diff --git a/lib/attrsets.nix b/lib/attrsets.nix index bf6c90bf1be6..14ce9c257731 100644 --- a/lib/attrsets.nix +++ b/lib/attrsets.nix @@ -883,7 +883,10 @@ rec { recursiveUpdateUntil (path: lhs: rhs: !(isAttrs lhs && isAttrs rhs)) lhs rhs; - /* Returns true if the pattern is contained in the set. False otherwise. + /* + Recurse into every attribute set of the first argument and check that: + - Each attribute path also exists in the second argument. + - If the attribute's value is not a nested attribute set, it must have the same value in the right argument. Example: matchAttrs { cpu = {}; } { cpu = { bits = 64; }; } @@ -895,16 +898,24 @@ rec { matchAttrs = # Attribute set structure to match pattern: - # Attribute set to find patterns in + # Attribute set to check attrs: assert isAttrs pattern; - all id (attrValues (zipAttrsWithNames (attrNames pattern) (n: values: - let pat = head values; val = elemAt values 1; in - if length values == 1 then false - else if isAttrs pat then isAttrs val && matchAttrs pat val - else pat == val - ) [pattern attrs])); - + all + ( # Compare equality between `pattern` & `attrs`. + attr: + # Missing attr, not equal. + attrs ? ${attr} && ( + let + lhs = pattern.${attr}; + rhs = attrs.${attr}; + in + # If attrset check recursively + if isAttrs lhs then isAttrs rhs && matchAttrs lhs rhs + else lhs == rhs + ) + ) + (attrNames pattern); /* Override only the attributes that are already present in the old set useful for deep-overriding. diff --git a/lib/tests/misc.nix b/lib/tests/misc.nix index 06cb5e763e2c..57c1be4a2073 100644 --- a/lib/tests/misc.nix +++ b/lib/tests/misc.nix @@ -831,6 +831,26 @@ runTests { }; }; + testMatchAttrsMatchingExact = { + expr = matchAttrs { cpu = { bits = 64; }; } { cpu = { bits = 64; }; }; + expected = true; + }; + + testMatchAttrsMismatch = { + expr = matchAttrs { cpu = { bits = 128; }; } { cpu = { bits = 64; }; }; + expected = false; + }; + + testMatchAttrsMatchingImplicit = { + expr = matchAttrs { cpu = { }; } { cpu = { bits = 64; }; }; + expected = true; + }; + + testMatchAttrsMissingAttrs = { + expr = matchAttrs { cpu = {}; } { }; + expected = false; + }; + testOverrideExistingEmpty = { expr = overrideExisting {} { a = 1; }; expected = {};