[exim] localhost instead of real domain used

Dear Exim folks,


I upgraded from Exim 4.92 to 4.94, and now my formerly working
configuration with the mailing list manager Sympa fails.

I already updated to using non-tainted data

```
diff --git a/exim4/conf.d/router/110_local-config_sympa 
b/exim4/conf.d/router/110_local-config_sympa
index 44bd8fa..b53fb73 100644
--- a/exim4/conf.d/router/110_local-config_sympa
+++ b/exim4/conf.d/router/110_local-config_sympa
@@ -10,8 +10,9 @@ sympa_aliases:
  sympa_router:
    driver = accept
    domains = +sympa_domains
+  local_parts = dsearch,ret=full;/var/lib/sympa/expl/$domain_data
    require_files = +SYMPA_HOME/expl/$domain/$local_part/config
-  condition = ${if 
eqi{${lookup{status}lsearch{SYMPA_HOME/expl/$domain/$local_part/config}}}{open}{yes}{no}}
+  condition = ${if 
eqi{${lookup{status}lsearch{SYMPA_HOME/expl/$domain_data/$local_part_data/config}}}{open}{yes}{no}}
    user = sympa
    local_part_suffix_optional
    local_part_suffix = -request : -editor : \
@@ -21,8 +22,9 @@ sympa_router:
  sympaowner_router:
    driver = accept
    domains = +sympa_domains
+  local_parts = dsearch,ret=full;/var/lib/sympa/expl/$domain_data
    require_files = +SYMPA_HOME/expl/$domain/$local_part/config
-  condition = ${if 
eqi{${lookup{status}lsearch{SYMPA_HOME/expl/$domain/$local_part/config}}}{open}{yes}{no}}
+  condition = ${if 
eqi{${lookup{status}lsearch{SYMPA_HOME/expl/$domain_data/$local_part_data/config}}}{open}{yes}{no}}
    user = sympa
    local_part_suffix_optional
    local_part_suffix = -owner : -owner+*
```

But now I am stuck with:

```
2021-04-04 21:01:52.507 [22134] 1lT9sW-0005l0-1q <= mylist-owner@???
U=sympa P=local S=1584 M8S=0 RT=0.193s
id=d9c25490-6e5d-472f-3bea-6dd073d63135@??? from
<mylist-owner@???> for user@??? user2@???
2021-04-04 21:01:52.530 [22135] 1lT9sW-0005l0-1q failed to open
/var/lib/sympa/expl/localhost for directory search: No such file or
directory
```

`mylist` is a directory in `/var/lib/sympa/expl/`.


```
### Sympa transport
sympa_transport:
debug_print = "T: sympa_transport for
$local_part$local_part_suffix@$domain"
driver = pipe
command = SYMPA_QUEUE $local_part$local_part_suffix@$domain
current_directory = SYMPA_HOME
home_directory = SYMPA_HOME
user = SYMPA_UID
group = SYMPA_GID

sympaowner_transport:
debug_print = "T: sympaowner_transport for $local_part@$domain"
driver = pipe
command = SYMPA_BOUNCEQUEUE $local_part@$domain
current_directory = SYMPA_HOME
home_directory = SYMPA_HOME
user = SYMPA_UID
group = SYMPA_GID

sympabounce_transport:
driver = pipe
command = SYMPA_BOUNCEQUEUE sympa@$domain
current_directory = SYMPA_HOME
home_directory = SYMPA_HOME
user = SYMPA_UID
group = SYMPA_GID
```

Some more debug output (with unobfuscated data) in [1].


Kind regards,

Paul


[1]: https://paste.debian.net/1192347/