* lib: introduce imap0, imap1
For historical reasons, imap starts counting at 1 and it's not
consistent with the rest of the lib.
So for now we split imap into imap0 that starts counting at zero and
imap1 that starts counting at 1. And imap is marked as deprecated.
See c71e2d4235 (commitcomment-21873221)
* replace uses of lib.imap
* lib: move imap to deprecated.nix
Quoting various characters that the shell *may* interpret specially is a
very fragile thing to do.
I've used something more robust all over the place in various Nix
expression I've written just because I didn't trust escapeShellArg.
Here is a proof of concept showing that I was indeed right in
distrusting escapeShellArg:
with import <nixpkgs> {};
let
payload = runCommand "payload" {} ''
# \x00 is not allowed for Nix strings, so let's begin at 1
for i in $(seq 1 255); do
echo -en "\\x$(printf %02x $i)"
done > "$out"
'';
escapers = with lib; {
current = escapeShellArg;
better = arg: let
backslashEscapes = stringToCharacters "\"\\ ';$`()|<>\r\t*[]&!~#";
search = backslashEscapes ++ [ "\n" ];
replace = map (c: "\\${c}") backslashEscapes ++ [ "'\n'" ];
in replaceStrings search replace (toString arg);
best = arg: "'${replaceStrings ["'"] ["'\\''"] (toString arg)}'";
};
testWith = escaper: let
escaped = escaper (builtins.readFile payload);
in runCommand "test" {} ''
if ! r="$(bash -c ${escapers.best "echo -nE ${escaped}"} 2> /dev/null)"
then
echo bash eval error > "$out"
exit 0
fi
if echo -n "$r" | cmp -s "${payload}"; then
echo success > "$out"
else
echo failed > "$out"
fi
'';
in runCommand "results" {} ''
echo "Test results:"
${lib.concatStrings (lib.mapAttrsToList (name: impl: ''
echo " ${name}: $(< "${testWith impl}")"
'') escapers)}
exit 1
''
The resulting output is the following:
Test results:
best: success
better: success
current: bash eval error
I did the "better" implementation just to illustrate that the method of
quoting only "harmful" characters results in madness in terms of
implementation and performance.
Signed-off-by: aszlig <aszlig@redmoonstudios.org>
Cc: @edolstra, @zimbatm
For example, this allows writing
nix.package = /nix/store/786mlvhd17xvcp2r4jmmay6jj4wj6b7f-nix-1.10pre4206_896428c;
Also, document types.package in the manual.
