test: add fixtures to test function codegen

frb_codegen/Cargo.toml

@@ -55,6 +55,7 @@ notify = "6.1.1"
 notify-debouncer-mini = "0.4.1"
 
 [dev-dependencies]
+pretty_assertions = "1.4.0"
 semver = "1.0.12"
 
 [package.metadata.binstall]

frb_codegen/src/library/codegen/generator/api_dart/mod.rs

@@ -56,6 +56,12 @@ mod tests {
         body("library/codegen/generator/api_dart/mod/simple")
     }
 
+    #[test]
+    #[serial]
+    fn test_functions() -> anyhow::Result<()> {
+        body("library/codegen/generator/api_dart/mod/functions")
+    }
+
     fn body(fixture_name: &str) -> anyhow::Result<()> {
         configure_opinionated_test_logging();
         let test_fixture_dir = get_test_fixture_dir(fixture_name);

frb_codegen/src/library/commands/cargo_expand.rs

@@ -2,14 +2,17 @@ use crate::codegen::dumper::Dumper;
 use crate::codegen::ConfigDumpContent;
 use crate::command_args;
 use crate::library::commands::command_runner::execute_command;
+
 use anyhow::{bail, Context, Result};
 use itertools::Itertools;
+use lazy_static::lazy_static;
 use log::{debug, info, warn};
 use regex::Regex;
+
+use std::borrow::Cow;
 use std::collections::hash_map::Entry::{Occupied, Vacant};
 use std::collections::HashMap;
 use std::path::{Path, PathBuf};
-use std::sync::OnceLock;
 use std::{env, fs};
 
 #[derive(Default)]
@@ -41,7 +44,10 @@ impl CachedCargoExpand {
 
         let expanded = match self.cache.entry(rust_crate_dir.to_owned()) {
             Occupied(entry) => entry.into_mut(),
-            Vacant(entry) => entry.insert(run_cargo_expand(rust_crate_dir, dumper, true)?),
+            Vacant(entry) => entry.insert(
+                unwrap_frb_attrs_in_doc(&run_cargo_expand(rust_crate_dir, dumper, true)?)
+                    .into_owned(),
+            ),
         };
 
         extract_module(expanded, module)
@@ -93,7 +99,7 @@ fn run_cargo_expand(
         "--theme=none",
         "--ugly",
         "--config",
-        "build.rustflags=\"--cfg frb_expand\""
+        r#"build.rustflags="--cfg frb_expand""#
     );
 
     let output = execute_command("cargo", &args, Some(rust_crate_dir), None)
@@ -114,20 +120,22 @@ fn run_cargo_expand(
         // frb-coverage:ignore-end
     }
 
-    let mut stdout_lines = stdout.lines();
-    stdout_lines.next();
-    let ans = stdout_lines.join("\n");
-    static PATTERN: OnceLock<Regex> = OnceLock::new();
-    let pattern = PATTERN.get_or_init(|| {
-        Regex::new(r####"#\[doc =[\s\n]*r###"frb_marker: ([\s\S]*?)"###]"####).unwrap()
-    });
-    let ans = pattern.replace_all(&ans, "$1").into_owned();
-
+    let ans = stdout.lines().skip(1).join("\n");
     dumper.dump_str(ConfigDumpContent::Source, "cargo_expand.rs", &ans)?;
-
     Ok(ans)
 }
 
+/// Turns `#[doc = "frb_marker: .."]` back into `#[frb(..)]`, usually produced
+/// as a side-effect of cargo-expand.
+// NOTE: The amount of pounds must match exactly with the implementation in frb_macros
+fn unwrap_frb_attrs_in_doc(code: &str) -> Cow<str> {
+    lazy_static! {
+        static ref PATTERN: Regex =
+            Regex::new(r####"#\[doc =[\s\n]*r###"frb_marker: ([\s\S]*?)"###]"####).unwrap();
+    }
+    PATTERN.replace_all(code, "$1")
+}
+
 fn install_cargo_expand() -> Result<()> {
     execute_command(
         "cargo",

frb_codegen/src/library/commands/command_runner.rs

@@ -38,7 +38,7 @@ macro_rules! command_run {
     }};
 }
 
-/// Formats a list of [`PathBuf`]s using the syntax detailed in [`run`].
+/// Formats a list of [`PathBuf`]s using the syntax detailed in [`command_run`].
 #[doc(hidden)]
 #[macro_export]
 macro_rules! command_args {

frb_codegen/src/library/utils/test_utils.rs

@@ -28,28 +28,43 @@ pub(crate) fn json_golden_test(
     let actual: Value = serde_json::from_str(&actual_str)?;
     debug!("json_golden_test sanitizers={sanitizers:?} actual:\n{actual_str}");
 
-    raw_golden_test(actual, &actual_str, matcher_path, |x| {
-        Ok(serde_json::from_str(&x)?)
-    })
+    raw_golden_test(
+        actual,
+        &actual_str,
+        matcher_path,
+        |x| Ok(serde_json::from_str(&x)?),
+        None,
+    )
 }
 
 pub(crate) fn text_golden_test(actual: String, matcher_path: &Path) -> anyhow::Result<()> {
-    raw_golden_test(actual.clone(), &actual, matcher_path, |x| {
+    raw_golden_test(
+        actual.clone(),
+        &actual,
+        matcher_path,
         // Otherwise tests in macos/linux passes but fails on windows
-        Ok(x.replace("\r\n", "\n"))
-    })
+        |x| Ok(x.replace("\r\n", "\n")),
+        Some(|expect, actual| {
+            #[cfg(test)]
+            use pretty_assertions::assert_str_eq as assert_eq;
+            assert_eq!(expect, actual);
+        }),
+    )
 }
 
 fn raw_golden_test<T, F>(
     actual: T,
     actual_str: &str,
     matcher_path: &Path,
     deserializer: F,
+    asserter: Option<fn(&T, &T)>,
 ) -> anyhow::Result<()>
 where
     T: Eq + Debug,
     F: Fn(String) -> anyhow::Result<T>,
 {
+    #[cfg(test)]
+    use pretty_assertions::assert_eq;
     // This is *test* utils, not a part of real codegen, so no need to consider coverage
     // frb-coverage:ignore-start
     let expect = deserializer(if matcher_path.exists() {
@@ -64,7 +79,8 @@ where
             fs::write(matcher_path, actual_str)?;
         }
     } else {
-        assert_eq!(actual, expect);
+        let asserter = asserter.unwrap_or(|expect, actual| assert_eq!(expect, actual));
+        asserter(&expect, &actual);
     }
 
     Ok(())

frb_codegen/test_fixtures/library/codegen/generator/api_dart/mod/functions/Cargo.toml

@@ -0,0 +1,11 @@
+[package]
+name = "example"
+version = "0.1.0"
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+flutter_rust_bridge_macros.path = "../../../../../../../../frb_macros"
+
+[workspace]

frb_codegen/test_fixtures/library/codegen/generator/api_dart/mod/functions/expect_output.dart

@@ -0,0 +1,14 @@
+
+        // This file is automatically generated, so please do not edit it.
+// Generated by `flutter_rust_bridge`@ {VERSION}.
+
+// ignore_for_file: invalid_use_of_internal_member, unused_import, unnecessary_import
+
+import 'frb_generated.dart';
+import 'package:flutter_rust_bridge/flutter_rust_bridge_for_generated.dart';
+
+
+        Future<void> fnWithDefaultArg({int foo = 1, dynamic hint}) => RustLib.instance.api.fnWithDefaultArg(foo: foo, hint: hint);
+
+
+

frb_codegen/test_fixtures/library/codegen/generator/api_dart/mod/functions/flutter_rust_bridge.yaml

@@ -0,0 +1,3 @@
+rust_input: src/api.rs
+dart_output: .
+c_output: frb_generated.h

frb_codegen/test_fixtures/library/codegen/generator/api_dart/mod/functions/pubspec.yaml

@@ -0,0 +1 @@
+name: fake_dart_package

frb_codegen/test_fixtures/library/codegen/generator/api_dart/mod/functions/src/api.rs

@@ -0,0 +1,4 @@
+#[flutter_rust_bridge_macros::frb]
+pub fn fn_with_default_arg(#[frb(default = 1)] foo: i32) {
+    drop(foo);
+}

frb_codegen/test_fixtures/library/codegen/generator/api_dart/mod/functions/src/lib.rs

@@ -0,0 +1 @@
+mod api;

frb_macros/src/lib.rs

@@ -10,10 +10,10 @@ use proc_macro::*;
 // frb-coverage:ignore-start
 #[proc_macro_attribute]
 pub fn frb(attribute: TokenStream, item: TokenStream) -> TokenStream {
-    let mut attribute = format_frb_attribute(format!("#[frb({attribute})]"));
+    let mut output = format_frb_attribute(format!("#[frb({attribute})]"));
     let item = strip_frb_attr(item);
-    attribute.extend(item);
-    attribute
+    output.extend(item);
+    output
 }
 
 fn strip_frb_attr(item: TokenStream) -> TokenStream {
@@ -30,14 +30,16 @@ fn strip_frb_attr(item: TokenStream) -> TokenStream {
                     Some(format_frb_attribute(format!("#[{}]", group.stream())))
                 }
                 (_, T::Group(group)) => Some(
-                    pound
-                        .take()
-                        .into_iter()
-                        .chain(Some(T::Group(Group::new(
+                    [
+                        pound.take(),
+                        Some(T::Group(Group::new(
                             group.delimiter(),
                             strip_frb_attr(group.stream()),
-                        ))))
-                        .collect(),
+                        ))),
+                    ]
+                    .into_iter()
+                    .flatten()
+                    .collect(),
                 ),
                 _ => Some(tok.into()),
             }

justfile

@@ -27,5 +27,5 @@ _port_forward_ubuntu:
     ssh -L 8181:localhost:8181 ubuntu -N
 
 [no-cd]
-expand *args:
+_expand *args:
     cargo expand --config 'build.rustflags="--cfg frb_expand"' {{args}}