log,doc: more defsrc warnings

docs/config.adoc

@@ -369,12 +369,16 @@ This might be useful
 if you are only mapping a few keys in defsrc
 instead of most of the keys on your keyboard.
 
-Without this, some actions like `+rpt+`, `+tap-hold-release+`, `+one-shot+`,
-will not work correctly for subsequent key presses that are not in defsrc.
+By default, keys excluded from `defsrc` will not work in various scenarios.
+Some examples of when a not-in-defsrc key is pressed:
+
+- antecedent `+tap-hold-press+` activations will not trigger an early hold
+- antecedent `+one-shot+` activations will not be released
+- `fork|switch` logic will not be able to see the key
 
 This option is disabled by default.
-The reason this is not enabled by default is
-because some keys may not work correctly if they are intercepted.
+The reason this is not enabled by default
+is because some keys may not work correctly if they are intercepted.
 For example, see <<windows-only-windows-altgr>>.
 
 .Example:

parser/src/cfg/defcfg.rs

@@ -176,11 +176,17 @@ pub fn parse_defcfg(expr: &[SExpr]) -> Result<CfgOptions> {
     let mut seen_keys = HashSet::default();
     let mut cfg = CfgOptions::default();
     let mut exprs = check_first_expr(expr.iter(), "defcfg")?;
+    let mut is_process_unmapped_keys_defined = false;
     // Read k-v pairs from the configuration
     loop {
         let key = match exprs.next() {
             Some(k) => k,
-            None => return Ok(cfg),
+            None => {
+                if !is_process_unmapped_keys_defined {
+                    log::warn!("The item process-unmapped-keys is not defined in defcfg. Consider whether process-unmapped-keys should be yes vs. no.");
+                }
+                return Ok(cfg);
+            }
         };
         let val = match exprs.next() {
             Some(v) => v,
@@ -603,6 +609,7 @@ pub fn parse_defcfg(expr: &[SExpr]) -> Result<CfgOptions> {
                     }
 
                     "process-unmapped-keys" => {
+                        is_process_unmapped_keys_defined = true;
                         cfg.process_unmapped_keys = parse_defcfg_val_bool(val, label)?
                     }
                     "block-unmapped-keys" => {

parser/src/cfg/mod.rs

@@ -611,7 +611,10 @@ pub fn parse_cfg_raw_string(
         .find(gen_first_atom_filter("defcfg"))
         .map(|cfg| parse_defcfg(cfg))
         .transpose()?
-        .unwrap_or_default();
+        .unwrap_or_else(|| {
+            log::warn!("No defcfg is defined. Consider whether the process-unmapped-keys defcfg option should be yes vs. no. Adding defcfg with process-unmapped-keys defined will remove this warning.");
+            Default::default()
+        });
     if let Some(spanned) = spanned_root_exprs
         .iter()
         .filter(gen_first_atom_filter_spanned("defcfg"))