Many, many bug fixes, made work with mouse past RETRO_SHIFT, IGNORE_M…

…OD_TAP_INTERRUPT changes.

Fixed rolling from one AS key to another and holding the second sending both unshifted
Stopped tapping an AS key, tapping a non-AS key, and holding the same AS key from keyrepeating
Using CTRL_T(KC_A) as a mod on KC_A and releasing CTRL_T should no longer also release KC_A
Fixed IGNORE_MOD_TAP_INTERRUPT leaving the modifier pressed in some cases
Fixed keyrepeating mod tap then tapping another sending the mod tap key

docs/tap_hold.md

@@ -218,6 +218,12 @@ If `RETRO_SHIFT` is defined to a value, hold times greater than that value will
 #define RETRO_SHIFT 500
 ```
 
+This value (if set) must be greater than one's `TAPPING_TERM`, as the key press must be designated as a 'hold' by the time we send the modifier for use with mouse or return true on its release if `RETRO_SHIFT` is exceeded. There is no such limitation in regards to `AUTO_SHIFT_TIMEOUT`.
+
+### Retro Shift and IGNORE_MOD_TAP_INTERRUPT
+
+`IGNORE_MOD_TAP_INTERRUPT` works a little differently when using Retro Shift. Referencing the `TAPPING_TERM` makes little sense, as holding longer will result in shifting one of the keys. Instead, it simply makes rolling from a mod tap (releasing it first) send both keys instead of the modifier on the second.
+
 ## Why do we include the key record for the per key functions? 
 
 One thing that you may notice is that we include the key record for all of the "per key" functions, and may be wondering why we do that.

quantum/process_keycode/process_auto_shift.c

@@ -111,19 +111,10 @@ static bool autoshift_press(uint16_t keycode, uint16_t now, keyrecord_t *record)
  */
 static void autoshift_end(uint16_t keycode, uint16_t now, bool matrix_trigger) {
     // Called on key down with KC_NO, auto-shifted key up, and timeout.
-    if (autoshift_flags.in_progress) {
+    if (autoshift_flags.in_progress && (keycode == autoshift_lastkey || keycode == KC_NO)) {
         // Process the auto-shiftable key.
         autoshift_flags.in_progress = false;
 
-#    ifdef RETRO_SHIFT
-        if (retroshift_lastkey != KC_NO) {
-            if ((RETRO_SHIFT + 0) != 0 && TIMER_DIFF_16(now, retroshift_time) > (RETRO_SHIFT + 0)) {
-                return;
-            }
-            autoshift_time = retroshift_time;
-            autoshift_lastkey = retroshift_lastkey;
-        }
-#    endif
         // Time since the initial press was recorded.
         const uint16_t elapsed = TIMER_DIFF_16(now, autoshift_time);
         if (elapsed < autoshift_timeout) {
@@ -169,16 +160,23 @@ static void autoshift_end(uint16_t keycode, uint16_t now, bool matrix_trigger) {
  *  to be released.
  */
 void autoshift_matrix_scan(void) {
-    if (
+    if (autoshift_flags.in_progress) {
+        const uint16_t now     = timer_read();
 #    ifdef RETRO_SHIFT
-        retroshift_lastkey == KC_NO &&
+        if (retroshift_lastkey == KC_NO) {
 #    endif
-        autoshift_flags.in_progress) {
-        const uint16_t now     = timer_read();
-        const uint16_t elapsed = TIMER_DIFF_16(now, autoshift_time);
-        if (elapsed >= autoshift_timeout) {
-            autoshift_end(autoshift_lastkey, now, true);
+            if (TIMER_DIFF_16(now, autoshift_time) >= autoshift_timeout) {
+                autoshift_end(autoshift_lastkey, now, true);
+            }
+#    ifdef RETRO_SHIFT
+        } else {
+            if ((RETRO_SHIFT + 0) != 0 && TIMER_DIFF_16(now, retroshift_time) > (RETRO_SHIFT + 0)) {
+                process_record_handler(&retro_record);
+                autoshift_flags.in_progress = false;
+                retroshift_lastkey = KC_NO;
+            }
         }
+#    endif
     }
 }
 
@@ -221,26 +219,37 @@ bool process_auto_shift(uint16_t keycode, keyrecord_t *record) {
             // Keyrepeat, the down event already happened.
             return false;
         }
-        // The in_progress check prevents this from triggering on a keyrepeating
         // Retro Shifted key and pressing its usual hold action.
-        if (retroshift_lastkey != KC_NO && autoshift_flags.in_progress) {
-            // Trigger Tap Hold key's hold action which we stopped earlier.
-            process_record_handler(&retro_record);
+        if (retroshift_lastkey != KC_NO) {
+            if ((RETRO_SHIFT + 0) == 0) {
+                process_record_handler(&retro_record);
+                autoshift_flags.in_progress = false;
+            }
+#        ifdef IGNORE_MOD_TAP_INTERRUPT
+            else if (autoshift_flags.in_progress && TIMER_DIFF_16(now, retroshift_time) < (RETRO_SHIFT + 0)) {
+                autoshift_time = retroshift_time;
+                autoshift_lastkey = retroshift_lastkey;
+                autoshift_end(autoshift_lastkey, now, false);
+            }
+#        endif
             retroshift_lastkey = KC_NO;
-            autoshift_flags.in_progress = false;
         }
         if ((keycode >= QK_MOD_TAP && keycode <= QK_MOD_TAP_MAX) || (keycode >= QK_LAYER_TAP && keycode <= QK_LAYER_TAP_MAX) || (keycode >= QK_MODS && keycode <= QK_MODS_MAX)) {
+            if (autoshift_flags.in_progress) {
+                autoshift_end(KC_NO, now, false);
+            }
 #        ifdef RETRO_TAPPING_PER_KEY
             if (!get_retro_tapping(get_event_keycode(record->event, false), record)) {
                 return true;
             }
 #        endif
-            if (autoshift_flags.in_progress) {
-                autoshift_end(KC_NO, now, false);
+            if (record->tap.interrupted) {
+                return true;
+            } else {
+                retroshift_lastkey = keycode;
+                retro_repeat = record->event.key;
+                retro_record = *record;
             }
-            retroshift_lastkey = keycode;
-            retro_repeat = record->event.key;
-            retro_record = *record;
         }
 #    endif
         if (autoshift_flags.in_progress) {
@@ -279,19 +288,29 @@ bool process_auto_shift(uint16_t keycode, keyrecord_t *record) {
 #    ifdef RETRO_SHIFT
     else if (keycode == retroshift_lastkey) {
         // Retro Shift key was tapped/held or keyrepeated (handled by us).
-        autoshift_end(keycode, now, false);
-        retroshift_lastkey = KC_NO;
+        if (!((RETRO_SHIFT + 0) != 0 && TIMER_DIFF_16(now, retroshift_time) > (RETRO_SHIFT + 0))) {
+            autoshift_time = retroshift_time;
+            autoshift_lastkey = retroshift_lastkey;
+            autoshift_end(keycode, now, false);
+            retroshift_lastkey = KC_NO;
+            return false;
+        } else {
+            // Hold release action needs to happen.
+            return true;
+        }
     } else if ((keycode >= QK_MOD_TAP && keycode <= QK_MOD_TAP_MAX) || (keycode >= QK_LAYER_TAP && keycode <= QK_LAYER_TAP_MAX) || (keycode >= QK_MODS && keycode <= QK_MODS_MAX)) {
-        // Could also be a keyrepeat end. This being here could cause weird
-        // behavior, but I cannot think of a better way to handle it as we would
-        // need to store keyrepeat status per Tap Hold key.
-        // Eg. using CTRL_T(KC_A) as a mod on KC_A and releasing CTRL_T would
-        // also release KC_A.
-        autoshift_end(keycode, now, false);
-        // The Tap Hold key was either interrupted or is not an Auto Shift key
-        // (or was cancelled by RETRO_TAPPING_PER_KEY). Regardless, its hold
-        // release action needs to happen so we return true.
-        return true;
+        // The Tap Hold key was interrupted, is not an Auto Shift key, was
+        // cancelled by RETRO_TAPPING_PER_KEY, or RETRO_SHIFT was exceeded.
+        if (record->tap.count == 1 && !((RETRO_SHIFT + 0) != 0 && TIMER_DIFF_16(now, retroshift_time) > (RETRO_SHIFT + 0))) {
+#        ifdef RETRO_TAPPING_PER_KEY
+            if (!get_retro_tapping(get_event_keycode(record->event, false), record)) {
+                return true;
+            }
+#        endif
+        } else {
+            // Hold release action needs to happen.
+            return true;
+        }
     }
 #    endif
 
@@ -314,6 +333,7 @@ bool process_auto_shift(uint16_t keycode, keyrecord_t *record) {
                 return false;
             }
     }
+    autoshift_lastkey = KC_NO;
 #    ifdef RETRO_SHIFT
     retroshift_lastkey = KC_NO;
 #    endif