command: change "edition" property behavior

See manpage/changelog changes.

The purpose of this change is to removes another case of inconsistent
property behavior. At first I wanted to make this go through deprecation
before making a technically incompatible change, but then I considered
this feature too obscure as that anyone would care.

DOCS/interface-changes.rst

@@ -62,6 +62,11 @@ Interface changes
     - remove old Apple Remote support, including --input-appleremote
     - add MediaPlayer support and remove the old Media Key event tap on macOS.
       this possibly also re-adds the Apple Remote support
+    - the "edition" property now strictly returns the value of the option,
+      instead of the runtime value. The new "current-edition" property needs to
+      be queried to read the runtime-chosen edition. This is a breaking change
+      for any users which expected "edition" to return the runtime-chosen
+      edition at default settings (--edition=auto).
  --- mpv 0.30.0 ---
     - add `--d3d11-output-format` to enable explicit selection of a D3D11
       swap chain format.

DOCS/man/input.rst

@@ -1525,6 +1525,18 @@ Property list
     Current MKV edition number. Setting this property to a different value will
     restart playback. The number of the first edition is 0.
 
+    Before mpv 0.31.0, this showed the actual edition selected at runtime, if
+    you didn't set the option or property manually. With mpv 0.31.0 and later,
+    this strictly returns the user-set option or property value, and the
+    ``current-edition`` property was added to return the runtime selected
+    edition (this matters with ``--edition=auto``, the default).
+
+``current-edition``
+    Currently selected edition. This property is unavailable if no file is
+    loaded, or the file has no editions. (Matroska files make a difference
+    between having no editions and a single edition, which will be reflected by
+    the property, although in practice it does not matter.)
+
 ``chapters``
     Number of chapters.
 
@@ -2714,11 +2726,6 @@ caveats with some properties (due to historical reasons):
     *iff* video (for ``vf``) or audio (for ``af``) was active. If playback was
     not active, the behavior was the same as the current behavior.
 
-``edition``
-    While a file is loaded, the property will always return the effective
-    edition, and setting the ``auto`` value will show somewhat strange behavior
-    (the property eventually switching to whatever is the default edition).
-
 ``playlist``
     The property is read-only and returns the current internal playlist. The
     option is for loading playlist during command line parsing. For client API

player/command.c

@@ -1040,24 +1040,32 @@ static int mp_property_list_chapters(void *ctx, struct m_property *prop,
     return m_property_read_list(action, arg, count, get_chapter_entry, mpctx);
 }
 
+static int mp_property_current_edition(void *ctx, struct m_property *prop,
+                                      int action, void *arg)
+{
+    MPContext *mpctx = ctx;
+    struct demuxer *demuxer = mpctx->demuxer;
+    if (!demuxer || demuxer->num_editions <= 0)
+        return M_PROPERTY_UNAVAILABLE;
+    return m_property_int_ro(action, arg, demuxer->edition);
+}
+
 static int mp_property_edition(void *ctx, struct m_property *prop,
                                int action, void *arg)
 {
     MPContext *mpctx = ctx;
     struct demuxer *demuxer = mpctx->demuxer;
-    if (!mpctx->playback_initialized || !demuxer || demuxer->num_editions <= 0)
-        return mp_property_generic_option(mpctx, prop, action, arg);
 
-    switch (action) {
-    case M_PROPERTY_GET:
-        *(int *)arg = demuxer->edition;
+    if (action == M_PROPERTY_GET_CONSTRICTED_TYPE && demuxer) {
+        *(struct m_option *)arg = (struct m_option){
+            .type = CONF_TYPE_INT,
+            .flags = M_OPT_RANGE,
+            .min = 0,
+            .max = demuxer->num_editions - 1,
+        };
         return M_PROPERTY_OK;
-    case M_PROPERTY_GET_CONSTRICTED_TYPE: {
-        int r = mp_property_generic_option(mpctx, prop, M_PROPERTY_GET_TYPE, arg);
-        ((struct m_option *)arg)->max = demuxer->num_editions - 1;
-        return r;
-    }
     }
+
     return mp_property_generic_option(mpctx, prop, action, arg);
 }
 
@@ -3273,6 +3281,7 @@ static const struct m_property mp_properties_base[] = {
     {"playback-time", mp_property_playback_time},
     {"chapter", mp_property_chapter},
     {"edition", mp_property_edition},
+    {"current-edition", mp_property_current_edition},
     {"chapters", mp_property_chapters},
     {"editions", mp_property_editions},
     {"metadata", mp_property_metadata},