test: Mark receive_imf() as only for tests and "internals" feature (#6235)

`receive_imf() is only used in tests and the REPL, which enables the
"internals" feature. This PR marks it as such, so that it's clear not
only from the comment that this function is not used for anything else.

Author: Hocuri

src/receive_imf.rs

@@ -6,7 +6,7 @@ use std::str::FromStr;
 use anyhow::{Context as _, Result};
 use deltachat_contact_tools::{addr_cmp, may_be_valid_addr, sanitize_single_line, ContactAddress};
 use iroh_gossip::proto::TopicId;
-use mailparse::{parse_mail, SingleInfo};
+use mailparse::SingleInfo;
 use num_traits::FromPrimitive;
 use once_cell::sync::Lazy;
 use regex::Regex;
@@ -73,12 +73,13 @@ pub struct ReceivedMsg {
 ///
 /// This method returns errors on a failure to parse the mail or extract Message-ID. It's only used
 /// for tests and REPL tool, not actual message reception pipeline.
+#[cfg(any(test, feature = "internals"))]
 pub async fn receive_imf(
     context: &Context,
     imf_raw: &[u8],
     seen: bool,
 ) -> Result<Option<ReceivedMsg>> {
-    let mail = parse_mail(imf_raw).context("can't parse mail")?;
+    let mail = mailparse::parse_mail(imf_raw).context("can't parse mail")?;
     let rfc724_mid =
         imap::prefetch_get_message_id(&mail.headers).unwrap_or_else(imap::create_message_id);
     if let Some(download_limit) = context.download_limit().await? {
@@ -105,6 +106,7 @@ pub async fn receive_imf(
 /// Emulates reception of a message from "INBOX".
 ///
 /// Only used for tests and REPL tool, not actual message reception pipeline.
+#[cfg(any(test, feature = "internals"))]
 pub(crate) async fn receive_imf_from_inbox(
     context: &Context,
     rfc724_mid: &str,

src/securejoin.rs

@@ -244,10 +244,10 @@ async fn verify_sender_by_fingerprint(
 
 /// What to do with a Secure-Join handshake message after it was handled.
 ///
-/// This status is returned to [`receive_imf`] which will use it to decide what to do
+/// This status is returned to [`receive_imf_inner`] which will use it to decide what to do
 /// next with this incoming setup-contact/secure-join handshake message.
 ///
-/// [`receive_imf`]: crate::receive_imf::receive_imf
+/// [`receive_imf_inner`]: crate::receive_imf::receive_imf_inner
 #[derive(Debug, PartialEq, Eq)]
 pub(crate) enum HandshakeMessage {
     /// The message has been fully handled and should be removed/delete.