From 58e4d723383dfd9856520728b0920ff20fa76407 Mon Sep 17 00:00:00 2001
From: David Lechner <david@pybricks.com>
Date: Wed, 8 Apr 2020 12:17:28 -0500
Subject: [PATCH] py/objexcept: Pretty print OSError also when it has 2
 arguments.

This extends pretty-printing of OSError's to handle two arguments when the
exception name is known.

Signed-off-by: David Lechner <david@pybricks.com>
---
 py/objexcept.c             | 25 ++++++++++++++++---------
 tests/basics/errno1.py     |  4 ++++
 tests/basics/errno1.py.exp |  2 ++
 3 files changed, 22 insertions(+), 9 deletions(-)

diff --git a/py/objexcept.c b/py/objexcept.c
index f03bb1b416cf..a10bd2c18788 100644
--- a/py/objexcept.c
+++ b/py/objexcept.c
@@ -163,17 +163,24 @@ void mp_obj_exception_print(const mp_print_t *print, mp_obj_t o_in, mp_print_kin
         if (o->args == NULL || o->args->len == 0) {
             mp_print_str(print, "");
             return;
-        } else if (o->args->len == 1) {
-            #if MICROPY_PY_UERRNO
-            // try to provide a nice OSError error message
-            if (o->base.type == &mp_type_OSError && mp_obj_is_small_int(o->args->items[0])) {
-                qstr qst = mp_errno_to_str(o->args->items[0]);
-                if (qst != MP_QSTRnull) {
-                    mp_printf(print, "[Errno " INT_FMT "] %q", MP_OBJ_SMALL_INT_VALUE(o->args->items[0]), qst);
-                    return;
+        }
+
+        #if MICROPY_PY_UERRNO
+        // try to provide a nice OSError error message
+        if (o->base.type == &mp_type_OSError && o->args->len > 0 && o->args->len < 3 && mp_obj_is_small_int(o->args->items[0])) {
+            qstr qst = mp_errno_to_str(o->args->items[0]);
+            if (qst != MP_QSTRnull) {
+                mp_printf(print, "[Errno " INT_FMT "] %q", MP_OBJ_SMALL_INT_VALUE(o->args->items[0]), qst);
+                if (o->args->len > 1) {
+                    mp_print_str(print, ": ");
+                    mp_obj_print_helper(print, o->args->items[1], PRINT_STR);
                 }
+                return;
             }
-            #endif
+        }
+        #endif
+
+        if (o->args->len == 1) {
             mp_obj_print_helper(print, o->args->items[0], PRINT_STR);
             return;
         }
diff --git a/tests/basics/errno1.py b/tests/basics/errno1.py
index d7a5ccd542ac..d9a895a972d6 100644
--- a/tests/basics/errno1.py
+++ b/tests/basics/errno1.py
@@ -12,6 +12,10 @@
 # check that errors are rendered in a nice way
 msg = str(OSError(uerrno.EIO))
 print(msg[:7], msg[-5:])
+msg = str(OSError(uerrno.EIO, "details"))
+print(msg[:7], msg[-14:])
+msg = str(OSError(uerrno.EIO, "details", "more details"))
+print(msg[:1], msg[-28:])
 
 # check that unknown errno is still rendered
 print(str(OSError(9999)))
diff --git a/tests/basics/errno1.py.exp b/tests/basics/errno1.py.exp
index 7dd22757dddc..58605b4767a2 100644
--- a/tests/basics/errno1.py.exp
+++ b/tests/basics/errno1.py.exp
@@ -1,4 +1,6 @@
 <class 'int'>
 [Errno  ] EIO
+[Errno  ] EIO: details
+( , 'details', 'more details')
 9999
 uerrno