lix/src/libexpr/flake/lockfile.hh

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#pragma once
#include "flakeref.hh"
#include <nlohmann/json_fwd.hpp>
namespace nix {
class Store;
}
namespace nix::flake {
Respect lock files of inputs + fine-grained lock file control When computing a lock file, we now respect the lock files of flake inputs. This is important for usability / reproducibility. For example, the 'nixops' flake depends on the 'nixops-aws' and 'nixops-hetzner' repositories. So when the 'nixops' flake is used in another flake, we want the versions of 'nixops-aws' and 'nixops-hetzner' locked by the the 'nixops' flake because those presumably have been tested. This can lead to a proliferation of versions of flakes like 'nixpkgs' (since every flake's lock file could depend on a different version of 'nixpkgs'). This is not a major issue when using Nixpkgs overlays or NixOS modules, since then the top-level flake composes those overlays/modules into *its* version of Nixpkgs and all other versions are ignored. Lock file computation has been made a bit more lazy so it won't try to fetch all those versions of 'nixpkgs'. However, in case it's necessary to minimize flake versions, there now are two input attributes that allow this. First, you can copy an input from another flake, as follows: inputs.nixpkgs.follows = "dwarffs/nixpkgs"; This states that the calling flake's 'nixpkgs' input shall be the same as the 'nixpkgs' input of the 'dwarffs' input. Second, you can override inputs of inputs: inputs.nixpkgs.url = github:edolstra/nixpkgs/<hash>; inputs.nixops.inputs.nixpkgs.url = github:edolstra/nixpkgs/<hash>; or equivalently, using 'follows': inputs.nixpkgs.url = github:edolstra/nixpkgs/<hash>; inputs.nixops.inputs.nixpkgs.follows = "nixpkgs"; This states that the 'nixpkgs' input of the 'nixops' input shall be the same as the calling flake's 'nixpkgs' input. Finally, at '-v' Nix now prints the changes to the lock file, e.g. $ nix flake update ~/Misc/eelco-configurations/hagbard inputs of flake 'git+file:///home/eelco/Misc/eelco-configurations?subdir=hagbard' changed: updated 'nixpkgs': 'github:edolstra/nixpkgs/7845bf5f4b3013df1cf036e9c9c3a55a30331db9' -> 'github:edolstra/nixpkgs/03f3def66a104a221aac8b751eeb7075374848fd' removed 'nixops' removed 'nixops/nixops-aws' removed 'nixops/nixops-hetzner' removed 'nixops/nixpkgs'
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typedef std::vector<FlakeId> InputPath;
struct LockedInput;
/* Lock file information about the dependencies of a flake. */
struct LockedInputs
{
std::map<FlakeId, LockedInput> inputs;
LockedInputs() {};
LockedInputs(const nlohmann::json & json);
nlohmann::json toJson() const;
bool isImmutable() const;
Respect lock files of inputs + fine-grained lock file control When computing a lock file, we now respect the lock files of flake inputs. This is important for usability / reproducibility. For example, the 'nixops' flake depends on the 'nixops-aws' and 'nixops-hetzner' repositories. So when the 'nixops' flake is used in another flake, we want the versions of 'nixops-aws' and 'nixops-hetzner' locked by the the 'nixops' flake because those presumably have been tested. This can lead to a proliferation of versions of flakes like 'nixpkgs' (since every flake's lock file could depend on a different version of 'nixpkgs'). This is not a major issue when using Nixpkgs overlays or NixOS modules, since then the top-level flake composes those overlays/modules into *its* version of Nixpkgs and all other versions are ignored. Lock file computation has been made a bit more lazy so it won't try to fetch all those versions of 'nixpkgs'. However, in case it's necessary to minimize flake versions, there now are two input attributes that allow this. First, you can copy an input from another flake, as follows: inputs.nixpkgs.follows = "dwarffs/nixpkgs"; This states that the calling flake's 'nixpkgs' input shall be the same as the 'nixpkgs' input of the 'dwarffs' input. Second, you can override inputs of inputs: inputs.nixpkgs.url = github:edolstra/nixpkgs/<hash>; inputs.nixops.inputs.nixpkgs.url = github:edolstra/nixpkgs/<hash>; or equivalently, using 'follows': inputs.nixpkgs.url = github:edolstra/nixpkgs/<hash>; inputs.nixops.inputs.nixpkgs.follows = "nixpkgs"; This states that the 'nixpkgs' input of the 'nixops' input shall be the same as the calling flake's 'nixpkgs' input. Finally, at '-v' Nix now prints the changes to the lock file, e.g. $ nix flake update ~/Misc/eelco-configurations/hagbard inputs of flake 'git+file:///home/eelco/Misc/eelco-configurations?subdir=hagbard' changed: updated 'nixpkgs': 'github:edolstra/nixpkgs/7845bf5f4b3013df1cf036e9c9c3a55a30331db9' -> 'github:edolstra/nixpkgs/03f3def66a104a221aac8b751eeb7075374848fd' removed 'nixops' removed 'nixops/nixops-aws' removed 'nixops/nixops-hetzner' removed 'nixops/nixpkgs'
2020-01-24 21:05:11 +00:00
std::optional<LockedInput *> findInput(const InputPath & path);
};
/* Lock file information about a flake input. */
struct LockedInput : LockedInputs
{
FlakeRef ref, originalRef;
Hash narHash;
LockedInput(const FlakeRef & ref, const FlakeRef & originalRef, const Hash & narHash)
: ref(ref), originalRef(originalRef), narHash(narHash)
{ }
LockedInput(const nlohmann::json & json);
bool operator ==(const LockedInput & other) const
{
return
ref == other.ref
&& narHash == other.narHash
&& inputs == other.inputs;
}
nlohmann::json toJson() const;
Path computeStorePath(Store & store) const;
};
/* An entire lock file. Note that this cannot be a FlakeInput for the
top-level flake, because then the lock file would need to contain
the hash of the top-level flake, but committing the lock file
would invalidate that hash. */
struct LockFile : LockedInputs
{
bool operator ==(const LockFile & other) const
{
return inputs == other.inputs;
}
LockFile() {}
LockFile(const nlohmann::json & json) : LockedInputs(json) {}
LockFile(LockedInput && dep)
{
inputs = std::move(dep.inputs);
}
nlohmann::json toJson() const;
static LockFile read(const Path & path);
void write(const Path & path) const;
};
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std::ostream & operator <<(std::ostream & stream, const LockFile & lockFile);
InputPath parseInputPath(std::string_view s);
}