Merge branch 'error-on-empty-key-or-mouse-binding'

Closes #851

CHANGELOG.md

@@ -62,6 +62,8 @@
   CSI codes in the Kitty keyboard protocol.
 * Assertion in `shm.c:buffer_release()`
   (https://codeberg.org/dnkl/foot/issues/844).
+* Crash when setting a key- or mouse binding to the empty string
+  (https://codeberg.org/dnkl/foot/issues/851).
 
 
 ### Security

config.c

@@ -1726,6 +1726,12 @@ value_to_key_combos(struct context *ctx, int action, struct argv *argv,
 
     }
 
+    if (idx == 0) {
+        LOG_CONTEXTUAL_ERR(
+            "empty binding not allowed (set to 'none' to unmap)");
+        goto err;
+    }
+
     remove_from_key_bindings_list(bindings, action, argv);
 
     bindings->arr = xrealloc(

tests/test-config.c

@@ -296,7 +296,16 @@ test_key_binding(struct context *ctx, bool (*parse_fun)(struct context *ctx),
     const int click_count = action % 3 + 1;
 
     /* Finally, generate the ‘value’ (e.g. “Control+shift+x”) */
-    char value[128];
+    char value[128] = {0};
+
+    ctx->key = key;
+    ctx->value = value;
+
+    /* First, try setting the empty string */
+    if (parse_fun(ctx)) {
+        BUG("[%s].%s=<empty>: did not fail to parse as expected",
+            ctx->section, ctx->key);
+    }
 
     switch (type) {
     case KEY_BINDING: {
@@ -319,9 +328,6 @@ test_key_binding(struct context *ctx, bool (*parse_fun)(struct context *ctx),
     }
     }
 
-    ctx->key = key;
-    ctx->value = value;
-
     if (!parse_fun(ctx)) {
         BUG("[%s].%s=%s failed to parse",
             ctx->section, ctx->key, ctx->value);