nixos/nix
1
1
Fork 0
mirror of https://github.com/NixOS/nix.git synced 2025-11-13 14:02:42 +01:00
Code Activity

Restore input substitution

Browse source 
The ability to substitute inputs was removed in #10612 because it was
broken: with user-specified inputs containing a `narHash` attribute,
substitution resulted in an input that lacked the attributes returned
by the real fetcher (such as `lastModified`).

To fix this, we introduce a new input attribute `final`. If `final =
true`, fetching the input cannot add or change any attributes.

We only attempt to substitute inputs that have `final = true`. This is
implied by lock file entries; we only write a lock file if all its
entries are "final".

The user can specified `final = true` in `fetchTree`, in which case it
is their responsibility to ensure that all attributes returned by the
fetcher are included in the `fetchTree` call. For example,

  nix eval --impure --expr 'builtins.fetchTree { type = "github"; owner = "NixOS"; repo = "patchelf"; final = true; narHash = "sha256-FSoxTcRZMGHNJh8dNtKOkcUtjhmhU6yQXcZZfUPLhQM="; }'

succeeds in a store path with the specified NAR hash exists or is
substitutable, but fails with

  error: fetching final input '{"final":true,"narHash":"sha256-FSoxTcRZMGHNJh8dNtKOkcUtjhmhU6yQXcZZfUPLhQM=","owner":"NixOS","repo":"patchelf","type":"github"}' resulted in different input '{"final":true,"lastModified":1718457448,"narHash":"sha256-FSoxTcRZMGHNJh8dNtKOkcUtjhmhU6yQXcZZfUPLhQM=","owner":"NixOS","repo":"patchelf","rev":"a0f54334df36770b335c051e540ba40afcbf8378","type":"github"}'
This commit is contained in:
Eelco Dolstra 2024-10-15 20:55:05 +02:00
parent 806a91f7bf
commit 188d97e1f1
7 changed files with 79 additions and 21 deletions
Download patch file Download diff file Expand all files Collapse all files

1
src/libflake/flake/flake.cc
View file

@ -85,7 +85,6 @@ static void forceTrivialValue(EvalState & state, Value & value, const PosIdx pos
state.forceValue(value, pos);
}
static void expectType(EvalState & state, ValueType type,
Value & value, const PosIdx pos)
{

12
src/libflake/flake/lockfile.cc
View file

@ -46,6 +46,10 @@ LockedNode::LockedNode(
if (!lockedRef.input.isLocked())
throw Error("lock file contains unlocked input '%s'",
fetchers::attrsToJSON(lockedRef.input.toAttrs()));
// For backward compatibility, lock file entries are implicitly final.
assert(!lockedRef.input.attrs.contains("final"));
lockedRef.input.attrs.insert_or_assign("final", Explicit<bool>(true));
}
StorePath LockedNode::computeStorePath(Store & store) const
@ -53,7 +57,6 @@ StorePath LockedNode::computeStorePath(Store & store) const
return lockedRef.input.computeStorePath(store);
}
static std::shared_ptr<Node> doFind(const ref<Node> & root, const InputPath & path, std::vector<InputPath> & visited)
{
auto pos = root;
@ -191,6 +194,11 @@ std::pair<nlohmann::json, LockFile::KeyMap> LockFile::toJSON() const
if (auto lockedNode = node.dynamic_pointer_cast<const LockedNode>()) {
n["original"] = fetchers::attrsToJSON(lockedNode->originalRef.toAttrs());
n["locked"] = fetchers::attrsToJSON(lockedNode->lockedRef.toAttrs());
/* For backward compatibility, omit the "final"
attribute. We never allow non-final inputs in lock files
anyway. */
assert(lockedNode->lockedRef.input.isFinal());
n["locked"].erase("final");
if (!lockedNode->isFlake)
n["flake"] = false;
}
@ -239,7 +247,7 @@ std::optional<FlakeRef> LockFile::isUnlocked() const
for (auto & i : nodes) {
if (i == ref<const Node>(root)) continue;
auto node = i.dynamic_pointer_cast<const LockedNode>();
if (node && !node->lockedRef.input.isLocked())
if (node && (!node->lockedRef.input.isLocked() || !node->lockedRef.input.isFinal()))
return node->lockedRef;
}

4
src/libflake/flake/lockfile.hh
View file

@ -68,8 +68,8 @@ struct LockFile
std::pair<std::string, KeyMap> to_string() const;
/**
* Check whether this lock file has any unlocked inputs. If so,
* return one.
* Check whether this lock file has any unlocked or non-final
* inputs. If so, return one.
*/
std::optional<FlakeRef> isUnlocked() const;