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refact: Make require_attrs_select* error handling regular

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(cherry picked from commit de6c6cbd462202405bc787fed02dee249cf16973)
This commit is contained in:
Robert Hensing 2024-06-14 18:21:13 +02:00
parent 61efb9b79f
commit c16a9b0595
2 changed files with 56 additions and 32 deletions
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56
rust/nix-expr/src/eval_state.rs
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@ -184,20 +184,27 @@ impl EvalState {
Ok(attrs)
}
// TODO: make this the main implementation and move the error handling to require_attrs_select_opt
// that gets rid of the odd self.context.check_err() usage that relies on the context not being reset
/// Evaluate, require that the value is an attrset, and select an attribute by name.
pub fn require_attrs_select(&self, v: &Value, attr_name: &str) -> Result<Value> {
let r = self.require_attrs_select_opt(v, attr_name)?;
match r {
Some(v) => Ok(v),
None => self.context.check_err().and_then(|_| {
// should be unreachable
bail!("attribute not found: {}", attr_name)
}),
let t = self.value_type(v)?;
if t != ValueType::AttrSet {
bail!("expected an attrset, but got a {:?}", t);
}
let attr_name = CString::new(attr_name)
.with_context(|| "require_attrs_select: attrName contains null byte")?;
let v2 = self.context.check_one_call(|ctx_ptr| unsafe {
raw::get_attr_byname(ctx_ptr, v.raw_ptr(), self.raw_ptr(), attr_name.as_ptr())
})?;
Ok(Value::new(v2))
}
/// Evaluate, require that the value is an attrset, and select an attribute by name.
///
/// Return `Err(...)` if `v` is not an attrset, or if some other error occurred.
///
/// Return `Ok(None)` if the attribute is not present.
///
/// Return `Ok(Some(value))` if the attribute is present.
pub fn require_attrs_select_opt(&self, v: &Value, attr_name: &str) -> Result<Option<Value>> {
let t = self.value_type(v)?;
if t != ValueType::AttrSet {
@ -205,21 +212,10 @@ impl EvalState {
}
let attr_name = CString::new(attr_name)
.with_context(|| "require_attrs_select_opt: attrName contains null byte")?;
// c_void should be Value; why was void generated?
let v = unsafe {
raw::get_attr_byname(
self.context.ptr(),
v.raw_ptr(),
self.raw_ptr(),
attr_name.as_ptr(),
)
};
if self.context.is_key_error() {
Ok(None)
} else {
self.context.check_err()?;
Ok(Some(Value::new(v)))
}
let v2 = self.context.check_one_call_or_key_none(|ctx_ptr| unsafe {
raw::get_attr_byname(ctx_ptr, v.raw_ptr(), self.raw_ptr(), attr_name.as_ptr())
})?;
Ok(v2.map(Value::new))
}
/// Create a new value containing the passed string.
@ -575,6 +571,18 @@ mod tests {
let b = es.require_attrs_select(&v, "b").unwrap();
assert_eq!(es.require_string(&a).unwrap(), "aye");
assert_eq!(es.require_string(&b).unwrap(), "bee");
let missing = es.require_attrs_select(&v, "c");
match missing {
Ok(_) => panic!("expected an error"),
Err(e) => {
let s = format!("{e:#}");
// TODO: bad error message from Nix
if !s.contains("missing attribute") {
eprintln!("unexpected error message: {}", s);
assert!(false);
}
}
}
})
.unwrap()
}