add --ext-exit option

this is only a partial solution for reporting changes, but it's
adequate if the goal is merely triggering a bulk action, like
re-indexing the local store.

inspired by patches posted by Yuri D'Elia <wavexx@thregr.org>.

NEWS

@@ -27,6 +27,8 @@ Added support for mirroring deletions more accurately.
 
 Added --dry-run option.
 
+Added --ext-exit option.
+
 [1.4.0]
 
 The 'isync' compatibility wrapper was removed.

TODO

@@ -25,8 +25,6 @@ add alternative treatments of expired messages. ExpiredMessageMode: Prune
 separate folder - ArchiveSuffix, default .archive).
 
 add support for event notification callbacks.
-it would be also possible to report more differentiated exit codes, but
-that seems too limiting in the general case.
 
 make it possible to have different mailbox names for far and near side in
 Patterns.

src/common.h

@@ -115,6 +115,8 @@ BIT_ENUM(
 
 	DRYRUN,
 
+	EXT_EXIT,
+
 	ZERODELAY,
 	KEEPJOURNAL,
 	FORCEJOURNAL,

src/main.c

@@ -47,6 +47,7 @@ PACKAGE " " VERSION " - mailbox synchronizer\n"
 "  -c, --config CONFIG	read an alternate config file (default: ~/." EXE "rc)\n"
 "  -D, --debug		debugging modes (see manual)\n"
 "  -y, --dry-run		do not actually modify anything\n"
+"  -e, --ext-exit		return extended exit code\n"
 "  -V, --verbose		display what is happening\n"
 "  -q, --quiet		don't display progress counters\n"
 "  -v, --version		display version\n"
@@ -221,6 +222,8 @@ main( int argc, char **argv )
 					DFlags |= op;
 				} else if (!strcmp( opt, "dry-run" )) {
 					DFlags |= DRYRUN;
+				} else if (!strcmp( opt, "ext-exit" )) {
+					DFlags |= EXT_EXIT;
 				} else if (!strcmp( opt, "pull" )) {
 					cops |= XOP_PULL, mvars->ops[F] |= XOP_HAVE_TYPE;
 				} else if (!strcmp( opt, "push" )) {
@@ -461,6 +464,9 @@ main( int argc, char **argv )
 		case 'y':
 			DFlags |= DRYRUN;
 			break;
+		case 'e':
+			DFlags |= EXT_EXIT;
+			break;
 		case 'T':
 			for (; *ochar; ) {
 				switch (*ochar++) {

src/main_sync.c

@@ -388,6 +388,11 @@ sync_chans( core_vars_t *cvars, char **argv )
 	if (!cvars->list) {
 		flushn();
 		summary();
+		if (DFlags & EXT_EXIT) {
+			for (int t = 0; t < 2; t++)
+				if (new_done[t] || flags_done[t] || trash_done[t] || expunge_done[t])
+					cvars->ret |= 32 << t;
+		}
 	}
 }
 

src/mbsync.1

@@ -79,6 +79,12 @@ Enter simulation mode: the Channel status is queried and all required
 operations are determined, but no modifications are actually made
 to either the mailboxes or the state files.
 .TP
+\fB-e\fR, \fB--ext-exit\fR
+Return an extended exit code: Add 32 resp. 64 to the code if any
+modifications were made on the far resp. near side.
+An error may be reported at the same time, so the code may be for example
+65 if some changes were successfully pulled, while others failed.
+.TP
 \fB-V\fR, \fB--verbose\fR
 Enable \fIverbose\fR mode, which displays what is currently happening.
 .TP

src/sync.c

@@ -1776,7 +1776,7 @@ sync_close( sync_vars_t *svars, int t )
 
 	if ((svars->chan->ops[t] & (OP_EXPUNGE | OP_EXPUNGE_SOLO)) && !(DFlags & FAKEEXPUNGE)
 	    /*&& !(svars->state[t] & ST_TRASH_BAD)*/) {
-		if (Verbosity >= TERSE) {
+		if (Verbosity >= TERSE || (DFlags & EXT_EXIT)) {
 			if (svars->opts[t] & OPEN_UID_EXPUNGE) {
 				for (message_t *tmsg = svars->msgs[t]; tmsg; tmsg = tmsg->next) {
 					if (tmsg->status & M_DEAD)