feat(render): improve error log when variable is missing in forms

espanso-render/src/renderer/mod.rs

@@ -126,21 +126,7 @@ impl<'a> Renderer for DefaultRenderer<'a> {
                   if let Some(RendererError::MissingVariable(_)) =
                     err.downcast_ref::<RendererError>()
                   {
-                    error!("");
-                    error!("TIP: This error might be happening because since version 2.1.0-alpha, Espanso changed");
-                    error!("the syntax to define form controls. Instead of `{{{{control}}}}` you need to use");
-                    error!("[[control]] (using square brackets instead of curly brackets).");
-                    error!("");
-                    error!("For example, you have a form defined like the following:");
-                    error!("  - trigger: test");
-                    error!("    form: |");
-                    error!("      Hi {{{{name}}}}!");
-                    error!("");
-                    error!("You'll need to replace it with:");
-                    error!("  - trigger: test");
-                    error!("    form: |");
-                    error!("      Hi [[name]]!");
-                    error!("");
+                    log_new_form_syntax_tip();
                   }
                 }
 
@@ -236,6 +222,24 @@ fn get_matching_template<'a>(
   }
 }
 
+fn log_new_form_syntax_tip() {
+  error!("");
+  error!("TIP: This error might be happening because since version 2.1.0-alpha, Espanso changed");
+  error!("the syntax to define form controls. Instead of `{{{{control}}}}` you need to use");
+  error!("[[control]] (using square brackets instead of curly brackets).");
+  error!("");
+  error!("For example, if you have a form defined like the following:");
+  error!("  - trigger: test");
+  error!("    form: |");
+  error!("      Hi {{{{name}}}}!");
+  error!("");
+  error!("You'll need to replace it with:");
+  error!("  - trigger: test");
+  error!("    form: |");
+  error!("      Hi [[name]]!");
+  error!("");
+}
+
 #[derive(Error, Debug)]
 pub enum RendererError {
   #[error("missing variable: `{0}`")]

espanso-render/src/renderer/resolve.rs

@@ -23,6 +23,7 @@ use std::{
 };
 
 use anyhow::{anyhow, Result};
+use log::error;
 
 use crate::Variable;
 
@@ -179,6 +180,12 @@ fn resolve_dependencies<'a>(
             resolve_dependencies(dependency_node, node_map, eval_order, resolved, seen)?
           }
           None => {
+            error!("could not resolve variable {:?}", dependency);
+            if let Some(variable) = &node.variable {
+              if variable.var_type == "form" {
+                super::log_new_form_syntax_tip();
+              }
+            }
             return Err(RendererError::MissingVariable(dependency.to_string()).into());
           }
         }