Add msmtp and msmtpq parsers

I created this script to help me test out this change:
<https://gist.github.com/Jayman2000/30fb19578ad2dd978b9420b9739ec915>

nixpkgs/test.nix

@@ -62,7 +62,7 @@
 
 let
  default_packages = [ bash file findutils gettext ];
- parsed_packages = [ coreutils sqlite unixtools.script gnused gawk findutils rlwrap gnutar bc ];
+ parsed_packages = [ coreutils sqlite unixtools.script gnused gawk findutils rlwrap gnutar bc msmtp ];
 in
 rec {
  module1 = resholve.mkDerivation {

resholve

@@ -2446,6 +2446,139 @@ class ExternalCommandParsers(object):
 
  return (generic,)
 
+ @staticmethod
+ def _msmtp():
+ """
+ This was based on running "msmtp --help" with msmtp v1.8.24.
+ """
+ generic = CommandParser("msmtp")
+
+ # General options
+ generic.add_argument(
+ "--version"
+ "--help",
+ "-P", "--pretend",
+ "-v", "-d", "--debug",
+ action="store_true"
+ )
+
+ # Changing the mode of operation
+ generic.add_argument("--configure", nargs=1)
+ generic.add_argument("-S", "--serverinfo", action="store_true")
+ generic.add_argument("--rmqs", nargs=1)
+
+ # Configuration options
+ generic.add_argument("-C", "--file", nargs=1)
+ # For msmtp, "-a" is nargs=1.
+ # For msmtpq, "--q-mgmt -a" is nargs=0.
+ generic.add_argument("-a", nargs="?")
+ generic.add_argument(
+ "--account",
+ "--host",
+ "--port",
+ nargs=1
+ )
+ generic.add_argument(
+ "--source-ip",
+ "--proxy-host",
+ "--proxy-port",
+ "--socket",
+ "--timeout",
+ "--protocol",
+ "--domain",
+ "--auth",
+ "--user",
+ nargs="?"
+ )
+ generic.add_argument(
+ "--passwordeval",
+ dest="commands",
+ action="invocations",
+ nargs=1
+ )
+ generic.add_argument(
+ "--tls",
+ "--tls-starttls",
+ "--tls-trust-file",
+ "--tls-crl-file",
+ "--tls-fingerprint",
+ "--tls-certcheck",
+ "--tls-key-file",
+ "--tls-cert-file",
+ "--tls-priorities",
+ "--tls-host-override",
+ "--tls-min-dh-prime-bits",
+ nargs="?"
+ )
+
+ # Options specific to sendmail mode
+ generic.add_argument(
+ "--auto-from",
+ "-f", "--from=address",
+ "--maildomain",
+ "-N", "--dsn-notify",
+ "-R", "--dsn-return",
+ "-X", "--logfile",
+ "--logfile-time-format",
+ "--syslog",
+ nargs="?"
+ )
+ generic.add_argument(
+ "-t", "--read-recipients",
+ "--read-envelope-from",
+ action="store_true"
+ )
+ generic.add_argument(
+ "--aliases",
+ "--set-from-header",
+ "--set-date-header",
+ "--set-msgid-header",
+ "--remove-bcc-headers",
+ "--undisclosed-recipients",
+ nargs="?"
+ )
+ # Accepted but ignored:
+ generic.add_argument("-A", action="store_true")
+ generic.add_argument("-B", nargs=1)
+ generic.add_argument("-bm", action="store_true")
+ generic.add_argument("-F", nargs=1)
+ generic.add_argument("-G", action="store_true")
+ # For msmtp, "-h" is nargs=1.
+ # For msmtpq "--q-mgmt -h" is nargs=0.
+ generic.add_argument("-h", nargs="?")
+ generic.add_argument("-i", action="store_true")
+ generic.add_argument("-L", nargs=1)
+ generic.add_argument(
+ "-m",
+ "-n",
+ action="store_true"
+ )
+ generic.add_argument(
+ "-O",
+ # See <https://github.com/abathur/resholve/pull/103#issuecomment-1710979420>
+ action="count"
+ )
+ generic.add_argument("-o", nargs=1)
+
+ return (generic,)
+
+ @classmethod
+ def _msmtpq(cls):
+ """
+ This was based on running "msmtpq --q-mgmt -h" with msmtp v1.8.24.
+ """
+ generic = cls._msmtp()[0]
+
+ # -R, -d, -a and -h are already handled by the msmtp parser.
+ generic.add_argument(
+ "--q-mgmt",
+ "-r",
+ "-p",
+ action="store_true"
+ )
+
+ return (generic,)
+
 
 def generate_builtin_command_parser(cmdname):
  cmdname = "_" + cmdname

tests/parse_msmtp.sh

@@ -0,0 +1,25 @@
+temp_dir="$(mktemp -d --suffix=resholve-tests-parse-msmtp)"
+trap 'rm -rf -- "$temp_dir"' EXIT
+config="$temp_dir/msmtprc"
+email="$temp_dir/test.eml"
+export MSMTPQ_LOG="$temp_dir/msmtpq_log"
+export MSMTPQ_Q="$temp_dir/msmtpq_q"
+# TODO: We can remove this next line once this Nixpkgs PR gets merged:
+# <https://github.com/NixOS/nixpkgs/pull/296720>
+export MSMTP_LOG="$MSMTPQ_LOG" MSMTP_QUEUE="$MSMTPQ_Q"
+
+echo '
+ account default
+ host example.com
+' > "$config"
+echo -ne 'To: foo@example.org\r\n' > "$email"
+echo -ne 'MIME-Version: 1.0\r\n' >> "$email"
+echo -ne '\r\n' >> "$email"
+
+< "$email" msmtp -PC "$config" --passwordeval=cat
+< "$email" msmtp -PC "$config" --passwordeval cat
+< "$email" msmtpq -PC "$config" --passwordeval=cat
+< "$email" msmtpq -PC "$config" --passwordeval cat
+# TODO: These commands are valid, but our parse doesn’t support them yet.
+#< "$email" msmtp -PC "$config" --passwordeval=
+#< "$email" msmtpq -PC "$config" --passwordeval=