[PATCHv15 2/5] run_processes_parallel: add LF when caller is sloppy

@@ -897,6 +897,7 @@ struct parallel_processes {
 	struct pollfd *pfd;
 
 	unsigned shutdown : 1;
+	unsigned ended_with_newline: 1;
 
 	int output_owner;
 	struct strbuf buffered_output; /* of finished children */

@@ -979,6 +980,7 @@ static void pp_init(struct parallel_processes *pp,
 	pp->nr_processes = 0;
 	pp->output_owner = 0;
 	pp->shutdown = 0;
+	pp->ended_with_newline = 1;
 	pp->children = xcalloc(n, sizeof(*pp->children));
 	pp->pfd = xcalloc(n, sizeof(*pp->pfd));
 	strbuf_init(&pp->buffered_output, 0);

@@ -1053,6 +1055,7 @@ static int pp_start_one(struct parallel_processes *pp)
 					 pp->data,
 					 &pp->children[i].data);
 		strbuf_addbuf(&pp->buffered_output, &pp->children[i].err);
+		strbuf_addch(&pp->buffered_output, '\n');
 		strbuf_reset(&pp->children[i].err);
 		if (code)
 			pp->shutdown = 1;

@@ -1095,9 +1098,11 @@ static void pp_buffer_stderr(struct parallel_processes *pp, int output_timeout)
 static void pp_output(struct parallel_processes *pp)
 {
 	int i = pp->output_owner;
-	if (pp->children[i].state == GIT_CP_WORKING &&
-	    pp->children[i].err.len) {
+	size_t len = pp->children[i].err.len;
+	if (pp->children[i].state == GIT_CP_WORKING && len) {
 		fputs(pp->children[i].err.buf, stderr);
+		pp->ended_with_newline =
+			(pp->children[i].err.buf[len - 1] == '\n');
 		strbuf_reset(&pp->children[i].err);
 	}
 }

@@ -1107,6 +1112,7 @@ static int pp_collect_finished(struct parallel_processes *pp)
 	int i, code;
 	int n = pp->max_processes;
 	int result = 0;
+	ssize_t len;
 
 	while (pp->nr_processes > 0) {
 		for (i = 0; i < pp->max_processes; i++)

@@ -1131,12 +1137,19 @@ static int pp_collect_finished(struct parallel_processes *pp)
 		pp->pfd[i].fd = -1;
 		child_process_init(&pp->children[i].process);
 
+		len = pp->children[i].err.len - 1;
+		if (len >= 0 && pp->children[i].err.buf[len] != '\n')
+			strbuf_addch(&pp->children[i].err, '\n');
+
 		if (i != pp->output_owner) {
 			strbuf_addbuf(&pp->buffered_output, &pp->children[i].err);
 			strbuf_reset(&pp->children[i].err);
 		} else {
+			if (len == -1 && !pp->ended_with_newline)
+				strbuf_addch(&pp->children[i].err, '\n');
 			fputs(pp->children[i].err.buf, stderr);
 			strbuf_reset(&pp->children[i].err);
+			pp->ended_with_newline = 1;
 
 			/* Output all other finished child processes */
 			fputs(pp->buffered_output.buf, stderr);

@@ -77,6 +77,32 @@ test_expect_success 'run_command runs in parallel with more tasks than jobs avai
 	test_cmp expect actual
 '
 
+test_expect_success 'run_command ensures each command ends in LF' '
+	test-run-command run-command-parallel 3 sh -c "printf \"%s\n%s\" Hello World" 2>actual &&
+	test_cmp expect actual
+'
+
+cat >expect <<-EOF
+preloaded output of a child
+preloaded output of a child
+preloaded output of a child
+preloaded output of a child
+EOF
+
+test_expect_success 'run_command ensures each command ends in LF when output is only in starting cb' '
+	test-run-command run-command-parallel 3 sh -c true  2>actual &&
+	test_cmp expect actual
+'
+
+cat >expect <<-EOF
+EOF
+
+test_expect_success 'run_command ensures each command ends in LF except when there is no output' '
+	test-run-command run-command-parallel-silent 3 sh -c true  2>actual &&
+	test_cmp expect actual
+'
+
+
 cat >expect <<-EOF
 preloaded output of a child
 asking for a quick stop

@@ -31,6 +31,20 @@ static int parallel_next(struct child_process *cp,
 	return 1;
 }
 
+static int parallel_next_silent(struct child_process *cp,
+			 struct strbuf *err,
+			 void *cb,
+			 void **task_cb)
+{
+	struct child_process *d = cb;
+	if (number_callbacks >= 4)
+		return 0;
+
+	argv_array_pushv(&cp->args, d->argv);
+	number_callbacks++;
+	return 1;
+}
+
 static int no_job(struct child_process *cp,
 		  struct strbuf *err,
 		  void *cb,

@@ -71,6 +85,10 @@ int main(int argc, char **argv)
 	jobs = atoi(argv[2]);
 	proc.argv = (const char **)argv + 3;
 
+	if (!strcmp(argv[1], "run-command-parallel-silent"))
+		exit(run_processes_parallel(jobs, parallel_next_silent,
+					    NULL, NULL, &proc));
+
 	if (!strcmp(argv[1], "run-command-parallel"))
 		exit(run_processes_parallel(jobs, parallel_next,
 					    NULL, NULL, &proc));