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Fix deep overrides #108

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Merged
edolstra merged 4 commits into from
Jun 25, 2025
Merged

Fix deep overrides #108

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a572c94
Fix deep overrides
edolstra Jun 12, 2025
9a18a11
Add tests for deep overrides
edolstra Jun 12, 2025
6999183
Don't allow flake inputs to have both a flakeref and a follows
edolstra Jun 12, 2025
0e352a6
Merge remote-tracking branch 'detsys/detsys-main' into fix-deep-overr…
edolstra Jun 25, 2025
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36 changes: 22 additions & 14 deletions src/libflake/flake.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -85,7 +85,6 @@ static void parseFlakeInputAttr(

static FlakeInput parseFlakeInput(
EvalState & state,
std::string_view inputName,
Value * value,
const PosIdx pos,
const InputAttrPath & lockRootAttrPath,
Expand Down Expand Up @@ -155,8 +154,8 @@ static FlakeInput parseFlakeInput(
input.ref = parseFlakeRef(state.fetchSettings, *url, {}, true, input.isFlake, true);
}

if (!input.follows && !input.ref)
input.ref = FlakeRef::fromAttrs(state.fetchSettings, {{"type", "indirect"}, {"id", std::string(inputName)}});
if (input.ref && input.follows)
throw Error("flake input has both a flake reference and a follows attribute, at %s", state.positions[pos]);

return input;
}
Expand Down Expand Up @@ -185,7 +184,6 @@ static std::pair<std::map<FlakeId, FlakeInput>, fetchers::Attrs> parseFlakeInput
} else {
inputs.emplace(inputName,
parseFlakeInput(state,
inputName,
inputAttr.value,
inputAttr.pos,
lockRootAttrPath,
Expand Down Expand Up @@ -467,18 +465,27 @@ LockedFlake lockFlake(

/* Get the overrides (i.e. attributes of the form
'inputs.nixops.inputs.nixpkgs.url = ...'). */
for (auto & [id, input] : flakeInputs) {
std::function<void(const FlakeInput & input, const InputAttrPath & prefix)> addOverrides;
addOverrides = [&](const FlakeInput & input, const InputAttrPath & prefix)
{
for (auto & [idOverride, inputOverride] : input.overrides) {
auto inputAttrPath(inputAttrPathPrefix);
inputAttrPath.push_back(id);
auto inputAttrPath(prefix);
inputAttrPath.push_back(idOverride);
overrides.emplace(inputAttrPath,
OverrideTarget {
.input = inputOverride,
.sourcePath = sourcePath,
.parentInputAttrPath = inputAttrPathPrefix
});
if (inputOverride.ref || inputOverride.follows)
overrides.emplace(inputAttrPath,
OverrideTarget {
.input = inputOverride,
.sourcePath = sourcePath,
.parentInputAttrPath = inputAttrPathPrefix

@cole-h cole-h Jun 19, 2025

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Should this also be changed to prefix like line 472 above was?

@edolstra edolstra Jun 25, 2025

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I think this is correct because it's the input attr path used to resolve relative path inputs. In an override, these should refer to the attr path of the overriding flake, which is inputAttrPathPrefix.

});
addOverrides(inputOverride, inputAttrPath);
}
};

for (auto & [id, input] : flakeInputs) {
auto inputAttrPath(inputAttrPathPrefix);
inputAttrPath.push_back(id);
addOverrides(input, inputAttrPath);
}

/* Check whether this input has overrides for a
Expand Down Expand Up @@ -534,7 +541,8 @@ LockedFlake lockFlake(
continue;
}

assert(input.ref);
if (!input.ref)
input.ref = FlakeRef::fromAttrs(state.fetchSettings, {{"type", "indirect"}, {"id", std::string(id)}});

auto overridenParentPath =
input.ref->input.isRelative()
Expand Down
71 changes: 71 additions & 0 deletions tests/functional/flakes/follow-paths.sh
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Original file line number Diff line number Diff line change
Expand Up @@ -359,3 +359,74 @@ rm "$flakeFollowsCustomUrlA"/flake.lock
json=$(nix flake metadata "$flakeFollowsCustomUrlA" --override-input B/C "$flakeFollowsCustomUrlD" --json)
echo "$json" | jq .locks.nodes.C.original
[[ $(echo "$json" | jq -r .locks.nodes.C.original.path) = './flakeC' ]]

# Test deep overrides, e.g. `inputs.B.inputs.C.inputs.D.follows = ...`.

cat <<EOF > $flakeFollowsD/flake.nix
{ outputs = _: {}; }
EOF
cat <<EOF > $flakeFollowsC/flake.nix
{
inputs.D.url = "path:nosuchflake";
outputs = _: {};
}
EOF
cat <<EOF > $flakeFollowsB/flake.nix
{
inputs.C.url = "path:$flakeFollowsC";
outputs = _: {};
}
EOF
cat <<EOF > $flakeFollowsA/flake.nix
{
inputs.B.url = "path:$flakeFollowsB";
inputs.D.url = "path:$flakeFollowsD";
inputs.B.inputs.C.inputs.D.follows = "D";
outputs = _: {};
}
EOF

nix flake lock $flakeFollowsA

[[ $(jq -c .nodes.C.inputs.D $flakeFollowsA/flake.lock) = '["D"]' ]]

# Test overlapping flake follows: B has D follow C/D, while A has B/C follow C

cat <<EOF > $flakeFollowsC/flake.nix
{
inputs.D.url = "path:$flakeFollowsD";
outputs = _: {};
}
EOF
cat <<EOF > $flakeFollowsB/flake.nix
{
inputs.C.url = "path:nosuchflake";
inputs.D.follows = "C/D";
outputs = _: {};
}
EOF
cat <<EOF > $flakeFollowsA/flake.nix
{
inputs.B.url = "path:$flakeFollowsB";
inputs.C.url = "path:$flakeFollowsC";
inputs.B.inputs.C.follows = "C";
outputs = _: {};
}
EOF

# bug was not triggered without recreating the lockfile
nix flake lock $flakeFollowsA --recreate-lock-file

[[ $(jq -c .nodes.B.inputs.D $flakeFollowsA/flake.lock) = '["B","C","D"]' ]]

# Check that you can't have both a flakeref and a follows attribute on an input.
cat <<EOF > $flakeFollowsB/flake.nix
{
inputs.C.url = "path:nosuchflake";
inputs.D.url = "path:nosuchflake";
inputs.D.follows = "C/D";
outputs = _: {};
}
EOF

expectStderr 1 nix flake lock $flakeFollowsA --recreate-lock-file | grepQuiet "flake input has both a flake reference and a follows attribute"