Update toml to 0.8

Cargo.toml

@@ -30,7 +30,7 @@ confique-macro = { version = "=0.0.9", path = "macro" }
 json5 = { version = "0.4.1", optional = true }
 serde = { version = "1", features = ["derive"] }
 serde_yaml = { version = "0.9", optional = true }
-toml = { version = "0.5", optional = true }
+toml = { version = "0.8", optional = true }
 
 [dev-dependencies]
 pretty_assertions = "1.2.1"

src/file.rs

@@ -77,8 +77,10 @@ impl File {
 
         match self.format {
             #[cfg(feature = "toml")]
-            FileFormat::Toml => toml::from_slice(&file_content)
-                .map_err(|e| error(Box::new(e))),
+            FileFormat::Toml => {
+                let s = std::str::from_utf8(&file_content).map_err(|e| error(Box::new(e)))?;
+                toml::from_str(s).map_err(|e| error(Box::new(e)))
+            }
 
             #[cfg(feature = "yaml")]
             FileFormat::Yaml => serde_yaml::from_slice(&file_content)

src/meta.rs

@@ -140,6 +140,15 @@ impl From<MapKey> for Expr {
     }
 }
 
+impl Float {
+    pub(crate) fn is_nan(&self) -> bool {
+        match self {
+            Float::F32(f) => f.is_nan(),
+            Float::F64(f) => f.is_nan(),
+        }
+    }
+}
+
 fn serialize_map<S>(map: &&'static [MapEntry], serializer: S) -> Result<S::Ok, S::Error>
 where
     S: serde::Serializer,

src/toml.rs

@@ -189,11 +189,20 @@ impl fmt::Display for PrintExpr<'_> {
                 Ok(())
             },
 
+            // We special case floats as the TOML serializer below doesn't work
+            // well with floats, not rounding them appropriately. See:
+            // https://github.com/toml-rs/toml/issues/494
+            //
+            // For all non-NAN floats, the `Display` output is compatible with
+            // TOML.
+            Expr::Float(fv) if !fv.is_nan() => fv.fmt(f),
+
             // All these other types can simply be serialized as is.
             Expr::Str(_) | Expr::Float(_) | Expr::Integer(_) | Expr::Bool(_) | Expr::Array(_) => {
-                toml::to_string(&self.0)
-                    .expect("string serialization to TOML failed")
-                    .fmt(f)
+                let mut s = String::new();
+                serde::Serialize::serialize(&self.0, toml::ser::ValueSerializer::new(&mut s))
+                    .expect("string serialization to TOML failed");
+                s.fmt(f)
             }
         }
     }