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//! This module implements the ratchet checks, see ../README.md#ratchet-checks
//!
//! Each type has a `compare` method that validates the ratchet checks for that item.
use crate::nixpkgs_problem::NixpkgsProblem;
use crate::structure;
use crate::validation::{self, Validation, Validation::Success};
use std::collections::HashMap;
use std::path::PathBuf;
/// The ratchet value for the entirety of Nixpkgs.
#[derive(Default)]
pub struct Nixpkgs {
/// Sorted list of packages in package_map
pub package_names: Vec<String>,
/// The ratchet values for all packages
pub package_map: HashMap<String, Package>,
}
impl Nixpkgs {
/// Validates the ratchet checks for Nixpkgs
pub fn compare(from: Self, to: Self) -> Validation<()> {
validation::sequence_(
// We only loop over the current attributes,
// we don't need to check ones that were removed
to.package_names.into_iter().map(|name| {
Package::compare(&name, from.package_map.get(&name), &to.package_map[&name])
}),
)
}
}
/// The ratchet value for a top-level package
pub struct Package {
/// The ratchet value for the check for non-auto-called empty arguments
pub empty_non_auto_called: RatchetState<EmptyNonAutoCalled>,
/// The ratchet value for the check for new packages using pkgs/by-name
pub uses_by_name: RatchetState<UsesByName>,
}
impl Package {
/// Validates the ratchet checks for a top-level package
pub fn compare(name: &str, optional_from: Option<&Self>, to: &Self) -> Validation<()> {
validation::sequence_([
RatchetState::<EmptyNonAutoCalled>::compare(
name,
optional_from.map(|x| &x.empty_non_auto_called),
&to.empty_non_auto_called,
),
RatchetState::<UsesByName>::compare(
name,
optional_from.map(|x| &x.uses_by_name),
&to.uses_by_name,
),
])
}
}
/// The ratchet state of a generic ratchet check.
pub enum RatchetState<Context> {
/// The ratchet is loose, it can be tightened more.
/// In other words, this is the legacy state we're trying to move away from.
/// Introducing new instances is not allowed but previous instances will continue to be allowed.
/// The `Context` is context for error messages in case a new instance of this state is
/// introduced
Loose(Context),
/// The ratchet is tight, it can't be tightened any further.
/// This is either because we already use the latest state, or because the ratchet isn't
/// relevant.
Tight,
}
/// A trait that can convert an attribute-specific error context into a NixpkgsProblem
pub trait ToNixpkgsProblem {
/// How to convert an attribute-specific error context into a NixpkgsProblem
fn to_nixpkgs_problem(name: &str, context: &Self, existed_before: bool) -> NixpkgsProblem;
}
impl<Context: ToNixpkgsProblem> RatchetState<Context> {
/// Compare the previous ratchet state of an attribute to the new state.
/// The previous state may be `None` in case the attribute is new.
fn compare(name: &str, optional_from: Option<&Self>, to: &Self) -> Validation<()> {
// If we don't have a previous state, enforce a tight ratchet
let from = optional_from.unwrap_or(&RatchetState::Tight);
match (from, to) {
// Always okay to keep it tight or tighten the ratchet
(_, RatchetState::Tight) => Success(()),
// Grandfathering policy for a loose ratchet
(RatchetState::Loose { .. }, RatchetState::Loose { .. }) => Success(()),
// Loosening a ratchet is now allowed
(RatchetState::Tight, RatchetState::Loose(context)) => {
Context::to_nixpkgs_problem(name, context, optional_from.is_some()).into()
}
}
}
}
/// The ratchet value of an attribute
/// for the non-auto-called empty argument check of a single.
///
/// This checks that packages defined in `pkgs/by-name` cannot be overridden
/// with an empty second argument like `callPackage ... { }`.
pub struct EmptyNonAutoCalled;
impl ToNixpkgsProblem for EmptyNonAutoCalled {
fn to_nixpkgs_problem(name: &str, _context: &Self, _existed_before: bool) -> NixpkgsProblem {
NixpkgsProblem::WrongCallPackage {
relative_package_file: structure::relative_file_for_package(name),
package_name: name.to_owned(),
}
}
}
/// The ratchet value of an attribute
/// for the check that new packages use pkgs/by-name
///
/// This checks that all new package defined using callPackage must be defined via pkgs/by-name
/// It also checks that once a package uses pkgs/by-name, it can't switch back to all-packages.nix
#[derive(Clone)]
pub struct UsesByName {
/// The first callPackage argument, used for better errors
pub call_package_path: Option<PathBuf>,
/// Whether the second callPackage argument is empty, used for better errors
pub empty_arg: bool,
}
impl ToNixpkgsProblem for UsesByName {
fn to_nixpkgs_problem(name: &str, a: &Self, existed_before: bool) -> NixpkgsProblem {
if existed_before {
NixpkgsProblem::MovedOutOfByName {
package_name: name.to_owned(),
call_package_path: a.call_package_path.clone(),
empty_arg: a.empty_arg,
}
} else {
NixpkgsProblem::NewPackageNotUsingByName {
package_name: name.to_owned(),
call_package_path: a.call_package_path.clone(),
empty_arg: a.empty_arg,
}
}
}
}
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