diff options
5 files changed, 29 insertions, 0 deletions
diff --git a/tvix/eval/src/builtins/mod.rs b/tvix/eval/src/builtins/mod.rs index e19de96158..a9d04ba7c3 100644 --- a/tvix/eval/src/builtins/mod.rs +++ b/tvix/eval/src/builtins/mod.rs @@ -359,6 +359,15 @@ mod pure_builtins { #[builtin("toJSON")] async fn builtin_to_json(co: GenCo, val: Value) -> Result<Value, ErrorKind> { + if let Value::Attrs(attrs) = &val { + // Attribute sets with a callable `__toString` attribute + // serialise to the string-coerced version of the result of + // calling that. + if let Some(s) = attrs.try_to_string(&co, CoercionKind::Weak).await { + return Ok(Value::String(serde_json::to_string(&s)?.into())); + } + } + // All thunks need to be evaluated before serialising, as the // data structure is fully traversed by the Serializer. let val = generators::request_deep_force(&co, val, SharedThunkSet::default()).await; diff --git a/tvix/eval/src/tests/tvix_tests/eval-fail-builtins-tojson-tostring-notcallable.nix b/tvix/eval/src/tests/tvix_tests/eval-fail-builtins-tojson-tostring-notcallable.nix new file mode 100644 index 0000000000..345b76fde0 --- /dev/null +++ b/tvix/eval/src/tests/tvix_tests/eval-fail-builtins-tojson-tostring-notcallable.nix @@ -0,0 +1,5 @@ +# attribute sets with a non-callable `__toString` can not be +# serialised to JSON. +builtins.toJSON { + __toString = 42; +} diff --git a/tvix/eval/src/tests/tvix_tests/eval-fail-builtins-tojson-tostring-strong.nix b/tvix/eval/src/tests/tvix_tests/eval-fail-builtins-tojson-tostring-strong.nix new file mode 100644 index 0000000000..d1c72dc678 --- /dev/null +++ b/tvix/eval/src/tests/tvix_tests/eval-fail-builtins-tojson-tostring-strong.nix @@ -0,0 +1,6 @@ +# String coercions when using builtins.toJSON on an attribute set with +# a `__toString` attribute should be weak. +builtins.toJSON { + __toString = self: self.x; + x = 42; +} diff --git a/tvix/eval/src/tests/tvix_tests/eval-okay-builtins-tojson-tostring.exp b/tvix/eval/src/tests/tvix_tests/eval-okay-builtins-tojson-tostring.exp new file mode 100644 index 0000000000..2661fd257b --- /dev/null +++ b/tvix/eval/src/tests/tvix_tests/eval-okay-builtins-tojson-tostring.exp @@ -0,0 +1 @@ +"\"it's 42\"" diff --git a/tvix/eval/src/tests/tvix_tests/eval-okay-builtins-tojson-tostring.nix b/tvix/eval/src/tests/tvix_tests/eval-okay-builtins-tojson-tostring.nix new file mode 100644 index 0000000000..ec6f8d947c --- /dev/null +++ b/tvix/eval/src/tests/tvix_tests/eval-okay-builtins-tojson-tostring.nix @@ -0,0 +1,8 @@ +# Attribute sets with a `__toString` attribute JSON-serialise with a +# string coercion of the function call result. + +builtins.toJSON { + __toString = self: "it's " + (builtins.toString (self.x * self.y)); + x = 21; + y = 2; +} |