Wrap getrandom::Error in uuid::Error for Uuid::new_v4

src/error.rs

@@ -4,12 +4,12 @@ use crate::{builder, parser};
 /// A general error that can occur when working with UUIDs.
 // TODO: improve the doc
 // BODY: This detail should be fine for initial merge
-#[derive(Clone, Debug, Eq, Hash, PartialEq)]
+#[derive(Clone, Debug, Eq, PartialEq)]
 pub struct Error(Inner);
 
 // TODO: write tests for Error
 // BODY: not immediately blocking, but should be covered for 1.0
-#[derive(Clone, Debug, Eq, Hash, PartialEq)]
+#[derive(Clone, Debug, Eq, PartialEq)]
 enum Inner {
     /// An error occurred while handling [`Uuid`] bytes.
     ///
@@ -26,6 +26,12 @@ enum Inner {
     /// [`parser::ParseError`]: parser/enum.ParseError.html
     /// [`Uuid`]: struct.Uuid.html
     Parser(parser::Error),
+
+    #[cfg(feature = "getrandom")]
+    /// An error occurred while getting random bytes.
+    ///
+    /// See [`getrandom::Error`]
+    Random(getrandom::Error),
 }
 
 impl From<builder::Error> for Error {
@@ -40,11 +46,20 @@ impl From<parser::Error> for Error {
     }
 }
 
+#[cfg(feature = "getrandom")]
+impl From<getrandom::Error> for Error {
+    fn from(err: getrandom::Error) -> Self {
+        Error(Inner::Random(err))
+    }
+}
+
 impl fmt::Display for Error {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match self.0 {
             Inner::Build(ref err) => fmt::Display::fmt(&err, f),
             Inner::Parser(ref err) => fmt::Display::fmt(&err, f),
+            #[cfg(feature = "getrandom")]
+            Inner::Random(ref err) => fmt::Display::fmt(&err, f),
         }
     }
 }
@@ -59,6 +74,13 @@ mod std_support {
             match self.0 {
                 Inner::Build(ref err) => Some(err),
                 Inner::Parser(ref err) => Some(err),
+                #[cfg(feature = "getrandom")]
+                // NB: getrandom::Error only impls the Error trait with the
+                // getrandom/std feature which we cannot activate via our std
+                // feature without also activating the optional dependency, even
+                // when not desired (not directly activated). So we just don't
+                // forward the source for now, as the less bad option.
+                Inner::Random(_) => None,
             }
         }
     }

src/v4.rs

@@ -24,8 +24,7 @@ impl Uuid {
     ///
     /// [`getrandom`]: https://crates.io/crates/getrandom
     /// [from_bytes]: struct.Builder.html#method.from_bytes
-    // TODO: change signature to support uuid's Error.
-    pub fn new_v4() -> Result<Uuid, getrandom::Error> {
+    pub fn new_v4() -> Result<Uuid, crate::Error> {
         let mut bytes = [0u8; 16];
         getrandom::getrandom(&mut bytes)?;