openpgp: Improve error message.

  - When an algorithm is completely disabled, don't say that it
    "is not considered secure since 1970-01-01T00:00:00Z" (i.e., the
    unix epoch), just say "is not considered secure".

  - Fixes #1000.

1 files changed, 7 insertions, 1 deletions

diff --git a/openpgp/src/lib.rs b/openpgp/src/lib.rs
index a949403a..6f792c88 100644
--- a/openpgp/src/lib.rs
+++ b/openpgp/src/lib.rs
@@ -336,7 +336,13 @@ pub enum Error {
     /// The optional time is the time at which the operation was
     /// determined to no longer be secure.
     #[error("{0} is not considered secure{}",
-            .1.as_ref().map(|t| format!(" since {}", crate::fmt::time(t)))
+            .1.as_ref().map(|t| {
+                if *t == std::time::UNIX_EPOCH {
+                    "".to_string()
+                } else {
+                    format!(" since {}", crate::fmt::time(t))
+                }
+            })
             .unwrap_or_else(|| "".into()))]
     PolicyViolation(String, Option<std::time::SystemTime>),
 }