuntu2 (amd64, arm64, armhf, i386, ppc64el, s390x)

Please visit the excuses page listed below and investigate the failures, proceeding afterwards as per the StableReleaseUpdates policy regarding autopkgtest regressions [1].

https://people.canonical.com/~ubuntu-archive/proposed-migration/noble/update_excuses.html#tzdata

[1] https://wiki.ubuntu.com/StableReleaseUpdates#Autopkgtest_Regressions

Thank you!

[Benjamin Drung (bdrung)]

Verification failed. The C++ code seems to read /usr/share/zoneinfo/tzdata.zi which still has the wrong link:

```
$ dpkg -s tzdata | grep ^Version
Version: 2024a-3ubuntu1
$ grep Asia/Chungking /usr/share/zoneinfo/tzdata.zi
L Asia/Chongqing Asia/Chungking
$ ls -l /usr/share/zoneinfo/Asia/Chungking
lrwxrwxrwx 1 root root 8 Apr 19 19:51 /usr/share/zoneinfo/Asia/Chungking -> Shanghai
```

[Benjamin Drung (bdrung)]

Uploaded tzdata 2024a-3ubuntu1.1 to apply the follow-up fix.

[Timo Aaltonen (tjaalton)]

Hello Matthias, or anyone else affected,

Accepted tzdata into noble-proposed. The package will build now and be available at https://launchpad.net/ubuntu/+source/tzdata/2024a-3ubuntu1.1 in a few hours, and then in the -proposed repository.

Please help us by testing this new package. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation on how to enable and use -proposed. Your feedback will aid us getting this update out to other Ubuntu users.

If this package fixes the bug for you, please add a comment to this bug, mentioning the version of the package you tested, what testing has been performed on the package and change the tag from verification-needed-noble to verification-done-noble. If it does not fix the bug for you, please add a comment stating that, and change the tag to verification-failed-noble. In either case, without details of your testing we will not be able to proceed.

Further information regarding the verification process can be found at https://wiki.ubuntu.com/QATeam/PerformingSRUVerification . Thank you in advance for helping!

N.B. The updated package will be released to -updates after the bug(s) fixed by this package have been verified and the package has been in -proposed for a minimum of 7 days.

[Benjamin Drung (bdrung)]

Verified that the testcase does not crash any more after updating tzdata:

```
$ ./testcase
$ dpkg -s tzdata | grep ^Version
Version: 2024a-3ubuntu1.1
```

[Ubuntu SRU Bot (ubuntu-sru-bot)]

All autopkgtests for the newly accepted tzdata (2024a-3ubuntu1.1) for noble have finished running.
The following regressions have been reported in tests triggered by the package:

astropy/unknown (armhf)
chrony/unknown (s390x)
dateparser/unknown (armhf)
golang-github-araddon-dateparse/unknown (armhf)
golang-github-rickb777-date/unknown (armhf)
golang-github-teambition-rrule-go/unknown (armhf)
libdatetime-timezone-perl/unknown (armhf)
orthanc/unknown (s390x)
pandas/unknown (armhf)
php8.3/unknown (s390x)
postgresql-16/unknown (armhf)
prometheus-alertmanager/unknown (armhf)
reposurgeon/unknown (armhf)

Please visit the excuses page listed below and investigate the failures, proceeding afterwards as per the StableReleaseUpdates policy regarding autopkgtest regressions [1].

https://people.canonical.com/~ubuntu-archive/proposed-migration/noble/update_excuses.html#tzdata

[1] https://wiki.ubuntu.com/StableReleaseUpdates#Autopkgtest_Regressions

Thank you!

[Benjamin Drung (bdrung)]

All autopkgtest runs succeeded except four autopkgtest fail on armhf with tmpfail:

* dateparser
* golang-github-rickb777-date
* prometheus-alertmanager
* reposurgeon

[Launchpad Janitor (janitor)]

This bug was fixed in the package tzdata - 2024a-4ubuntu1

---------------
tzdata (2024a-4ubuntu1) oracular; urgency=medium

  * Merge with Debian unstable. Remaining changes:
    - Ship 2024a ICU timezone data which are utilized by PHP in tzdata-icu
    - Add autopkgtest test case for ICU timezone data
    - Do not rename NEWS into changelog.gz, this fixes a build failure on
      moment-timezone.js
    - Point Vcs-Browser/Git to Launchpad
    - generate_debconf_templates: Work around AttributeError on icu import

tzdata (2024a-4) unstable; urgency=medium

  * d/rules: Support creating symlinks pointing to symlinks
  * Fixup for avoid timezones being symlinks to symlinks (LP: #2062522)

tzdata (2024a-3) unstable; urgency=medium

  * Avoid timezones being symlinks to symlinks to avoid breaking C++20 standard
    expectation (LP: #2062522)

 -- Benjamin Drung <email address hidden> Thu, 02 May 2024 18:34:12 +0200

[Simon Chopin (schopin)]

It seems this doesn't have anything to do with glibc? Marking as Invalid there.

[Launchpad Janitor (janitor)]

This bug was fixed in the package tzdata - 2024a-3ubuntu1.1

---------------
tzdata (2024a-3ubuntu1.1) noble; urgency=medium

  * d/rules: Support creating symlinks pointing to symlinks
  * Fixup for avoid timezones being symlinks to symlinks (LP: #2062522)

tzdata (2024a-3ubuntu1) noble; urgency=medium

  * Merge with Debian unstable. Remaining changes:
    - Ship 2024a ICU timezone data which are utilized by PHP in tzdata-icu
    - Add autopkgtest test case for ICU timezone data
    - Do not rename NEWS into changelog.gz, this fixes a build failure on
      moment-timezone.js
    - Point Vcs-Browser/Git to Launchpad
    - generate_debconf_templates: Work around AttributeError on icu import

tzdata (2024a-3) unstable; urgency=medium

  * Avoid timezones being symlinks to symlinks to avoid breaking C++20 standard
    expectation (LP: #2062522)

 -- Benjamin Drung <email address hidden> Fri, 03 May 2024 13:27:11 +0200

[Brian Murray (brian-murray)]

The verification of the Stable Release Update for tzdata has completed successfully and the package is now being released to -updates. Subsequently, the Ubuntu Stable Release Updates Team is being unsubscribed and will not receive messages about this bug report. In the event that you encounter a regression using the package from -updates please report a new bug using ubuntu-bug and tag the bug report regression-update so we can easily find any regressions.