include_str to watch TOML file

oximeter/timeseries-macro/Cargo.toml

@@ -9,6 +9,7 @@ proc-macro = true
 [dependencies]
 oximeter-impl.workspace = true
 proc-macro2.workspace = true
+quote.workspace = true
 syn.workspace = true
 
 [lints]

oximeter/timeseries-macro/src/lib.rs

@@ -6,7 +6,20 @@ pub fn use_timeseries(
 ) -> proc_macro::TokenStream {
     match syn::parse::<syn::LitStr>(tokens) {
         Ok(path) => {
-            let filename = path.value();
+            let filename =
+                match std::path::Path::new(&path.value()).canonicalize() {
+                    Ok(f) => f.display().to_string(),
+                    Err(e) => {
+                        let msg = format!(
+                            "Failed to canonicalize file from path '{}': {:?}",
+                            path.value(),
+                            e,
+                        );
+                        return syn::Error::new(path.span(), msg)
+                            .into_compile_error()
+                            .into();
+                    }
+                };
             let contents = match std::fs::read_to_string(&filename) {
                 Ok(c) => c,
                 Err(e) => {
@@ -21,7 +34,15 @@ pub fn use_timeseries(
                 }
             };
             match oximeter_impl::schema::codegen::use_timeseries(&contents) {
-                Ok(toks) => return toks.into(),
+                Ok(toks) => {
+                    return quote::quote! {
+                        /// Include the schema file itself to ensure we recompile
+                        /// when that changes.
+                        const _: &str = include_str!(#filename);
+                        #toks
+                    }
+                    .into()
+                }
                 Err(e) => {
                     let msg = format!(
                         "Failed to generate timeseries types \