This may occur when stderr is a tty but stdin is empty.
E.g.
$ nix build </dev/null
error: unexpected EOF reading a line
These stdio handles are how some non-interactive sandboxes behave,
including the Nix build sandbox and Hercules CI Effects.
tests/functional/help.sh calls nix-* commands with option --help
if nix is built without documentation the option --help throws an error
because the man page it wants to display is missing
This overall seems like insecure tmp file handling to me. Because other
users could replace files in /tmp with a symlink and make the nix-shell
override other files.
fixes https://github.com/NixOS/nix/issues/11470
A test added recently checks that when trying to deserialize a NAR with
two files that Unicode-normalize to the same result either succeeds on
Linux, or fails with an "already exists" error on Darwin. However,
failing with an "already exists" error can in fact also happen on Linux,
when using ZFS with the proper utf8 and Unicode normalization options
set.
This commit fixes the issue by not assuming the behavior from the
current system, but just by blindly checking that either one of the two
aforementioned possibilities happen, whether on Darwin or on Linux.
Additionally, we check that the Unicode normalization behaviour of
nix-store is the same as the host file system.
This leads to confusion about what the command does.
E.g. https://github.com/NixOS/nix/issues/9359
- Move the description up
- Remove details about the individual formatters
As a prelude to making "or" work like a normal variable, emit a warning
any time the "fn or" production is used in a context that will change
how it is parsed when that production is refactored.
In detail: in the future, OR_KW will be moved to expr_simple, and the
cursed ExprCall production that is currently part of the expr_select
nonterminal will be generated "normally" in expr_app instead. Any
productions that accept an expr_select will be affected, except for the
expr_app nonterminal itself (because, while expr_app has a production
accepting a bare expr_select, its other production will continue to
accept "fn or" expressions). So all we need to do is emit an appropriate
warning when an expr_simple representing a cursed ExprCall is accepted
in one of those productions without first going through expr_app.
As the warning message describes, users can suppress the warning by
wrapping their problematic "fn or" expressions in parentheses. For
example, "f g or" can be made future-proof by rewriting it as
"f (g or)"; similarly "[ x y or ]" can be rewritten as "[ x (y or) ]",
etc. The parentheses preserve the current grouping behavior, as in the
future "f g or" will be parsed as "(f g) or", just like
"f g anything-else" is grouped. (Mechanically, this suppresses the
warning because the problem ExprCalls go through the
"expr_app : expr_select" production, which resets the cursed status on
the ExprCall.)
Because of an objc quirk[1], calling curl_global_init for the first time
after fork() will always result in a crash.
Up until now the solution has been to set
OBJC_DISABLE_INITIALIZE_FORK_SAFETY for every nix process to ignore
that error.
This is less than ideal because we were setting it in package.nix,
which meant that running nix tests locally would fail because
that variable was not set.
Instead of working around that error we address it at the core -
by calling curl_global_init inside initLibStore, which should mean
curl will already have been initialized by the time we try to do so in
a forked process.
[1] 01edf1705f/runtime/objc-initialize.mm (L614-L636)
(cherry-picked and adapted from c7d97802e4)
Note: in general, we rely on the OS to tell us if a name is invalid or
if two names normalize in the same way. But for security, we do want
to make sure that we catch '.', '..', slashes and NUL characters. (NUL
characters aren't really a security issue, but since they would be
truncated when we pass them to the OS, it would be canonicity problem.)
