py/repl: Filter private methods from tab completion.

Anything beginning with "_" will now only be tab-completed if there is
already a partial match for such an entry.  In other words, entering
foo.<tab> will no longer complete/list anything beginning with "_".

Originally at adafruit#1850

Signed-off-by: Kathryn Lingel <kathryn@lingel.net>

2 files changed, 10 insertions, 5 deletions

diff --git a/py/repl.c b/py/repl.c
index c758fc067b..3b1837031b 100644
--- a/py/repl.c
+++ b/py/repl.c
@@ -197,6 +197,11 @@ size_t mp_repl_autocomplete(const char *str, size_t len, const mp_print_t *print
             for (qstr q = MP_QSTR_ + 1; q < nqstr; ++q) {
                 size_t d_len;
                 const char *d_str = (const char *)qstr_data(q, &d_len);
+                // special case; filter out words that begin with underscore
+                // unless there's already a partial match
+                if (s_len == 0 && d_str[0] == '_') {
+                    continue;
+                }
                 if (s_len <= d_len && strncmp(s_start, d_str, s_len) == 0) {
                     mp_load_method_protected(obj, q, dest, true);
                     if (dest[0] != MP_OBJ_NULL) {
diff --git a/tests/unix/extra_coverage.py.exp b/tests/unix/extra_coverage.py.exp
index d97de2c0ef..ab4d977741 100644
--- a/tests/unix/extra_coverage.py.exp
+++ b/tests/unix/extra_coverage.py.exp
@@ -28,11 +28,11 @@ RuntimeError:
 # repl
 ame__
 
-__class__       __name__        argv            atexit
-byteorder       exc_info        exit            getsizeof
-implementation  maxsize         modules         path
-platform        print_exception                 stderr
-stdin           stdout          version         version_info
+argv            atexit          byteorder       exc_info
+exit            getsizeof       implementation  maxsize
+modules         path            platform        print_exception
+stderr          stdin           stdout          version
+version_info
 ementation
 # attrtuple
 (start=1, stop=2, step=3)