Transport: permit an empty string for the transport_filter option. Bug 1714

10 files changed, 87 insertions, 24 deletions

diff --git a/doc/doc-docbook/spec.xfpt b/doc/doc-docbook/spec.xfpt
index b0b1585fe..af57d9b85 100644
--- a/doc/doc-docbook/spec.xfpt
+++ b/doc/doc-docbook/spec.xfpt
@@ -20717,6 +20717,9 @@ headers that some sites insist on.
 This option sets up a filtering (in the Unix shell sense) process for messages
 at transport time. It should not be confused with mail filtering as set up by
 individual users or via a system filter.
+.new
+If unset, or expanding to an empty string, no filtering is done.
+.wen
 
 When the message is about to be written out, the command specified by
 &%transport_filter%& is started up in a separate, parallel process, and
diff --git a/doc/doc-txt/ChangeLog b/doc/doc-txt/ChangeLog
index 4e5663fab..2caae227c 100644
--- a/doc/doc-txt/ChangeLog
+++ b/doc/doc-txt/ChangeLog
@@ -73,6 +73,9 @@ JH/14 Change header file name for freeradius-client.  Relevant if compiling
 
 JH/15 Bug 1712: Introduce $prdr_requested flag variable
 
+JH/16 Bug 1714: Permit an empty string as expansion result for transport
+      option transport_filter, meaning no filtering.
+
 
 Exim version 4.86
 -----------------
diff --git a/src/src/transport.c b/src/src/transport.c
index 62cbdc632..e77479b97 100644
--- a/src/src/transport.c
+++ b/src/src/transport.c
@@ -1213,7 +1213,10 @@ transport_filter_timed_out = FALSE;
 /* If there is no filter command set up, call the internal function that does
 the actual work, passing it the incoming fd, and return its result. */
 
-if (transport_filter_argv == NULL)
+if (  !transport_filter_argv
+   || !*transport_filter_argv
+   || !**transport_filter_argv
+   )
   return internal_transport_write_message(addr, fd, options, size_limit,
     add_headers, remove_headers, check_string, escape_string,
     rewrite_rules, rewrite_existflags);
diff --git a/test/log/0393 b/test/log/0393
index dee87e361..7d70439a0 100644
--- a/test/log/0393
+++ b/test/log/0393
@@ -1,5 +1,9 @@
+1999-03-02 09:44:33 10HmaX-0005vi-00 <= CALLER@test.ex U=CALLER P=local S=sss
+1999-03-02 09:44:33 10HmaX-0005vi-00 => userx <userx@test.ex> R=r1 T=t1
+1999-03-02 09:44:33 10HmaX-0005vi-00 Completed
 1999-03-02 09:44:33 10HmaY-0005vi-00 <= CALLER@test.ex U=CALLER P=local S=sss
 1999-03-02 09:44:33 10HmaY-0005vi-00 => userx <userx@test.ex> R=r1 T=t1
 1999-03-02 09:44:33 10HmaY-0005vi-00 Completed
-1999-03-02 09:44:33 10HmaX-0005vi-00 <= CALLER@test.ex U=CALLER P=local S=sss
-1999-03-02 09:44:33 10HmaX-0005vi-00 == userx@test.ex R=r1 T=t1 defer (-24): transport filter process failed (127) while writing to TESTSUITE/test-mail/userx: unable to execute command
+1999-03-02 09:44:33 10HmaZ-0005vi-00 <= CALLER@test.ex U=CALLER P=local S=sss
+1999-03-02 09:44:33 10HmaZ-0005vi-00 => userx <userx@test.ex> R=r1 T=t1
+1999-03-02 09:44:33 10HmaZ-0005vi-00 Completed
diff --git a/test/mail/0393.userx b/test/mail/0393.userx
index ab724c4ef..24ab3d64f 100644
--- a/test/mail/0393.userx
+++ b/test/mail/0393.userx
@@ -1,11 +1,33 @@
 From CALLER@test.ex Tue Mar 02 09:44:33 1999
 Received: from CALLER by the.local.host.name with local (Exim x.yz)
 	(envelope-from <CALLER@test.ex>)
+	id 10HmaX-0005vi-00
+	for userx@test.ex; Tue, 2 Mar 1999 09:44:33 +0000
+Message-Id: <E10HmaX-0005vi-00@the.local.host.name>
+From: CALLER_NAME <CALLER@test.ex>
+Date: Tue, 2 Mar 1999 09:44:33 +0000
+
+Testing with filter
+
+From CALLER@test.ex Tue Mar 02 09:44:33 1999
+Received: from CALLER by the.local.host.name with local (Exim x.yz)
+	(envelope-from <CALLER@test.ex>)
 	id 10HmaY-0005vi-00
 	for userx@test.ex; Tue, 2 Mar 1999 09:44:33 +0000
 Message-Id: <E10HmaY-0005vi-00@the.local.host.name>
 From: CALLER_NAME <CALLER@test.ex>
 Date: Tue, 2 Mar 1999 09:44:33 +0000
 
-Testing with filter
+Testing without filter
+
+From CALLER@test.ex Tue Mar 02 09:44:33 1999
+Received: from CALLER by the.local.host.name with local (Exim x.yz)
+	(envelope-from <CALLER@test.ex>)
+	id 10HmaZ-0005vi-00
+	for userx@test.ex; Tue, 2 Mar 1999 09:44:33 +0000
+Message-Id: <E10HmaZ-0005vi-00@the.local.host.name>
+From: CALLER_NAME <CALLER@test.ex>
+Date: Tue, 2 Mar 1999 09:44:33 +0000
+
+Testing with expand-to-empty filter
 
diff --git a/test/msglog/0393.10HmaX-0005vi-00 b/test/msglog/0393.10HmaX-0005vi-00
deleted file mode 100644
index 4586818bc..000000000
--- a/test/msglog/0393.10HmaX-0005vi-00
+++ /dev/null
@@ -1,2 +0,0 @@
-1999-03-02 09:44:33 Received from CALLER@test.ex U=CALLER P=local S=sss
-1999-03-02 09:44:33 userx@test.ex R=r1 T=t1 defer (-24): transport filter process failed (127) while writing to TESTSUITE/test-mail/userx: unable to execute command
diff --git a/test/paniclog/0393 b/test/paniclog/0393
deleted file mode 100644
index 0fee43b5a..000000000
--- a/test/paniclog/0393
+++ /dev/null
@@ -1 +0,0 @@
-1999-03-02 09:44:33 10HmaX-0005vi-00 == userx@test.ex R=r1 T=t1 defer (-24): transport filter process failed (127) while writing to TESTSUITE/test-mail/userx: unable to execute command
diff --git a/test/runtest b/test/runtest
index 7e2dbe8eb..6899caeff 100755
--- a/test/runtest
+++ b/test/runtest
@@ -1362,9 +1362,6 @@ $munges =
     'optional_ocsp' =>
     { 'stderr' => '/127.0.0.1 in hosts_requ(ire|est)_ocsp/' },
 
-    'no_tpt_filter_epipe' =>
-    { 'stderr' => '/^writing error 32: Broken pipe$/' },
-
     'optional_cert_hostnames' =>
     { 'stderr' => '/in tls_verify_cert_hostnames\? no/' },
 
diff --git a/test/scripts/0000-Basic/0393 b/test/scripts/0000-Basic/0393
index f34154c93..dfd549a05 100644
--- a/test/scripts/0000-Basic/0393
+++ b/test/scripts/0000-Basic/0393
@@ -1,10 +1,11 @@
 # empty transport filter
 #
-munge no_tpt_filter_epipe
-#
 exim -d-all+transport -odi userx
 Testing with filter
 ****
 exim -DFILTER= -d-all+transport -odi userx
 Testing without filter
 ****
+exim -DFILTER='${if={1}{1}{}{}}'  -d-all+transport -odi userx
+Testing with expand-to-empty filter
+****
diff --git a/test/stderr/0393 b/test/stderr/0393
index a7d72dc98..c40aa6f52 100644
--- a/test/stderr/0393
+++ b/test/stderr/0393
@@ -70,18 +70,51 @@ lock file created
 mailbox TESTSUITE/test-mail/userx is locked
 writing to file TESTSUITE/test-mail/userx
 writing data block fd=dddd size=sss timeout=0
-process pppp running as transport filter: write=dddd read=dddd
 writing data block fd=dddd size=sss timeout=0
-process pppp writing to transport filter
-copying from the filter
-waiting for filter process
-filter process returned 127
-waiting for writing process
-end of filtering transport writing: yield=0
-errno=-24 more_errno=dd
-appendfile yields 10 with errno=-24 more_errno=dd
-t1 transport returned PANIC for userx@test.ex
-LOG: MAIN PANIC
-  == userx@test.ex R=r1 T=t1 defer (-24): transport filter process failed (127) while writing to TESTSUITE/test-mail/userx: unable to execute command
+writing data block fd=dddd size=sss timeout=0
+appendfile yields 0 with errno=dd more_errno=dd
+t1 transport returned OK for userx@test.ex
+LOG: MAIN
+  => userx <userx@test.ex> R=r1 T=t1
+LOG: MAIN
+  Completed
+>>>>>>>>>>>>>>>> Exim pid=pppp terminating with rc=0 >>>>>>>>>>>>>>>>
+>>>>>>>>>>>>>>>> Exim pid=pppp terminating with rc=0 >>>>>>>>>>>>>>>>
+Exim version x.yz ....
+configuration file is TESTSUITE/test-config
+admin user
+LOG: MAIN
+  <= CALLER@test.ex U=CALLER P=local S=sss
+Exim version x.yz ....
+configuration file is TESTSUITE/test-config
+trusted user
+admin user
+>>>>>>>>>>>>>>>> Local deliveries >>>>>>>>>>>>>>>>
+--------> userx@test.ex <--------
+direct command:
+  argv[0] = ${if={1}{1}{}{}}
+direct command after expansion:
+  argv[0] = 
+appendfile transport entered
+appendfile: mode=600 notify_comsat=0 quota=0 warning=0
+  file=TESTSUITE/test-mail/userx format=unix
+  message_prefix=From ${if def:return_path{$return_path}{MAILER-DAEMON}} ${tod_bsdinbox}\n
+  message_suffix=\n
+  maildir_use_size_file=no
+  locking by lockfile fcntl 
+lock name: TESTSUITE/test-mail/userx.lock
+hitch name: TESTSUITE/test-mail/userx.lock.test.ex.dddddddd.pppppppp
+lock file created
+mailbox TESTSUITE/test-mail/userx is locked
+writing to file TESTSUITE/test-mail/userx
+writing data block fd=dddd size=sss timeout=0
+writing data block fd=dddd size=sss timeout=0
+writing data block fd=dddd size=sss timeout=0
+appendfile yields 0 with errno=dd more_errno=dd
+t1 transport returned OK for userx@test.ex
+LOG: MAIN
+  => userx <userx@test.ex> R=r1 T=t1
+LOG: MAIN
+  Completed
 >>>>>>>>>>>>>>>> Exim pid=pppp terminating with rc=0 >>>>>>>>>>>>>>>>
 >>>>>>>>>>>>>>>> Exim pid=pppp terminating with rc=0 >>>>>>>>>>>>>>>>