openpgp: Don't finalize the Encryptor in Drop.

  - Previously, Encryptor::drop made an effort to finalize the filter.
    This, however, is only a best-effort mechanism: It cannot report
    errors.

  - Because of this, we now believe that it actually exacerbates the
    problem of downstream users not finalizing the filter: It will
    work most of the time, but sometimes fail.

1 files changed, 5 insertions, 6 deletions

diff --git a/openpgp/src/serialize/stream.rs b/openpgp/src/serialize/stream.rs
index 0a6c0851..a913684a 100644
--- a/openpgp/src/serialize/stream.rs
+++ b/openpgp/src/serialize/stream.rs
@@ -1770,6 +1770,11 @@ impl<'a> Recipient<'a> {
 /// will be encrypted using the given passwords, and for all given
 /// recipients.
 pub struct Encryptor<'a> {
+    // XXX: Opportunity for optimization.  Previously, this writer
+    // implemented `Drop`, so we could not move the inner writer out
+    // of this writer.  We therefore wrapped it with `Option` so that
+    // we can `take()` it.  This writer no longer implements Drop, so
+    // we could avoid the Option here.
     inner: Option<writer::BoxStack<'a, Cookie>>,
     recipients: Vec<Recipient<'a>>,
     passwords: Vec<Password>,
@@ -2314,12 +2319,6 @@ impl<'a> Encryptor<'a> {
     }
 }
 
-impl<'a> Drop for Encryptor<'a> {
-    fn drop(&mut self) {
-        let _ = self.emit_mdc();
-    }
-}
-
 impl<'a> fmt::Debug for Encryptor<'a> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         f.debug_struct("Encryptor")