lib.strings.escapeC produces single‐digit hexadecimal strings for
character values ≤ 15, which results in an ambiguity. If the following
character is a hex digit, it will be interpreted as being part of the
escape sequence.
systemd, which also relies on C‐style escape sequences, does not
decode single‐digit sequences at all, even if unambiguous.
Padding the hexadecimal string with "0" avoids this problem.
Format all Nix files using the officially approved formatter,
making the CI check introduced in the previous commit succeed:
nix-build ci -A fmt.check
This is the next step of the of the [implementation](https://github.com/NixOS/nixfmt/issues/153)
of the accepted [RFC 166](https://github.com/NixOS/rfcs/pull/166).
This commit will lead to merge conflicts for a number of PRs,
up to an estimated ~1100 (~33%) among the PRs with activity in the past 2
months, but that should be lower than what it would be without the previous
[partial treewide format](https://github.com/NixOS/nixpkgs/pull/322537).
Merge conflicts caused by this commit can now automatically be resolved while rebasing using the
[auto-rebase script](8616af08d9/maintainers/scripts/auto-rebase).
If you run into any problems regarding any of this, please reach out to the
[formatting team](https://nixos.org/community/teams/formatting/) by
pinging @NixOS/nix-formatting.
These utilities will now leave the string undisturbed if it doesn't need to be quoted (because it doesn't have any special characters). This can help generate nicer-looking command lines.
This also transitively improves the output of `lib.toGNUCommandLine` which uses `escapeShellArg` internally
`strings.trim` returns a copy of the string with all leading and trailing
whitespace removed.
`strings.trimWith` does the same thing, but calling code can decide
whether to trim the start and/or end of the string.
The deprecation warnings in lib were wildly inconsistent. Different
formulations were used in different places for the same meaning. Some warnings
used builtins.trace instead of lib.warn, which prevents silencing; one even
only had a comment instead. Make everything more uniform.
lib.{hasPrefix,hasInfix,hasSuffix} would otherwise return an
always-false result, which can be very unexpected:
nix-repl> lib.strings.hasPrefix ./lib ./lib/meta.nix
false
In the current implementation of Nix, this list would be allocated
over and over. Iirc pennae tried to optimize static list allocation,
but gained no significant performance improvement.
Yes, this function name is inconveniently long, but it is important
for the name to explicitly reference the function and not be mistaken
for the implicit string conversions, which only happen for a smaller
set of values.
