[glib: 3/5] Mark g_subprocess_get_std{in, out, err}_pipe() return value as nullable

[Philip Withnall <pwithnall src gnome org>]

commit ec9fb90b2b978f2bb6eb44714fb43dc45ef2b81c
Author: Sebastian Dröge <sebastian centricular com>
Date:   Tue Nov 10 19:50:51 2020 +0200

    Mark g_subprocess_get_std{in,out,err}_pipe() return value as nullable
    
    Previously it was considered a programming error to call these on
    subprocesses created without the correct flags, but for bindings this
    distinction is difficult to handle automatically.
    
    Returning NULL instead does not cause any inconsistent behaviour and
    simplifies the API.

 gio/gsubprocess.c | 21 +++++++++------------
 1 file changed, 9 insertions(+), 12 deletions(-)
---
diff --git a/gio/gsubprocess.c b/gio/gsubprocess.c
index 8cc935423..4bf1f6b88 100644
--- a/gio/gsubprocess.c
+++ b/gio/gsubprocess.c
@@ -773,10 +773,10 @@ g_subprocess_get_identifier (GSubprocess *subprocess)
  * Gets the #GOutputStream that you can write to in order to give data
  * to the stdin of @subprocess.
  *
- * The process must have been created with
- * %G_SUBPROCESS_FLAGS_STDIN_PIPE.
+ * The process must have been created with %G_SUBPROCESS_FLAGS_STDIN_PIPE and
+ * not %G_SUBPROCESS_FLAGS_STDIN_INHERIT, otherwise %NULL will be returned.
  *
- * Returns: (transfer none): the stdout pipe
+ * Returns: (nullable) (transfer none): the stdout pipe
  *
  * Since: 2.40
  **/
@@ -784,7 +784,6 @@ GOutputStream *
 g_subprocess_get_stdin_pipe (GSubprocess *subprocess)
 {
   g_return_val_if_fail (G_IS_SUBPROCESS (subprocess), NULL);
-  g_return_val_if_fail (subprocess->stdin_pipe, NULL);
 
   return subprocess->stdin_pipe;
 }
@@ -796,10 +795,10 @@ g_subprocess_get_stdin_pipe (GSubprocess *subprocess)
  * Gets the #GInputStream from which to read the stdout output of
  * @subprocess.
  *
- * The process must have been created with
- * %G_SUBPROCESS_FLAGS_STDOUT_PIPE.
+ * The process must have been created with %G_SUBPROCESS_FLAGS_STDOUT_PIPE,
+ * otherwise %NULL will be returned.
  *
- * Returns: (transfer none): the stdout pipe
+ * Returns: (nullable) (transfer none): the stdout pipe
  *
  * Since: 2.40
  **/
@@ -807,7 +806,6 @@ GInputStream *
 g_subprocess_get_stdout_pipe (GSubprocess *subprocess)
 {
   g_return_val_if_fail (G_IS_SUBPROCESS (subprocess), NULL);
-  g_return_val_if_fail (subprocess->stdout_pipe, NULL);
 
   return subprocess->stdout_pipe;
 }
@@ -819,10 +817,10 @@ g_subprocess_get_stdout_pipe (GSubprocess *subprocess)
  * Gets the #GInputStream from which to read the stderr output of
  * @subprocess.
  *
- * The process must have been created with
- * %G_SUBPROCESS_FLAGS_STDERR_PIPE.
+ * The process must have been created with %G_SUBPROCESS_FLAGS_STDERR_PIPE,
+ * otherwise %NULL will be returned.
  *
- * Returns: (transfer none): the stderr pipe
+ * Returns: (nullable) (transfer none): the stderr pipe
  *
  * Since: 2.40
  **/
@@ -830,7 +828,6 @@ GInputStream *
 g_subprocess_get_stderr_pipe (GSubprocess *subprocess)
 {
   g_return_val_if_fail (G_IS_SUBPROCESS (subprocess), NULL);
-  g_return_val_if_fail (subprocess->stderr_pipe, NULL);
 
   return subprocess->stderr_pipe;
 }