common-eval-args: raise warning if --arg isn't a valid Nix identifier

See lix-project/lix#496.

The core idea is to be able to do e.g.

    nix-instantiate -A some-nonfree-thing --arg config.allowUnfree true

which is currently not possible since `config.allowUnfree` is
interpreted as attribute name with a dot in it.

In order to change that (probably), Jade suggested to find out if there
are any folks out there relying on this behavior.

For such a use-case, it may still be possible to accept strings, i.e.
`--arg '"config.allowUnfree"'.

Change-Id: I986c73619fbd87a95b55e2f0ac03feaed3de2d2d
This commit is contained in:
Maximilian Bosch 2024-09-15 16:13:22 +02:00
parent 727258241f
commit 80202e3ca3
Signed by: ma27
SSH key fingerprint: SHA256:d7dmwHmpai66L6KIXA+wxzVbkPq0nGLrcHK3ZNroqZY

View file

@ -9,8 +9,24 @@
#include "store-api.hh"
#include "command.hh"
#include <regex>
namespace nix {
static std::regex const identifierRegex("^[A-Za-z_][A-Za-z0-9_'-]*$");
static void warnInvalidNixIdentifier(const std::string & name)
{
std::smatch match;
if (!std::regex_match(name, match, identifierRegex)) {
warn("This Nix invocation specifies a value for argument '%s' which isn't a valid \
Nix identifier. The project is considering to drop support for this \
or to require quotes around args that aren't valid Nix identifiers. \
If you depend on this behvior, please reach out in \
https://git.lix.systems/lix-project/lix/issues/496 so we can discuss \
your use-case.", name);
}
}
MixEvalArgs::MixEvalArgs()
{
addFlag({
@ -18,7 +34,10 @@ MixEvalArgs::MixEvalArgs()
.description = "Pass the value *expr* as the argument *name* to Nix functions.",
.category = category,
.labels = {"name", "expr"},
.handler = {[&](std::string name, std::string expr) { autoArgs[name] = 'E' + expr; }}
.handler = {[&](std::string name, std::string expr) {
warnInvalidNixIdentifier(name);
autoArgs[name] = 'E' + expr;
}}
});
addFlag({
@ -26,7 +45,10 @@ MixEvalArgs::MixEvalArgs()
.description = "Pass the string *string* as the argument *name* to Nix functions.",
.category = category,
.labels = {"name", "string"},
.handler = {[&](std::string name, std::string s) { autoArgs[name] = 'S' + s; }},
.handler = {[&](std::string name, std::string s) {
warnInvalidNixIdentifier(name);
autoArgs[name] = 'S' + s;
}},
});
addFlag({