(Breaking Change) remove unnecessary Option wrapper on `Error::last…

…_error`.

src/call.rs

@@ -44,9 +44,7 @@ pub fn c_try(ret: libc::c_int) -> Result<libc::c_int, Error> {
 }
 
 pub fn last_error(code: libc::c_int) -> Error {
-    // nowadays this unwrap is safe as `Error::last_error` always returns
-    // `Some`.
-    Error::last_error(code).unwrap()
+    Error::last_error(code)
 }
 
 mod impls {

src/error.rs

@@ -32,12 +32,7 @@ impl Error {
     ///
     /// The `code` argument typically comes from the return value of a function
     /// call. This code will later be returned from the `code` function.
-    ///
-    /// Historically this function returned `Some` or `None` based on the return
-    /// value of `git_error_last` but nowadays it always returns `Some` so it's
-    /// safe to unwrap the return value. This API will change in the next major
-    /// version.
-    pub fn last_error(code: c_int) -> Option<Error> {
+    pub fn last_error(code: c_int) -> Error {
         crate::init();
         unsafe {
             // Note that whenever libgit2 returns an error any negative value
@@ -64,7 +59,7 @@ impl Error {
                 Error::from_raw(code, ptr)
             };
             raw::git_error_clear();
-            Some(err)
+            err
         }
     }
 

src/indexer.rs

@@ -190,7 +190,7 @@ impl io::Write for Indexer<'_> {
             if res < 0 {
                 Err(io::Error::new(
                     io::ErrorKind::Other,
-                    Error::last_error(res).unwrap(),
+                    Error::last_error(res),
                 ))
             } else {
                 Ok(buf.len())

src/odb.rs

@@ -458,7 +458,7 @@ impl<'repo> OdbPackwriter<'repo> {
             };
 
             if res < 0 {
-                Err(Error::last_error(res).unwrap())
+                Err(Error::last_error(res))
             } else {
                 Ok(res)
             }

src/repo.rs

@@ -848,7 +848,7 @@ impl Repository {
             match value {
                 0 => Ok(false),
                 1 => Ok(true),
-                _ => Err(Error::last_error(value).unwrap()),
+                _ => Err(Error::last_error(value)),
             }
         }
     }

src/tracing.rs

@@ -76,8 +76,7 @@ pub fn trace_set(level: TraceLevel, cb: TracingCb) -> Result<(), Error> {
     let return_code: c_int = unsafe { raw::git_trace_set(level.raw(), Some(tracing_cb_c)) };
 
     if return_code != 0 {
-        // Unwrap here is fine since `Error::last_error` always returns `Some`.
-        Err(Error::last_error(return_code).unwrap())
+        Err(Error::last_error(return_code))
     } else {
         Ok(())
     }