lix-project/lix
22
79
Fork 54
Code Issues 518 Code Review (Gerrit) Projects 8 Releases Packages Wiki Activity

Crash running nix flake update #759

New issue
Closed
opened 2025-03-24 18:10:26 +00:00 by 9p4 · 4 comments
9p4 commented 2025-03-24 18:10:26 +00:00
Copy link

Describe the bug

When running nix flake update, Lix crashes occasionally.

Steps To Reproduce

  1. Run nix flake update in my Nix configs at commit 8c4a394 with the same version of Lix

Expected behavior

I expected nix flake update to not crash.

nix --version output

nix (Lix, like Nix) 2.93.0-dev-pre20250319-2491b7c
System type: x86_64-linux
Additional system types: aarch64-linux, i686-linux
Features: gc, signed-caches
System configuration file: /etc/nix/nix.conf
User configuration files: /home/ersei/.config/nix/nix.conf:/etc/xdg/nix/nix.conf:/home/ersei/.local/state/nix/profile/etc/xdg/nix/nix.conf:/etc/profiles/per-user/ersei/etc/xdg/nix/nix.conf:/home/ersei/.nix-profile/etc/xdg/nix/nix.conf:/nix/profile/etc/xdg/nix/nix.conf:/home/ersei/.local/state/nix/profile/etc/xdg/nix/nix.conf:/etc/profiles/per-user/ersei/etc/xdg/nix/nix.conf:/nix/var/nix/profiles/default/etc/xdg/nix/nix.conf:/run/current-system/sw/etc/xdg/nix/nix.conf
Store directory: /nix/store
State directory: /nix/var/nix
Data directory: /nix/store/0z44c1bg3s7f2rw7z8b2ryvzncz3bqv3-lix-2.93.0-dev-pre20250319-2491b7c/share

Additional context

warning: error: unable to download 'https://api.github.com/repos/nix-community/home-manager/commits/master': Resolving timed out after 5000 milliseconds (curl error code=28); retrying in 314 ms (attempt 1/5)
downloading 'https://api.github.com/repos/nix-community/home-manager/commits/master'Lix crashed. This is a bug. We would appreciate if you report it along with what caused it at https://git.lix.systems/lix-project/lix/issues with the following information included:

Exception: nlohmann::json_abi_v3_11_3::detail::parse_error: [json.exception.parse_error.101] parse error at line 1, column 1: syntax error while parsing value - invalid literal; last read: '<U+001F>'
Stack trace:
 0# nix::getStackTrace[abi:cxx11]() in /nix/store/0z44c1bg3s7f2rw7z8b2ryvzncz3bqv3-lix-2.93.0-dev-pre20250319-2491b7c/lib/liblixutil.so
 1# 0x00007F4E759FE853 in /nix/store/0z44c1bg3s7f2rw7z8b2ryvzncz3bqv3-lix-2.93.0-dev-pre20250319-2491b7c/lib/liblixmain.so
 2# 0x00007F4E748BF20A in /nix/store/6kbrc4ca98srlfpgyaayl2q9zpg1gys6-gcc-14-20241116-lib/lib/libstdc++.so.6
 3# std::unexpected() in /nix/store/6kbrc4ca98srlfpgyaayl2q9zpg1gys6-gcc-14-20241116-lib/lib/libstdc++.so.6
 4# 0x00007F4E748BF1FE in /nix/store/6kbrc4ca98srlfpgyaayl2q9zpg1gys6-gcc-14-20241116-lib/lib/libstdc++.so.6
 5# void boost::outcome_v2::policy::exception_ptr_rethrow<std::tuple<nix::fetchers::Tree, nix::FlakeRef, nix::FlakeRef>, std::__exception_ptr::exception_ptr, void>::wide_value_check<boost::outcome_v2::detail::basic_result_value_observers<boost::outcome_v2::detail::basic_result_storage<std::tuple<nix::fetchers::Tree, nix::FlakeRef, nix::FlakeRef>, std::__exception_ptr::exception_ptr, boost::outcome_v2::policy::exception_ptr_rethrow<std::tuple<nix::fetchers::Tree, nix::FlakeRef, nix::FlakeRef>, std::__exception_ptr::exception_ptr, void> >, std::tuple<nix::fetchers::Tree, nix::FlakeRef, nix::FlakeRef>, boost::outcome_v2::policy::exception_ptr_rethrow<std::tuple<nix::fetchers::Tree, nix::FlakeRef, nix::FlakeRef>, std::__exception_ptr::exception_ptr, void> > >(boost::outcome_v2::detail::basic_result_value_observers<boost::outcome_v2::detail::basic_result_storage<std::tuple<nix::fetchers::Tree, nix::FlakeRef, nix::FlakeRef>, std::__exception_ptr::exception_ptr, boost::outcome_v2::policy::exception_ptr_rethrow<std::tuple<nix::fetchers::Tree, nix::FlakeRef, nix::FlakeRef>, std::__exception_ptr::exception_ptr, void> >, std::tuple<nix::fetchers::Tree, nix::FlakeRef, nix::FlakeRef>, boost::outcome_v2::policy::exception_ptr_rethrow<std::tuple<nix::fetchers::Tree, nix::FlakeRef, nix::FlakeRef>, std::__exception_ptr::exception_ptr, void> >&&) in /nix/store/0z44c1bg3s7f2rw7z8b2ryvzncz3bqv3-lix-2.93.0-dev-pre20250319-2491b7c/lib/liblixexpr.so
 6# std::tuple<nix::fetchers::Tree, nix::FlakeRef, nix::FlakeRef> nix::detail::runAsyncUnwrap<std::tuple<nix::fetchers::Tree, nix::FlakeRef, nix::FlakeRef> >(boost::outcome_v2::basic_result<std::tuple<nix::fetchers::Tree, nix::FlakeRef, nix::FlakeRef>, std::__exception_ptr::exception_ptr, std::conditional<false, boost::outcome_v2::policy::terminate, std::conditional<false, boost::outcome_v2::policy::error_code_throw_as_system_error<std::tuple<nix::fetchers::Tree, nix::FlakeRef, nix::FlakeRef>, std::__exception_ptr::exception_ptr, void>, std::conditional<true, boost::outcome_v2::policy::exception_ptr_rethrow<std::tuple<nix::fetchers::Tree, nix::FlakeRef, nix::FlakeRef>, std::__exception_ptr::exception_ptr, void>, boost::outcome_v2::policy::fail_to_compile_observers>::type>::type>::type>) in /nix/store/0z44c1bg3s7f2rw7z8b2ryvzncz3bqv3-lix-2.93.0-dev-pre20250319-2491b7c/lib/liblixexpr.so
 7# 0x00007F4E7502F8E9 in /nix/store/0z44c1bg3s7f2rw7z8b2ryvzncz3bqv3-lix-2.93.0-dev-pre20250319-2491b7c/lib/liblixexpr.so
 8# 0x00007F4E7503E2F5 in /nix/store/0z44c1bg3s7f2rw7z8b2ryvzncz3bqv3-lix-2.93.0-dev-pre20250319-2491b7c/lib/liblixexpr.so
 9# 0x00007F4E7503B9FF in /nix/store/0z44c1bg3s7f2rw7z8b2ryvzncz3bqv3-lix-2.93.0-dev-pre20250319-2491b7c/lib/liblixexpr.so
10# nix::flake::lockFlake(nix::EvalState&, nix::FlakeRef const&, nix::flake::LockFlags const&) in /nix/store/0z44c1bg3s7f2rw7z8b2ryvzncz3bqv3-lix-2.93.0-dev-pre20250319-2491b7c/lib/liblixexpr.so
11# 0x000055C2C0E2E581 in nix
12# nix::StoreCommand::run() in /nix/store/0z44c1bg3s7f2rw7z8b2ryvzncz3bqv3-lix-2.93.0-dev-pre20250319-2491b7c/lib/liblixcmd.so
13# 0x000055C2C0E2CF0A in nix
14# 0x000055C2C0E6AB50 in nix
15# 0x000055C2C0E6D4DD in nix
16# nix::handleExceptions(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, std::function<void ()>) in /nix/store/0z44c1bg3s7f2rw7z8b2ryvzncz3bqv3-lix-2.93.0-dev-pre20250319-2491b7c/lib/liblixmain.so
17# 0x000055C2C0E6CF9B in nix
18# 0x00007F4E7442A1FE in /nix/store/cmpyglinc9xl9pr4ymx8akl286ygl64x-glibc-2.40-66/lib/libc.so.6
19# __libc_start_main in /nix/store/cmpyglinc9xl9pr4ymx8akl286ygl64x-glibc-2.40-66/lib/libc.so.6
20# 0x000055C2C0D986A5 in nix

fish: Job 1, '/nix/store/vgn2m44a8jx891zblms5…' terminated by signal SIGABRT (Abort)
## Describe the bug When running `nix flake update`, Lix crashes occasionally. ## Steps To Reproduce 1. Run `nix flake update` in my Nix configs at commit [8c4a394](https://git.ersei.net/nix-configs.git/commit/?id=8c4a39432ae3856b3d129a05b91c444b08eb7f75) with the same version of Lix ## Expected behavior I expected `nix flake update` to not crash. ## `nix --version` output ``` nix (Lix, like Nix) 2.93.0-dev-pre20250319-2491b7c System type: x86_64-linux Additional system types: aarch64-linux, i686-linux Features: gc, signed-caches System configuration file: /etc/nix/nix.conf User configuration files: /home/ersei/.config/nix/nix.conf:/etc/xdg/nix/nix.conf:/home/ersei/.local/state/nix/profile/etc/xdg/nix/nix.conf:/etc/profiles/per-user/ersei/etc/xdg/nix/nix.conf:/home/ersei/.nix-profile/etc/xdg/nix/nix.conf:/nix/profile/etc/xdg/nix/nix.conf:/home/ersei/.local/state/nix/profile/etc/xdg/nix/nix.conf:/etc/profiles/per-user/ersei/etc/xdg/nix/nix.conf:/nix/var/nix/profiles/default/etc/xdg/nix/nix.conf:/run/current-system/sw/etc/xdg/nix/nix.conf Store directory: /nix/store State directory: /nix/var/nix Data directory: /nix/store/0z44c1bg3s7f2rw7z8b2ryvzncz3bqv3-lix-2.93.0-dev-pre20250319-2491b7c/share ``` ## Additional context ``` warning: error: unable to download 'https://api.github.com/repos/nix-community/home-manager/commits/master': Resolving timed out after 5000 milliseconds (curl error code=28); retrying in 314 ms (attempt 1/5) downloading 'https://api.github.com/repos/nix-community/home-manager/commits/master'Lix crashed. This is a bug. We would appreciate if you report it along with what caused it at https://git.lix.systems/lix-project/lix/issues with the following information included: Exception: nlohmann::json_abi_v3_11_3::detail::parse_error: [json.exception.parse_error.101] parse error at line 1, column 1: syntax error while parsing value - invalid literal; last read: '<U+001F>' Stack trace: 0# nix::getStackTrace[abi:cxx11]() in /nix/store/0z44c1bg3s7f2rw7z8b2ryvzncz3bqv3-lix-2.93.0-dev-pre20250319-2491b7c/lib/liblixutil.so 1# 0x00007F4E759FE853 in /nix/store/0z44c1bg3s7f2rw7z8b2ryvzncz3bqv3-lix-2.93.0-dev-pre20250319-2491b7c/lib/liblixmain.so 2# 0x00007F4E748BF20A in /nix/store/6kbrc4ca98srlfpgyaayl2q9zpg1gys6-gcc-14-20241116-lib/lib/libstdc++.so.6 3# std::unexpected() in /nix/store/6kbrc4ca98srlfpgyaayl2q9zpg1gys6-gcc-14-20241116-lib/lib/libstdc++.so.6 4# 0x00007F4E748BF1FE in /nix/store/6kbrc4ca98srlfpgyaayl2q9zpg1gys6-gcc-14-20241116-lib/lib/libstdc++.so.6 5# void boost::outcome_v2::policy::exception_ptr_rethrow<std::tuple<nix::fetchers::Tree, nix::FlakeRef, nix::FlakeRef>, std::__exception_ptr::exception_ptr, void>::wide_value_check<boost::outcome_v2::detail::basic_result_value_observers<boost::outcome_v2::detail::basic_result_storage<std::tuple<nix::fetchers::Tree, nix::FlakeRef, nix::FlakeRef>, std::__exception_ptr::exception_ptr, boost::outcome_v2::policy::exception_ptr_rethrow<std::tuple<nix::fetchers::Tree, nix::FlakeRef, nix::FlakeRef>, std::__exception_ptr::exception_ptr, void> >, std::tuple<nix::fetchers::Tree, nix::FlakeRef, nix::FlakeRef>, boost::outcome_v2::policy::exception_ptr_rethrow<std::tuple<nix::fetchers::Tree, nix::FlakeRef, nix::FlakeRef>, std::__exception_ptr::exception_ptr, void> > >(boost::outcome_v2::detail::basic_result_value_observers<boost::outcome_v2::detail::basic_result_storage<std::tuple<nix::fetchers::Tree, nix::FlakeRef, nix::FlakeRef>, std::__exception_ptr::exception_ptr, boost::outcome_v2::policy::exception_ptr_rethrow<std::tuple<nix::fetchers::Tree, nix::FlakeRef, nix::FlakeRef>, std::__exception_ptr::exception_ptr, void> >, std::tuple<nix::fetchers::Tree, nix::FlakeRef, nix::FlakeRef>, boost::outcome_v2::policy::exception_ptr_rethrow<std::tuple<nix::fetchers::Tree, nix::FlakeRef, nix::FlakeRef>, std::__exception_ptr::exception_ptr, void> >&&) in /nix/store/0z44c1bg3s7f2rw7z8b2ryvzncz3bqv3-lix-2.93.0-dev-pre20250319-2491b7c/lib/liblixexpr.so 6# std::tuple<nix::fetchers::Tree, nix::FlakeRef, nix::FlakeRef> nix::detail::runAsyncUnwrap<std::tuple<nix::fetchers::Tree, nix::FlakeRef, nix::FlakeRef> >(boost::outcome_v2::basic_result<std::tuple<nix::fetchers::Tree, nix::FlakeRef, nix::FlakeRef>, std::__exception_ptr::exception_ptr, std::conditional<false, boost::outcome_v2::policy::terminate, std::conditional<false, boost::outcome_v2::policy::error_code_throw_as_system_error<std::tuple<nix::fetchers::Tree, nix::FlakeRef, nix::FlakeRef>, std::__exception_ptr::exception_ptr, void>, std::conditional<true, boost::outcome_v2::policy::exception_ptr_rethrow<std::tuple<nix::fetchers::Tree, nix::FlakeRef, nix::FlakeRef>, std::__exception_ptr::exception_ptr, void>, boost::outcome_v2::policy::fail_to_compile_observers>::type>::type>::type>) in /nix/store/0z44c1bg3s7f2rw7z8b2ryvzncz3bqv3-lix-2.93.0-dev-pre20250319-2491b7c/lib/liblixexpr.so 7# 0x00007F4E7502F8E9 in /nix/store/0z44c1bg3s7f2rw7z8b2ryvzncz3bqv3-lix-2.93.0-dev-pre20250319-2491b7c/lib/liblixexpr.so 8# 0x00007F4E7503E2F5 in /nix/store/0z44c1bg3s7f2rw7z8b2ryvzncz3bqv3-lix-2.93.0-dev-pre20250319-2491b7c/lib/liblixexpr.so 9# 0x00007F4E7503B9FF in /nix/store/0z44c1bg3s7f2rw7z8b2ryvzncz3bqv3-lix-2.93.0-dev-pre20250319-2491b7c/lib/liblixexpr.so 10# nix::flake::lockFlake(nix::EvalState&, nix::FlakeRef const&, nix::flake::LockFlags const&) in /nix/store/0z44c1bg3s7f2rw7z8b2ryvzncz3bqv3-lix-2.93.0-dev-pre20250319-2491b7c/lib/liblixexpr.so 11# 0x000055C2C0E2E581 in nix 12# nix::StoreCommand::run() in /nix/store/0z44c1bg3s7f2rw7z8b2ryvzncz3bqv3-lix-2.93.0-dev-pre20250319-2491b7c/lib/liblixcmd.so 13# 0x000055C2C0E2CF0A in nix 14# 0x000055C2C0E6AB50 in nix 15# 0x000055C2C0E6D4DD in nix 16# nix::handleExceptions(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, std::function<void ()>) in /nix/store/0z44c1bg3s7f2rw7z8b2ryvzncz3bqv3-lix-2.93.0-dev-pre20250319-2491b7c/lib/liblixmain.so 17# 0x000055C2C0E6CF9B in nix 18# 0x00007F4E7442A1FE in /nix/store/cmpyglinc9xl9pr4ymx8akl286ygl64x-glibc-2.40-66/lib/libc.so.6 19# __libc_start_main in /nix/store/cmpyglinc9xl9pr4ymx8akl286ygl64x-glibc-2.40-66/lib/libc.so.6 20# 0x000055C2C0D986A5 in nix fish: Job 1, '/nix/store/vgn2m44a8jx891zblms5…' terminated by signal SIGABRT (Abort) ```
lix-coredump.gz
1.8 MiB
just1602 commented 2025-03-24 18:15:20 +00:00
Member
Copy link

It seems to be a duplicate of #753 I opened I couple of days ago. For me it want away when I reran nix flake update and never came back, is it always crashing on your side?

It seems to be a duplicate of #753 I opened I couple of days ago. For me it want away when I reran `nix flake update` and never came back, is it always crashing on your side?
9p4 commented 2025-03-24 18:17:52 +00:00
Author
Copy link

It has only crashed once so far, but that "once" was when DNS was timing out on the first attempt. I'll see if that is part of the issue.

It has only crashed once so far, but that "once" was when DNS was timing out on the first attempt. I'll see if that is part of the issue.
👍 1
9p4 commented 2025-03-25 02:49:28 +00:00
Author
Copy link

I forced a DNS timeout and the crash did not happen, so it might be something else instead. I'll poke around the coredump.

I forced a DNS timeout and the crash did not happen, so it might be something else instead. I'll poke around the coredump.
lix-bot commented 2025-03-26 18:35:53 +00:00
Member
Copy link

This issue was mentioned on Gerrit on the following CLs:

  • commit message in cl/2907 ("treewide: handle JSON parse errors")
<!-- GERRIT_LINKBOT: {"cls": [{"backlink": "https://gerrit.lix.systems/c/lix/+/2907", "number": 2907, "kind": "commit message"}], "cl_meta": {"2907": {"change_title": "treewide: handle JSON parse errors"}}} --> This issue was mentioned on Gerrit on the following CLs: * commit message in [cl/2907](https://gerrit.lix.systems/c/lix/+/2907) ("treewide: handle JSON parse errors")
Sign in to join this conversation.
No Branch/Tag specified
Branches Tags
main
ci-config
release-2.91
release-2.92
release-2.93
sb/raito/darwin-kqueue-disablement
sb/raito/hydra-merge
sb/pennae/ci-config
sb/raito/phantom-referrers-gc
repl-overlay-example
reuse-compliance
release-2.90
sb/pennae/io-rewrite
git-series/activity-cleanup
sb/tom-hubrecht/primops.cc-v2
sb/bacchanalia/cache-strlen%topic=substr-perf
sb/qyriad/beta-1
sb/qyriad/2.90-beta.0
sb/rbt/test-branch
sb/rbt/justfile
sb/rbt/repl-overlays
sb/qyriad/maint-meson
sb/qyriad/maint/meson
sb/puck/meson-c-api
sb/jade/burn-it-all
dependabot/github_actions/zeebe-io/backport-action-2.4.1
dependabot/github_actions/cachix/install-nix-action-25
dependabot/github_actions/actions/labeler-5
dependabot/github_actions/cachix/cachix-action-14
2.93.3
2.92.3
2.93.2
2.91.3
2.92.2
2.91.2
2.93.1
2.93.0
2.92.0
2.91.1
2.91.0
2.90.0
2.90.0-rc1
2.90-beta.1
2.90-beta.0
Labels
Clear labels   
Affects/CppNix

Probably affects CppNix. This is a best-effort tag for troubles in old code; it exists to inform the CppNix team about problems they might care about also.

  
Affects/Nightly

Found in Lix nightly.

  
Affects/Only nightly

Tag for regressions in Lix nightly. We intend to fix all of these prior to releases.

  
Affects/Stable

Affects the stable release of Lix. Usually such issues affect nightly too but there is no guarantee.

  
Area/build-packaging

regarding the building or packaging of Lix itself

  
Area/cli

The command line interface of Lix

  
Area/evaluator

libexpr and anything else related to the evaluation of Nix expressions

  
Area/fetching

Fetching sources or other materials from the World Wide Web in Lix

  
Area/flakes

   
Area/language

language design, features, extensions, etc

  
Area/lix ci

Lix's own CI and deployment pipeline

  
Area/nix-eval-jobs

nix-eval-jobs for Lix

  
Area/profiles

profiles: nix-env, nix profile, and installer flavors all alike

  
Area/protocol

The protocol, used for communicating between the client and the daemon

  
Area/releng

Release engineering

  
Area/remote-builds

remote builds

  
Area/repl

nix repl

  
Area/repl/debugger

The --debugger that brings up a Lix repl

  
Area/store

libstore and anything else relating to the Nix store

  
bug

it's a bug

  
Context
contributors
This issue might require some context that isn't written down. It might be possible to handle as a person who already worked on this area.

  
Context
drive-by
This issue contains all the necessary information to do a drive-by contribution: that is, you don't have to talk with anyone at all to successfully solve it!

  
Context
maintainers
This issue requires a lot of know-how. Attention from maintainers is needed to proceed.

  
Context
RFD
This issue needs discussion from multiple maintainers and interested parties: it's a Request For Discussion.

  
crash 💥

Lix crashes (possibly bad error handling)

  
Cross Compilation

   
devx

development experience issues

  
docs

requires or is about documentation changes

  
Downstream Dependents

regarding an external tool's usage with Lix (e.g. nix-eval-jobs)

  
E/easy

bug is relatively simple and could simply be fixed with some minor effort

  
E/hard

this issue should probably be solved with close involvement of an expert

  
E/help wanted

maintainers may not get to this soon, but we want it fixed

  
E/reproducible

This bug is reproducible and obvious.

  
E/requires rearchitecture

this bug cannot be fixed properly without fixing a known architectural flaw

  
imported

Issue imported from upstream nix (please do not remove this label, it will cause dupes if import is rerun)

  
Language/Bash

   
Language/C++

   
Language/NixLang

   
Language/Python

   
Language/Rust

   
Needs Langver

We can't get to this until we implement language versioning

  
OS/Linux

Affects specifically Lix on Linux

  
OS/macOS

Affects specifically Lix on macOS

  
performance

make lix go faster

  
regression

This is a regression since some previous version of Lix

  
release-blocker

Blocks public release

  
stability

Fixing this makes the software more stable

  
Status
blocked
Blocked on something

  
Status
invalid
not our bug, duplicate, similar

  
Status
postponed
closed but should maybe look at later (generally with S-wontfix)

  
Status
wontfix
We chose not to change this (see issue comments for more detail).

  
testing

Tests that should be added

  
testing/flakey

Tests that are unreliable/flakey (not to be confused with flakes that test)

  
Topic/Large Scale Installations

Large scale installations of Lix, e.g. NixOS Hydra, Lix CI, big corporate installations etc.

  
ux

makes the user experience better :)

No labels
Affects/CppNix
Affects/Nightly
Affects/Only nightly
Affects/Stable
Area/build-packaging
Area/cli
Area/evaluator
Area/fetching
Area/flakes
Area/language
Area/lix ci
Area/nix-eval-jobs
Area/profiles
Area/protocol
Area/releng
Area/remote-builds
Area/repl
Area/repl/debugger
Area/store
bug
Context
contributors
Context
drive-by
Context
maintainers
Context
RFD
crash 💥
Cross Compilation
devx
docs
Downstream Dependents
E/easy
E/hard
E/help wanted
E/reproducible
E/requires rearchitecture
imported
Language/Bash
Language/C++
Language/NixLang
Language/Python
Language/Rust
Needs Langver
OS/Linux
OS/macOS
performance
regression
release-blocker
stability
Status
blocked
Status
invalid
Status
postponed
Status
wontfix
testing
testing/flakey
Topic/Large Scale Installations
ux
Milestone
Clear milestone
No items
No milestone
Projects
Clear projects
No items
No project
Assignees
Clear assignees
No assignees
3 participants
Notifications
Due date
The due date is invalid or out of range. Please use the format "yyyy-mm-dd".

No due date set.

Dependencies

No dependencies set.

Reference: lix-project/lix#759
No description provided.
Delete branch "%!s()"

Deleting a branch is permanent. Although the deleted branch may continue to exist for a short time before it actually gets removed, it CANNOT be undone in most cases. Continue?