From 0c85905972fdc739fb140e32c3389c08e769bfff Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Daniel=20Ekl=C3=B6f?= <daniel@ekloef.se>
Date: Sun, 21 Mar 2021 11:55:03 +0100
Subject: [PATCH] input: must have all required modifiers to un-shift a symbol
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When detecting, and repairing, “broken” key bindings (where the key
binding itself explicitly lists a modifier that is consumed by the
final symbol - e.g “Shift+W”), don’t just look for an intersection
between the set of modifiers needed to produce the final symbol, and
the modifiers listed in the key combo. Instead, check if the key combo
has *all* the required modifiers.

Example: Shift+AltGr+w produces Page_Down. I.e. Page_Down is the
_shifted_ symbol, ‘w’ is the un-shifted symbol, and Shift+AltGr are
the modifiers required to shift ‘w’ to Page_Down.

If we have the key combo Shift+Page_Down, foot would, correctly,
determine that Page_Down is a shifted symbol. It would find the
Shift+AltGr modifier set, and since the intersection of “Shift+AltGr”
and “Shift” (from our key combo) is non-empty, foot
would (incorrectly) determine that we can, and should, replace
Page_Down with its un-shifted symbol ‘w’.

This is completely wrong, since Shift+w does _not_ produce Page_Down.

Closes #407
---
 CHANGELOG.md | 5 +++++
 input.c      | 2 +-
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 46e3a5b8..266d9b77 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -30,6 +30,11 @@
 ### Deprecated
 ### Removed
 ### Fixed
+
+* Logic that repairs invalid key bindings ended up breaking valid key
+  bindings instead (https://codeberg.org/dnkl/foot/issues/407).
+
+
 ### Security
 ### Contributors
 
diff --git a/input.c b/input.c
index bc28bbf2..9a26e778 100644
--- a/input.c
+++ b/input.c
@@ -450,7 +450,7 @@ maybe_repair_key_combo(const struct seat *seat,
 
                 /* Check if key combo’s modifier set intersects */
                 for (size_t j = 0; j < mod_mask_count; j++) {
-                    if (!(mod_masks[j] & mods))
+                    if ((mod_masks[j] & mods) != mod_masks[j])
                         continue;
 
                     char combo[64] = {0};