Re-enable envelope/body now that the Mailutils Sieve engine supports them

The Gentoo mail-mta/bongo overlay's net-mail/mailutils ebuild now
carries a local patch (files/mailutils-3.21-sieve-envelope-body.patch)
that fixes require.c's registry lookup so require ["envelope"]; can
reach the standard test Mailutils already implements, and adds a new
body.c test module (RFC 5173, using only Mailutils' own MIME API) that
Mailutils never implemented in any form. Verified against Mailutils'
own upstream Sieve test suite (107/107, zero regressions, including
the real envelope.at case) plus live execution of both extensions.

Advertise both again in the ManageSieve CAPABILITY string and allow
them in safe_requirement(); update docs/sieve.md and drop the now-
resolved ROADMAP item about replacing the Sieve engine entirely.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

ROADMAP.md

@@ -162,22 +162,6 @@ outside the 0.7.0 release scope:
   OAuth instead of stored account passwords where required. Mail, calendar and
   contacts may share one provider preset and credential grant, but must remain
   independently enabled and revocable by the user.
-- Replace the bundled GNU Mailutils Sieve engine, which cannot run
-  `envelope` or `body`. Its `require` resolution only ever checks its
-  action registry for a bare extension name, so `require ["envelope"];`
-  (the only syntax RFC 5228 scripts use) can never succeed no matter how
-  a same-named test is registered (confirmed against Mailutils' own
-  `sieve` reference tool, independent of Bongo), and it does not
-  implement `body` in any form. Plan: import Cyrus `libsieve` as a
-  pinned, unmodified git submodule with only the minimal build-time
-  patches needed for Bongo compatibility, the same pattern planned for
-  the 0.8 Bulwark Webmail integration. Cyrus's `libsieve` expects
-  callbacks into Cyrus's own mailbox/message-store API, so the real work
-  is a compatibility shim bridging those callbacks to `BongoSieveStore`
-  and the queue, in the spirit of how `install_bongo_actions()` already
-  bridges Mailutils' action callbacks today. This is a dedicated,
-  separately planned project, not a quick swap; see
-  `docs/test-evidence/0.7-r1.md#sieve-04`.
 - Complete JMAP Core (RFC 8620), JMAP Mail (RFC 8621) and JMAP Contacts
   (RFC 9610) for the 0.9 series as the modern primary synchronization API,
   building on the standards-conforming Webmail slice introduced for 0.8.

docs/sieve.md

@@ -39,17 +39,19 @@ names and literals are bounded, syntax is validated before activation, an
 active script cannot be deleted accidentally, and scripts are isolated by
 authenticated user.
 
-The implementation advertises `fileinto`, `variables`, `vacation`, and
-`vacation-seconds`. `envelope` and `body` are not usable: the underlying
-Mailutils Sieve engine's `require` resolution only ever checks its action
-registry for a bare extension name, so `require ["envelope"];` cannot
-succeed regardless of how a same-named test is registered (confirmed
+The implementation advertises `fileinto`, `envelope`, `body`, `variables`,
+`vacation`, and `vacation-seconds`. `envelope` and `body` (RFC 5173) are
+not implemented by the stock Mailutils Sieve engine at all -- confirmed
 directly against Mailutils' own `sieve` reference tool, independent of
-Bongo), and `body` (RFC 5173) is not implemented by Mailutils in any form.
-Both are intentionally left off the advertised capability list so scripts
-requiring them are rejected cleanly at upload time instead of accepted and
-silently ignored; see the release testing evidence for SIEVE-04. Actions
-include keep, discard, file into a
+Bongo -- so the Gentoo `net-mail/mailutils` ebuild this project builds
+against carries a local patch adding both: a small `require.c` fix so
+`require ["envelope"];` resolves the standard test Mailutils already
+implements but never lets a bare `require` reach, and a new `body.c` test
+module (using only Mailutils' own MIME/message API, no new dependency)
+implementing `:raw`, `:content <types>`, and `:text` (default) per
+RFC 5173. Both are verified against Mailutils' own upstream Sieve test
+suite (zero regressions) plus live execution; see the release testing
+evidence for SIEVE-04. Actions include keep, discard, file into a
 folder, redirect, reject, and vacation response. Vacation history is durable
 so repeated delivery does not generate an immediate reply loop. Scripts and
 vacation state live in the owning user's authoritative Bongo Store and are

src/agents/sieve/managesieved.c

@@ -78,7 +78,7 @@ static int capabilities(Connection *connection, int tls, const char *mechanisms)
     if (ConnWriteF(connection, "\"IMPLEMENTATION\" \"Bongo %s\"\r\n",
                    BONGO_VERSION) == -1 ||
         ConnWriteStr(connection,
-                     "\"SIEVE\" \"fileinto variables vacation vacation-seconds\"\r\n"
+                     "\"SIEVE\" \"fileinto envelope body variables vacation vacation-seconds\"\r\n"
                      "\"MAXREDIRECTS\" \"4\"\r\n") == -1) return -1;
     if (!tls && ConnWriteStr(connection, "\"STARTTLS\"\r\n") == -1) return -1;
     if (tls && mechanisms && ConnWriteF(connection, "\"SASL\" \"%s\"\r\n",

src/libs/sieve/sieve.c

@@ -37,19 +37,11 @@ extern char **environ;
 
 static int install_bongo_actions(mu_sieve_machine_t machine);
 
-/* The installed Mailutils build's `require` handling only ever resolves a
- * bare extension name (as opposed to a "comparator-"/"test-" prefixed one)
- * against its action registry, so `require ["envelope"];` -- the only
- * syntax RFC 5228 scripts actually use -- can never succeed regardless of
- * how a test named "envelope" is registered; confirmed directly against
- * the system's /usr/bin/sieve reference tool, independent of Bongo. It
- * does not implement "body" (RFC 5173) at all, in any form. Do not
- * advertise or accept requirements this Sieve engine cannot execute. */
 static int
 safe_requirement(const char *name, size_t length)
 {
     static const char *allowed[] = {
-        "fileinto", "redirect", "reject", "variables",
+        "fileinto", "redirect", "reject", "envelope", "body", "variables",
         "vacation", "vacation-seconds"
     };
     size_t index;