Defer escape bindings as well

This allows rebinding escape in the user list without breaking e.g.
arrow keys (which send escape and then `[A` and similar, so escape is
a prefix of them).

Fixes #8428.

src/input.cpp

@@ -597,6 +597,7 @@ maybe_t<input_mapping_t> inputter_t::find_mapping(event_queue_peeker_t *peeker)
     const input_mapping_t *generic = nullptr;
     const auto &vars = parser_->vars();
     const wcstring bind_mode = input_get_bind_mode(vars);
+    const input_mapping_t *escape = nullptr;
 
     auto ml = input_mappings()->all_mappings();
     for (const auto &m : *ml) {
@@ -611,10 +612,25 @@ maybe_t<input_mapping_t> inputter_t::find_mapping(event_queue_peeker_t *peeker)
         }
 
         if (try_peek_sequence(peeker, m.seq)) {
-            return m;
+            // A binding for just escape should also be deferred
+            // so escape sequences take precedence.
+            if (m.seq == L"\x1B") {
+                if (!escape) {
+                    escape = &m;
+                }
+            } else {
+                return m;
+            }
         }
         peeker->restart();
     }
+
+    if (escape) {
+        // We need to reconsume the escape.
+        peeker->next();
+        return *escape;
+    }
+
     return generic ? maybe_t<input_mapping_t>(*generic) : none();
 }
 

tests/pexpects/bind.py

@@ -319,6 +319,17 @@ send("\x07")  # ctrl-g, kill bigword
 sendline("echo")
 expect_prompt("\nb c d")
 
+# Test that overriding the escape binding works
+# and does not inhibit other escape sequences (up-arrow in this case).
+sendline("bind \\x1b 'echo foo'")
+expect_prompt()
+send("\x1b")
+expect_str("foo")
+send("\x1b[A")
+expect_str("bind \\x1b 'echo foo'")
+sendline("")
+expect_prompt()
+
 send("    a b c d\x01")  # ctrl-a, move back to the beginning of the line
 send("\x07")  # ctrl-g, kill bigword
 sendline("echo")