Remove upper limit on the attachment size

Recommended file size is used for recoding media.
For the upper size, we rely on the provider to tell us back
if the message cannot be delivered to some recipients.
This allows to send large files, such as APKs,
when using providers that don't have such strict limits.

CHANGELOG.md

@@ -3,6 +3,7 @@
 ## [Unreleased]
 
 ### Changes
+- Remove upper limit on the attachment size. #4253
 
 ### Fixes
 

src/mimefactory.rs

@@ -27,16 +27,13 @@ use crate::simplify::escape_message_footer_marks;
 use crate::stock_str;
 use crate::tools::IsNoneOrEmpty;
 use crate::tools::{
-    create_outgoing_rfc724_mid, create_smeared_timestamp, get_filebytes, remove_subject_prefix,
-    time,
+    create_outgoing_rfc724_mid, create_smeared_timestamp, remove_subject_prefix, time,
 };
 
 // attachments of 25 mb brutto should work on the majority of providers
 // (brutto examples: web.de=50, 1&1=40, t-online.de=32, gmail=25, posteo=50, yahoo=25, all-inkl=100).
-// as an upper limit, we double the size; the core won't send messages larger than this
 // to get the netto sizes, we subtract 1 mb header-overhead and the base64-overhead.
 pub const RECOMMENDED_FILE_SIZE: u64 = 24 * 1024 * 1024 / 4 * 3;
-const UPPER_LIMIT_FILE_SIZE: u64 = 49 * 1024 * 1024 / 4 * 3;
 
 #[derive(Debug, Clone)]
 pub enum Loaded {
@@ -1211,15 +1208,8 @@ impl<'a> MimeFactory<'a> {
 
         // add attachment part
         if self.msg.viewtype.has_file() {
-            if !is_file_size_okay(context, self.msg).await? {
-                bail!(
-                    "Message exceeds the recommended {} MB.",
-                    RECOMMENDED_FILE_SIZE / 1_000_000,
-                );
-            } else {
-                let (file_part, _) = build_body_file(context, self.msg, "").await?;
-                parts.push(file_part);
-            }
+            let (file_part, _) = build_body_file(context, self.msg, "").await?;
+            parts.push(file_part);
         }
 
         if let Some(meta_part) = meta_part {
@@ -1483,16 +1473,6 @@ fn recipients_contain_addr(recipients: &[(String, String)], addr: &str) -> bool
         .any(|(_, cur)| cur.to_lowercase() == addr_lc)
 }
 
-async fn is_file_size_okay(context: &Context, msg: &Message) -> Result<bool> {
-    match msg.param.get_path(Param::File, context)? {
-        Some(path) => {
-            let bytes = get_filebytes(context, &path).await?;
-            Ok(bytes <= UPPER_LIMIT_FILE_SIZE)
-        }
-        None => Ok(false),
-    }
-}
-
 fn render_rfc724_mid(rfc724_mid: &str) -> String {
     let rfc724_mid = rfc724_mid.trim().to_string();