patch 8.0.1083: leaking memory in input part of channel

Problem:    Leaking memory in input part of channel.
Solution:   Clear the input part of channel.  Free the entry. Move failing
            command test to a separate file to avoid bogus leak reports
            clouding tests that should not leak.

src/Makefile

@@ -2265,6 +2265,7 @@ test_arglist \
 	test_taglist \
 	test_tcl \
 	test_terminal \
+	test_terminal_fail \
 	test_textobjects \
 	test_timers \
 	test_true_false \

src/channel.c

@@ -2939,6 +2939,7 @@ remove_from_writeque(writeq_T *wq, writeq_T *entry)
 	wq->wq_prev = NULL;
     else
 	wq->wq_next->wq_prev = NULL;
+    vim_free(entry);
 }
 
 /*
@@ -2990,7 +2991,7 @@ channel_clear(channel_T *channel)
     channel_clear_one(channel, PART_SOCK);
     channel_clear_one(channel, PART_OUT);
     channel_clear_one(channel, PART_ERR);
-    /* there is no callback or queue for PART_IN */
+    channel_clear_one(channel, PART_IN);
     free_callback(channel->ch_callback, channel->ch_partial);
     channel->ch_callback = NULL;
     channel->ch_partial = NULL;

src/testdir/Make_all.mak

@@ -194,6 +194,7 @@ NEW_TESTS = test_arabic.res \
 	    test_system.res \
 	    test_tcl.res \
 	    test_terminal.res \
+	    test_terminal_fail.res \
 	    test_textobjects.res \
 	    test_undo.res \
 	    test_usercommands.res \

src/testdir/test_terminal.vim

@@ -608,14 +608,6 @@ func Test_terminal_redir_file()
   endif
 
   if has('unix')
-    let buf = term_start('xyzabc', {'err_io': 'file', 'err_name': 'Xfile'})
-    call term_wait(buf)
-    call WaitFor('len(readfile("Xfile")) > 0')
-    call assert_match('executing job failed', readfile('Xfile')[0])
-    call WaitFor('!&modified')
-    call delete('Xfile')
-    bwipe
-
     call writefile(['one line'], 'Xfile')
     let buf = term_start('cat', {'in_io': 'file', 'in_name': 'Xfile'})
     call term_wait(buf)

src/testdir/test_terminal_fail.vim

@@ -0,0 +1,21 @@
+" This test is in a separate file, because it usually causes reports for memory
+" leaks under valgrind.  That is because when fork/exec fails memory is not
+" freed.  Since the process exists right away it's not a real leak.
+
+if !has('terminal')
+  finish
+endif
+
+source shared.vim
+
+func Test_terminal_redir_fails()
+  if has('unix')
+    let buf = term_start('xyzabc', {'err_io': 'file', 'err_name': 'Xfile'})
+    call term_wait(buf)
+    call WaitFor('len(readfile("Xfile")) > 0')
+    call assert_match('executing job failed', readfile('Xfile')[0])
+    call WaitFor('!&modified')
+    call delete('Xfile')
+    bwipe
+  endif
+endfunc

src/version.c

@@ -769,6 +769,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1083,
 /**/
     1082,
 /**/