Merge pull request #9 from facet-rs/default-from-struct

fix: Re-implement 'get field values from Default struct'

Author: fasterthanlime

Cargo.lock

@@ -21,13 +21,13 @@ log = ["dep:log"]
 
 [dependencies]
 yaml-rust2 = "0.10.3"
-facet-core = { version = "0.29", default-features = false }
-facet-reflect = { version = "0.29", default-features = false }
+facet-core = { version = "0.29.1", default-features = false }
+facet-reflect = { version = "0.29.1", default-features = false }
 facet-serialize = { version = "0.29", default-features = false, optional = true }
 log = { version = "0.4.27", optional = true }
 
 [dev-dependencies]
-facet = { version = "0.29" }
+facet = { version = "0.29.1" }
 eyre = "0.6.12"
 ulid = "1.2.1"
 time = { version = "0.3.41", features = ["macros", "parsing", "formatting"] }

Cargo.toml

@@ -127,12 +127,19 @@ fn deserialize_value<'facet>(wip: &mut Partial<'facet>, value: &Yaml) -> Result<
                 }
             }
 
+            let mut default_instance: Option<Partial> = None;
+
             for (index, _field) in sd.fields.iter().enumerate() {
                 let is_set = wip.is_field_set(index).map_err(|e| AnyErr(e.to_string()))?;
                 if !is_set {
-                    todo!(
-                        "should fill unset fields from struct's Default, but not implemented yet. the previous implementation was unsound."
-                    )
+                    let default_instance_mut = default_instance.get_or_insert_with(|| {
+                        // FIXME: those unwrap() don't look good
+                        let mut partial = Partial::alloc_shape(shape).unwrap();
+                        // FIXME: this'll blow up if the struct itself doesn't impl Default
+                        partial.set_default().unwrap();
+                        partial
+                    });
+                    wip.steal_nth_field(default_instance_mut, index)?;
                 }
             }
         } else {

src/deserialize/mod.rs

@@ -2,7 +2,6 @@ use facet::Facet;
 use facet_testhelpers::test;
 
 #[test]
-#[ignore]
 fn test_struct_level_default() {
     #[derive(Facet, Default, Debug, PartialEq)]
     #[facet(default)]