Code generation gets stuck if .fvmrc contains flutter version that's invalid

[prateekmedia]

Describe the bug

When .fvmrc contains a flutter version that's not present in the system, it gets stuck indefinitely, no errors no warnings.

Steps to reproduce

1. .fvmrc

{
  "flutter": "3.32.9"
}

There is no flutter version with 3.32.9 as of writing, you can also try this with a flutter version that's not installed through fvm.

2. Now when I run this command it gets stuck infinitely without any warning or message, which makes it confusing that what could be the problem.

flutter_rust_bridge_codegen generate 

Logs

[2025-08-24T14:56:01.260Z DEBUG ~/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/flutter_rust_bridge_codegen-2.11.1/src/main.rs:25] cli=Cli { verbose: false, command: Generate(GenerateCommandArgs { watch: false, primary: GenerateCommandArgsPrimary { config_file: None, rust_input: None, dart_output: None, c_output: None, duplicated_c_output: None, rust_root: None, rust_output: None, dart_entrypoint_class_name: None, dart_format_line_length: None, dart_preamble: None, rust_preamble: None, no_dart_enums_style: false, no_add_mod_to_lib: false, llvm_path: None, llvm_compiler_opts: None, dart_root: None, no_build_runner: false, extra_headers: None, no_web: false, no_deps_check: false, default_external_library_loader_web_prefix: None, no_dart3: false, full_dep: false, default_rust_opaque_codec: None, local: false, enable_lifetime: false, type_64bit_int: false, no_default_dart_async: false, no_auto_upgrade_dependency: false, parse_const: false, no_dart_format: false, no_dart_fix: false, no_rust_format: false, stop_on_error: false, dump: None, dump_all: false, rust_features: None } }) }
[2025-08-24T14:56:01.261Z DEBUG ~/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/flutter_rust_bridge_codegen-2.11.1/src/library/codegen/config/config_parser.rs:51] Found config file flutter_rust_bridge.yaml
[2025-08-24T14:56:01.262Z DEBUG ~/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/flutter_rust_bridge_codegen-2.11.1/src/library/codegen/mod.rs:24] config=Config { base_dir: Some(""), rust_input: Some("crate::api"), dart_output: Some("lib/src/rust"), c_output: None, duplicated_c_output: None, rust_root: Some("rust/"), rust_output: None, dart_entrypoint_class_name: None, dart_format_line_length: None, dart_preamble: Some("// ignore_for_file: require_trailing_commas\n"), rust_preamble: None, dart_enums_style: None, add_mod_to_lib: None, llvm_path: None, llvm_compiler_opts: None, dart_root: None, build_runner: None, extra_headers: None, web: Some(false), deps_check: None, dart3: None, full_dep: None, default_rust_opaque_codec: None, local: None, default_external_library_loader_web_prefix: None, dart_type_rename: None, enable_lifetime: None, type_64bit_int: None, default_dart_async: None, auto_upgrade_dependency: None, parse_const: None, dart_format: None, dart_fix: None, rust_format: None, stop_on_error: None, dump: None, dump_all: None, rust_features: None } meta_config=MetaConfig { watch: false }
[2025-08-24T14:56:01.262Z DEBUG ~/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/flutter_rust_bridge_codegen-2.11.1/src/library/codegen/config/internal_config_parser/mod.rs:34] InternalConfig.parse base_dir="~/dev/enteio/ente/mobile/apps/photos"
[2025-08-24T14:56:01.634Z DEBUG ~/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/flutter_rust_bridge_codegen-2.11.1/src/library/codegen/mod.rs:27] internal_config=InternalConfig { controller: ControllerInternalConfig { watch: false, watching_paths: ["~/dev/enteio/ente/mobile/apps/photos/rust/src"], exclude_paths: ["~/dev/enteio/ente/mobile/apps/photos/rust/src/frb_generated.rs"], max_count: None }, preparer: PreparerInternalConfig { dart_root: "~/dev/enteio/ente/mobile/apps/photos", deps_check: true, needs_ffigen: false }, parser: ParserInternalConfig { hir: ParserHirInternalConfig { rust_input_namespace_pack: RustInputNamespacePack { rust_input_namespace_prefixes: [Namespace { joined_path: "crate::api" }], rust_output_path_namespace: Namespace { joined_path: "crate::frb_generated" } }, rust_crate_dir: "~/dev/enteio/ente/mobile/apps/photos/rust", third_party_crate_names: [], rust_features: None, parse_const: false }, mir: ParserMirInternalConfig { rust_input_namespace_pack: RustInputNamespacePack { rust_input_namespace_prefixes: [Namespace { joined_path: "crate::api" }], rust_output_path_namespace: Namespace { joined_path: "crate::frb_generated" } }, force_codec_mode_pack: Some(CodecModePack { dart2rust: Pde, rust2dart: Pde }), default_stream_sink_codec: Sse, default_rust_opaque_codec: Moi, stop_on_error: false, enable_lifetime: false, type_64bit_int: false, default_dart_async: true } }, generator: GeneratorInternalConfig { api_dart: GeneratorApiDartInternalConfig { dart_enums_style: true, dart3: true, dart_decl_base_output_path: "~/dev/enteio/ente/mobile/apps/photos/lib/src/rust", dart_impl_output_path: TargetOrCommonMap { common: "~/dev/enteio/ente/mobile/apps/photos/lib/src/rust/frb_generated.dart", io: "~/dev/enteio/ente/mobile/apps/photos/lib/src/rust/frb_generated.io.dart", web: "~/dev/enteio/ente/mobile/apps/photos/lib/src/rust/frb_generated.web.dart" }, dart_entrypoint_class_name: "RustLib", dart_preamble: "// ignore_for_file: require_trailing_commas\n", dart_type_rename: {} }, wire: GeneratorWireInternalConfig { dart: GeneratorWireDartInternalConfig { has_ffigen: false, web_enabled: false, llvm_path: ["/opt/homebrew/opt/llvm", "/usr/local/opt/llvm", "/usr/lib/llvm-9", "/usr/lib/llvm-10", "/usr/lib/llvm-11", "/usr/lib/llvm-12", "/usr/lib/llvm-13", "/usr/lib/llvm-14", "/usr/lib/", "/usr/lib64/", "C:/Program Files/llvm", "C:/msys64/mingw64"], llvm_compiler_opts: "", dart_root: "~/dev/enteio/ente/mobile/apps/photos", extra_headers: "", dart_impl_output_path: TargetOrCommonMap { common: "~/dev/enteio/ente/mobile/apps/photos/lib/src/rust/frb_generated.dart", io: "~/dev/enteio/ente/mobile/apps/photos/lib/src/rust/frb_generated.io.dart", web: "~/dev/enteio/ente/mobile/apps/photos/lib/src/rust/frb_generated.web.dart" }, dart_output_class_name_pack: DartOutputClassNamePack { entrypoint_class_name: "RustLib", api_class_name: "RustLibApi", api_impl_class_name: "RustLibApiImpl", api_impl_platform_class_name: "RustLibApiImplPlatform", wire_class_name: "RustLibWire", wasm_module_name: "RustLibWasmModule" }, default_external_library_loader: GeneratorWireDartDefaultExternalLibraryLoaderInternalConfig { stem: "rust_lib_photos", io_directory: "rust/target/release/", web_prefix: "pkg/" }, c_symbol_prefix: "frbgen_photos_" }, rust: GeneratorWireRustInternalConfig { rust_crate_dir: "~/dev/enteio/ente/mobile/apps/photos/rust", web_enabled: false, rust_output_path: "~/dev/enteio/ente/mobile/apps/photos/rust/src/frb_generated.rs", c_symbol_prefix: "frbgen_photos_", has_ffigen: false, default_stream_sink_codec: Sse, default_rust_opaque_codec: Moi, rust_preamble: "" }, c: GeneratorWireCInternalConfig { enable: false, rust_crate_dir: "~/dev/enteio/ente/mobile/apps/photos/rust", rust_output_path: "~/dev/enteio/ente/mobile/apps/photos/rust/src/frb_generated.rs", c_output_path: None, c_symbol_prefix: "frbgen_photos_" } } }, polisher: PolisherInternalConfig { duplicated_c_output_path: [], dart_format_line_length: 80, dart_format: true, dart_fix: true, rust_format: true, add_mod_to_lib: true, build_runner: true, web_enabled: false, dart_output: "~/dev/enteio/ente/mobile/apps/photos/lib/src/rust", dart_root: "~/dev/enteio/ente/mobile/apps/photos", rust_crate_dir: "~/dev/enteio/ente/mobile/apps/photos/rust", rust_output_path: "~/dev/enteio/ente/mobile/apps/photos/rust/src/frb_generated.rs", c_output_path: None, enable_auto_upgrade: true }, dumper: DumperInternalConfig { dump_contents: [], dump_directory: "~/dev/enteio/ente/mobile/apps/photos/rust/target/frb_dump" } }
[2025-08-24T14:56:01.635Z DEBUG ~/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/flutter_rust_bridge_codegen-2.11.1/src/library/utils/dart_repository/dart_repo.rs:21] Guessing toolchain the runner is run into
[2025-08-24T14:56:01.635Z DEBUG ~/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/flutter_rust_bridge_codegen-2.11.1/src/library/commands/command_runner.rs:137] execute command: bin=sh args="-c \"fvm\" \"--version\"" current_dir=None cmd="sh" "-c" "\"fvm\" \"--version\""
[2025-08-24T14:56:01.677Z DEBUG ~/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/flutter_rust_bridge_codegen-2.11.1/src/library/commands/command_runner.rs:148] command="sh" "-c" "\"fvm\" \"--version\"" stdout=3.2.1
 stderr=
[2025-08-24T14:56:01.677Z DEBUG ~/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/flutter_rust_bridge_codegen-2.11.1/src/library/commands/command_runner.rs:137] execute command: bin=sh args="-c \"fvm\" \"flutter\" \"--version\"" current_dir=None cmd="sh" "-c" "\"fvm\" \"flutter\" \"--version\""

Expected behavior

It should exit and show me why things are not good for proceed.

Generated binding code

OS

No response

Version of flutter_rust_bridge_codegen

No response

Flutter info

Version of clang++

No response

Additional context

No response

[fzyzcjy]

hmm I wonder whether this is related: #2834

Could you please try the latest main branch and see whether it works?

[prateekmedia]

@fzyzcjy How can I compile main to test? I tried cargo build in frb_rust but it didn't worked.

[fzyzcjy]

just clone the project, and treat https://github.com/fzyzcjy/flutter_rust_bridge/tree/master/frb_codegen as a normal rust project with a binary executable, e.g. I guess cargo run ...

[prateekmedia]

Good news: If value is valid of flutter version in .fvmrc it works, by first installing flutter version specified.
Bad news: If value is invalid (like in my random example) then it is still stuck

I would like if the bad news case is resolved, but atleast any valid .fvmrc it won't get stuck. You may close this if you feel like Bad news case is not important.

Thanks, waiting for new release!

[fzyzcjy]

You are welcome and happy to see it works on main!