email: allow null certificatesFile

Allow the value of certificatesFile to be null.

Also fixup uses of this variable.

Fixes: #2206

modules/accounts/email.nix

@@ -71,7 +71,7 @@ let
       };
 
       certificatesFile = mkOption {
-        type = types.path;
+        type = types.nullOr types.path;
         default = config.accounts.email.certificatesFile;
         defaultText = "config.accounts.email.certificatesFile";
         description = ''
@@ -354,7 +354,7 @@ let
 in {
   options.accounts.email = {
     certificatesFile = mkOption {
-      type = types.path;
+      type = types.nullOr types.path;
       default = "/etc/ssl/certs/ca-certificates.crt";
       description = ''
         Path to default file containing certificate authorities that

modules/programs/git.nix

@@ -295,7 +295,8 @@ in {
                   "ssl")
               else
                 "";
-              smtpSslCertPath = mkIf smtp.tls.enable smtp.tls.certificatesFile;
+              smtpSslCertPath =
+                mkIf smtp.tls.enable (toString smtp.tls.certificatesFile);
               smtpServer = smtp.host;
               smtpUser = userName;
               from = address;

modules/programs/msmtp.nix

@@ -21,11 +21,12 @@ let
         user = userName;
         tls = onOff smtp.tls.enable;
         tls_starttls = onOff smtp.tls.useStartTls;
-        tls_trust_file = smtp.tls.certificatesFile;
       } // optionalAttrs (msmtp.tls.fingerprint != null) {
         tls_fingerprint = msmtp.tls.fingerprint;
       } // optionalAttrs (smtp.port != null) { port = toString smtp.port; }
-        // optionalAttrs (passwordCommand != null) {
+        // optionalAttrs (smtp.tls.certificatesFile != null) {
+          tls_trust_file = smtp.tls.certificatesFile;
+        } // optionalAttrs (passwordCommand != null) {
           passwordeval = toString passwordCommand;
         } // msmtp.extraConfig) ++ optional primary ''
 

modules/programs/neomutt.nix

@@ -185,7 +185,7 @@ let
     ''
       # Generated by Home Manager.
       set ssl_force_tls = yes
-      set certificate_file=${config.accounts.email.certificatesFile}
+      set certificate_file=${toString config.accounts.email.certificatesFile}
 
       # GPG section
       set crypt_use_gpgme = yes

modules/programs/offlineimap.nix

@@ -56,7 +56,7 @@ let
 
       ssl = if imap.tls.enable then {
         ssl = true;
-        sslcacertfile = imap.tls.certificatesFile;
+        sslcacertfile = toString imap.tls.certificatesFile;
         starttls = imap.tls.useStartTls;
       } else {
         ssl = false;