src/tools/rust-analyzer/crates/rust-analyzer/src/reload.rs

   1 //! Project loading & configuration updates.
   2 //!
   3 //! This is quite tricky. The main problem is time and changes -- there's no
   4 //! fixed "project" rust-analyzer is working with, "current project" is itself
   5 //! mutable state. For example, when the user edits `Cargo.toml` by adding a new
   6 //! dependency, project model changes. What's more, switching project model is
   7 //! not instantaneous -- it takes time to run `cargo metadata` and (for proc
   8 //! macros) `cargo check`.
   9 //!
  10 //! The main guiding principle here is, as elsewhere in rust-analyzer,
  11 //! robustness. We try not to assume that the project model exists or is
  12 //! correct. Instead, we try to provide a best-effort service. Even if the
  13 //! project is currently loading and we don't have a full project model, we
  14 //! still want to respond to various  requests.
  15 use std::{mem, sync::Arc};
  16
  17 use flycheck::{FlycheckConfig, FlycheckHandle};
  18 use hir::db::DefDatabase;
  19 use ide::Change;
  20 use ide_db::base_db::{
  21     CrateGraph, Env, ProcMacro, ProcMacroExpander, ProcMacroExpansionError, ProcMacroKind,
  22     ProcMacroLoadResult, SourceRoot, VfsPath,
  23 };
  24 use proc_macro_api::{MacroDylib, ProcMacroServer};
  25 use project_model::{ProjectWorkspace, WorkspaceBuildScripts};
  26 use syntax::SmolStr;
  27 use vfs::{file_set::FileSetConfig, AbsPath, AbsPathBuf, ChangeKind};
  28
  29 use crate::{
  30     config::{Config, FilesWatcher, LinkedProject},
  31     global_state::GlobalState,
  32     lsp_ext,
  33     main_loop::Task,
  34     op_queue::Cause,
  35 };
  36
  37 #[derive(Debug)]
  38 pub(crate) enum ProjectWorkspaceProgress {
  39     Begin,
  40     Report(String),
  41     End(Vec<anyhow::Result<ProjectWorkspace>>),
  42 }
  43
  44 #[derive(Debug)]
  45 pub(crate) enum BuildDataProgress {
  46     Begin,
  47     Report(String),
  48     End((Arc<Vec<ProjectWorkspace>>, Vec<anyhow::Result<WorkspaceBuildScripts>>)),
  49 }
  50
  51 impl GlobalState {
  52     pub(crate) fn is_quiescent(&self) -> bool {
  53         !(self.fetch_workspaces_queue.op_in_progress()
  54             || self.fetch_build_data_queue.op_in_progress()
  55             || self.vfs_progress_config_version < self.vfs_config_version
  56             || self.vfs_progress_n_done < self.vfs_progress_n_total)
  57     }
  58
  59     pub(crate) fn update_configuration(&mut self, config: Config) {
  60         let _p = profile::span("GlobalState::update_configuration");
  61         let old_config = mem::replace(&mut self.config, Arc::new(config));
  62         if self.config.lru_capacity() != old_config.lru_capacity() {
  63             self.analysis_host.update_lru_capacity(self.config.lru_capacity());
  64         }
  65         if self.config.linked_projects() != old_config.linked_projects() {
  66             self.fetch_workspaces_queue.request_op("linked projects changed".to_string())
  67         } else if self.config.flycheck() != old_config.flycheck() {
  68             self.reload_flycheck();
  69         }
  70
  71         if self.analysis_host.raw_database().enable_proc_attr_macros()
  72             != self.config.expand_proc_attr_macros()
  73         {
  74             self.analysis_host
  75                 .raw_database_mut()
  76                 .set_enable_proc_attr_macros(self.config.expand_proc_attr_macros());
  77         }
  78     }
  79
  80     pub(crate) fn current_status(&self) -> lsp_ext::ServerStatusParams {
  81         let mut status = lsp_ext::ServerStatusParams {
  82             health: lsp_ext::Health::Ok,
  83             quiescent: self.is_quiescent(),
  84             message: None,
  85         };
  86
  87         if self.proc_macro_changed {
  88             status.health = lsp_ext::Health::Warning;
  89             status.message =
  90                 Some("Reload required due to source changes of a procedural macro.".into())
  91         }
  92         if let Err(_) = self.fetch_build_data_error() {
  93             status.health = lsp_ext::Health::Warning;
  94             status.message =
  95                 Some("Failed to run build scripts of some packages, check the logs.".to_string());
  96         }
  97         if !self.config.cargo_autoreload()
  98             && self.is_quiescent()
  99             && self.fetch_workspaces_queue.op_requested()
 100         {
 101             status.health = lsp_ext::Health::Warning;
 102             status.message = Some("Workspace reload required".to_string())
 103         }
 104
 105         if let Err(error) = self.fetch_workspace_error() {
 106             status.health = lsp_ext::Health::Error;
 107             status.message = Some(error)
 108         }
 109         status
 110     }
 111
 112     pub(crate) fn fetch_workspaces(&mut self, cause: Cause) {
 113         tracing::info!(%cause, "will fetch workspaces");
 114
 115         self.task_pool.handle.spawn_with_sender({
 116             let linked_projects = self.config.linked_projects();
 117             let detached_files = self.config.detached_files().to_vec();
 118             let cargo_config = self.config.cargo();
 119
 120             move |sender| {
 121                 let progress = {
 122                     let sender = sender.clone();
 123                     move |msg| {
 124                         sender
 125                             .send(Task::FetchWorkspace(ProjectWorkspaceProgress::Report(msg)))
 126                             .unwrap()
 127                     }
 128                 };
 129
 130                 sender.send(Task::FetchWorkspace(ProjectWorkspaceProgress::Begin)).unwrap();
 131
 132                 let mut workspaces = linked_projects
 133                     .iter()
 134                     .map(|project| match project {
 135                         LinkedProject::ProjectManifest(manifest) => {
 136                             project_model::ProjectWorkspace::load(
 137                                 manifest.clone(),
 138                                 &cargo_config,
 139                                 &progress,
 140                             )
 141                         }
 142                         LinkedProject::InlineJsonProject(it) => {
 143                             project_model::ProjectWorkspace::load_inline(
 144                                 it.clone(),
 145                                 cargo_config.target.as_deref(),
 146                                 &cargo_config,
 147                             )
 148                         }
 149                     })
 150                     .collect::<Vec<_>>();
 151
 152                 if !detached_files.is_empty() {
 153                     workspaces
 154                         .push(project_model::ProjectWorkspace::load_detached_files(detached_files));
 155                 }
 156
 157                 tracing::info!("did fetch workspaces {:?}", workspaces);
 158                 sender
 159                     .send(Task::FetchWorkspace(ProjectWorkspaceProgress::End(workspaces)))
 160                     .unwrap();
 161             }
 162         });
 163     }
 164
 165     pub(crate) fn fetch_build_data(&mut self, cause: Cause) {
 166         tracing::info!(%cause, "will fetch build data");
 167         let workspaces = Arc::clone(&self.workspaces);
 168         let config = self.config.cargo();
 169         self.task_pool.handle.spawn_with_sender(move |sender| {
 170             sender.send(Task::FetchBuildData(BuildDataProgress::Begin)).unwrap();
 171
 172             let progress = {
 173                 let sender = sender.clone();
 174                 move |msg| {
 175                     sender.send(Task::FetchBuildData(BuildDataProgress::Report(msg))).unwrap()
 176                 }
 177             };
 178             let mut res = Vec::new();
 179             for ws in workspaces.iter() {
 180                 res.push(ws.run_build_scripts(&config, &progress));
 181             }
 182             sender.send(Task::FetchBuildData(BuildDataProgress::End((workspaces, res)))).unwrap();
 183         });
 184     }
 185
 186     pub(crate) fn switch_workspaces(&mut self, cause: Cause) {
 187         let _p = profile::span("GlobalState::switch_workspaces");
 188         tracing::info!(%cause, "will switch workspaces");
 189
 190         if let Err(error_message) = self.fetch_workspace_error() {
 191             self.show_and_log_error(error_message, None);
 192             if !self.workspaces.is_empty() {
 193                 // It only makes sense to switch to a partially broken workspace
 194                 // if we don't have any workspace at all yet.
 195                 return;
 196             }
 197         }
 198
 199         if let Err(error) = self.fetch_build_data_error() {
 200             self.show_and_log_error("failed to run build scripts".to_string(), Some(error));
 201         }
 202
 203         let workspaces = self
 204             .fetch_workspaces_queue
 205             .last_op_result()
 206             .iter()
 207             .filter_map(|res| res.as_ref().ok().cloned())
 208             .collect::<Vec<_>>();
 209
 210         fn eq_ignore_build_data<'a>(
 211             left: &'a ProjectWorkspace,
 212             right: &'a ProjectWorkspace,
 213         ) -> bool {
 214             let key = |p: &'a ProjectWorkspace| match p {
 215                 ProjectWorkspace::Cargo {
 216                     cargo,
 217                     sysroot,
 218                     rustc,
 219                     rustc_cfg,
 220                     cfg_overrides,
 221
 222                     build_scripts: _,
 223                     toolchain: _,
 224                 } => Some((cargo, sysroot, rustc, rustc_cfg, cfg_overrides)),
 225                 _ => None,
 226             };
 227             match (key(left), key(right)) {
 228                 (Some(lk), Some(rk)) => lk == rk,
 229                 _ => left == right,
 230             }
 231         }
 232
 233         let same_workspaces = workspaces.len() == self.workspaces.len()
 234             && workspaces
 235                 .iter()
 236                 .zip(self.workspaces.iter())
 237                 .all(|(l, r)| eq_ignore_build_data(l, r));
 238
 239         if same_workspaces {
 240             let (workspaces, build_scripts) = self.fetch_build_data_queue.last_op_result();
 241             if Arc::ptr_eq(workspaces, &self.workspaces) {
 242                 tracing::debug!("set build scripts to workspaces");
 243
 244                 let workspaces = workspaces
 245                     .iter()
 246                     .cloned()
 247                     .zip(build_scripts)
 248                     .map(|(mut ws, bs)| {
 249                         ws.set_build_scripts(bs.as_ref().ok().cloned().unwrap_or_default());
 250                         ws
 251                     })
 252                     .collect::<Vec<_>>();
 253
 254                 // Workspaces are the same, but we've updated build data.
 255                 self.workspaces = Arc::new(workspaces);
 256             } else {
 257                 tracing::info!("build scripts do not match the version of the active workspace");
 258                 // Current build scripts do not match the version of the active
 259                 // workspace, so there's nothing for us to update.
 260                 return;
 261             }
 262         } else {
 263             tracing::debug!("abandon build scripts for workspaces");
 264
 265             // Here, we completely changed the workspace (Cargo.toml edit), so
 266             // we don't care about build-script results, they are stale.
 267             self.workspaces = Arc::new(workspaces)
 268         }
 269
 270         if let FilesWatcher::Client = self.config.files().watcher {
 271             let registration_options = lsp_types::DidChangeWatchedFilesRegistrationOptions {
 272                 watchers: self
 273                     .workspaces
 274                     .iter()
 275                     .flat_map(|ws| ws.to_roots())
 276                     .filter(|it| it.is_local)
 277                     .flat_map(|root| {
 278                         root.include.into_iter().flat_map(|it| {
 279                             [
 280                                 format!("{}/**/*.rs", it.display()),
 281                                 format!("{}/**/Cargo.toml", it.display()),
 282                                 format!("{}/**/Cargo.lock", it.display()),
 283                             ]
 284                         })
 285                     })
 286                     .map(|glob_pattern| lsp_types::FileSystemWatcher { glob_pattern, kind: None })
 287                     .collect(),
 288             };
 289             let registration = lsp_types::Registration {
 290                 id: "workspace/didChangeWatchedFiles".to_string(),
 291                 method: "workspace/didChangeWatchedFiles".to_string(),
 292                 register_options: Some(serde_json::to_value(registration_options).unwrap()),
 293             };
 294             self.send_request::<lsp_types::request::RegisterCapability>(
 295                 lsp_types::RegistrationParams { registrations: vec![registration] },
 296                 |_, _| (),
 297             );
 298         }
 299
 300         let mut change = Change::new();
 301
 302         let files_config = self.config.files();
 303         let project_folders = ProjectFolders::new(&self.workspaces, &files_config.exclude);
 304
 305         let standalone_server_name =
 306             format!("rust-analyzer-proc-macro-srv{}", std::env::consts::EXE_SUFFIX);
 307
 308         if self.proc_macro_clients.is_empty() {
 309             if let Some((path, args)) = self.config.proc_macro_srv() {
 310                 tracing::info!("Spawning proc-macro servers");
 311                 self.proc_macro_clients = self
 312                     .workspaces
 313                     .iter()
 314                     .map(|ws| {
 315                         let mut args = args.clone();
 316                         let mut path = path.clone();
 317
 318                         if let ProjectWorkspace::Cargo { sysroot, .. }
 319                         | ProjectWorkspace::Json { sysroot, .. } = ws
 320                         {
 321                             tracing::debug!("Found a cargo workspace...");
 322                             if let Some(sysroot) = sysroot.as_ref() {
 323                                 tracing::debug!("Found a cargo workspace with a sysroot...");
 324                                 let server_path =
 325                                     sysroot.root().join("libexec").join(&standalone_server_name);
 326                                 if std::fs::metadata(&server_path).is_ok() {
 327                                     tracing::debug!(
 328                                         "And the server exists at {}",
 329                                         server_path.display()
 330                                     );
 331                                     path = server_path;
 332                                     args = vec![];
 333                                 } else {
 334                                     tracing::debug!(
 335                                         "And the server does not exist at {}",
 336                                         server_path.display()
 337                                     );
 338                                 }
 339                             }
 340                         }
 341
 342                         tracing::info!(?args, "Using proc-macro server at {}", path.display(),);
 343                         ProcMacroServer::spawn(path.clone(), args.clone()).map_err(|err| {
 344                             let error = format!(
 345                                 "Failed to run proc-macro server from path {}, error: {:?}",
 346                                 path.display(),
 347                                 err
 348                             );
 349                             tracing::error!(error);
 350                             error
 351                         })
 352                     })
 353                     .collect()
 354             };
 355         }
 356
 357         let watch = match files_config.watcher {
 358             FilesWatcher::Client => vec![],
 359             FilesWatcher::Server => project_folders.watch,
 360         };
 361         self.vfs_config_version += 1;
 362         self.loader.handle.set_config(vfs::loader::Config {
 363             load: project_folders.load,
 364             watch,
 365             version: self.vfs_config_version,
 366         });
 367
 368         // Create crate graph from all the workspaces
 369         let crate_graph = {
 370             let dummy_replacements = self.config.dummy_replacements();
 371
 372             let vfs = &mut self.vfs.write().0;
 373             let loader = &mut self.loader;
 374             let mem_docs = &self.mem_docs;
 375             let mut load = move |path: &AbsPath| {
 376                 let _p = profile::span("GlobalState::load");
 377                 let vfs_path = vfs::VfsPath::from(path.to_path_buf());
 378                 if !mem_docs.contains(&vfs_path) {
 379                     let contents = loader.handle.load_sync(path);
 380                     vfs.set_file_contents(vfs_path.clone(), contents);
 381                 }
 382                 let res = vfs.file_id(&vfs_path);
 383                 if res.is_none() {
 384                     tracing::warn!("failed to load {}", path.display())
 385                 }
 386                 res
 387             };
 388
 389             let mut crate_graph = CrateGraph::default();
 390             for (idx, ws) in self.workspaces.iter().enumerate() {
 391                 let proc_macro_client = match self.proc_macro_clients.get(idx) {
 392                     Some(res) => res.as_ref().map_err(|e| &**e),
 393                     None => Err("Proc macros are disabled"),
 394                 };
 395                 let mut load_proc_macro = move |crate_name: &str, path: &AbsPath| {
 396                     load_proc_macro(
 397                         proc_macro_client,
 398                         path,
 399                         dummy_replacements.get(crate_name).map(|v| &**v).unwrap_or_default(),
 400                     )
 401                 };
 402                 crate_graph.extend(ws.to_crate_graph(
 403                     &mut load_proc_macro,
 404                     &mut load,
 405                     &self.config.cargo(),
 406                 ));
 407             }
 408             crate_graph
 409         };
 410         change.set_crate_graph(crate_graph);
 411
 412         self.source_root_config = project_folders.source_root_config;
 413
 414         self.analysis_host.apply_change(change);
 415         self.process_changes();
 416         self.reload_flycheck();
 417         tracing::info!("did switch workspaces");
 418     }
 419
 420     fn fetch_workspace_error(&self) -> Result<(), String> {
 421         let mut buf = String::new();
 422
 423         for ws in self.fetch_workspaces_queue.last_op_result() {
 424             if let Err(err) = ws {
 425                 stdx::format_to!(buf, "rust-analyzer failed to load workspace: {:#}\n", err);
 426             }
 427         }
 428
 429         if buf.is_empty() {
 430             return Ok(());
 431         }
 432
 433         Err(buf)
 434     }
 435
 436     fn fetch_build_data_error(&self) -> Result<(), String> {
 437         let mut buf = String::new();
 438
 439         for ws in &self.fetch_build_data_queue.last_op_result().1 {
 440             match ws {
 441                 Ok(data) => match data.error() {
 442                     Some(stderr) => stdx::format_to!(buf, "{:#}\n", stderr),
 443                     _ => (),
 444                 },
 445                 // io errors
 446                 Err(err) => stdx::format_to!(buf, "{:#}\n", err),
 447             }
 448         }
 449
 450         if buf.is_empty() {
 451             Ok(())
 452         } else {
 453             Err(buf)
 454         }
 455     }
 456
 457     fn reload_flycheck(&mut self) {
 458         let _p = profile::span("GlobalState::reload_flycheck");
 459         let config = match self.config.flycheck() {
 460             Some(it) => it,
 461             None => {
 462                 self.flycheck = Vec::new();
 463                 self.diagnostics.clear_check_all();
 464                 return;
 465             }
 466         };
 467
 468         let sender = self.flycheck_sender.clone();
 469         self.flycheck = self
 470             .workspaces
 471             .iter()
 472             .enumerate()
 473             .filter_map(|(id, w)| match w {
 474                 ProjectWorkspace::Cargo { cargo, .. } => Some((id, cargo.workspace_root())),
 475                 ProjectWorkspace::Json { project, .. } => {
 476                     // Enable flychecks for json projects if a custom flycheck command was supplied
 477                     // in the workspace configuration.
 478                     match config {
 479                         FlycheckConfig::CustomCommand { .. } => Some((id, project.path())),
 480                         _ => None,
 481                     }
 482                 }
 483                 ProjectWorkspace::DetachedFiles { .. } => None,
 484             })
 485             .map(|(id, root)| {
 486                 let sender = sender.clone();
 487                 FlycheckHandle::spawn(
 488                     id,
 489                     Box::new(move |msg| sender.send(msg).unwrap()),
 490                     config.clone(),
 491                     root.to_path_buf(),
 492                 )
 493             })
 494             .collect();
 495     }
 496 }
 497
 498 #[derive(Default)]
 499 pub(crate) struct ProjectFolders {
 500     pub(crate) load: Vec<vfs::loader::Entry>,
 501     pub(crate) watch: Vec<usize>,
 502     pub(crate) source_root_config: SourceRootConfig,
 503 }
 504
 505 impl ProjectFolders {
 506     pub(crate) fn new(
 507         workspaces: &[ProjectWorkspace],
 508         global_excludes: &[AbsPathBuf],
 509     ) -> ProjectFolders {
 510         let mut res = ProjectFolders::default();
 511         let mut fsc = FileSetConfig::builder();
 512         let mut local_filesets = vec![];
 513
 514         for root in workspaces.iter().flat_map(|ws| ws.to_roots()) {
 515             let file_set_roots: Vec<VfsPath> =
 516                 root.include.iter().cloned().map(VfsPath::from).collect();
 517
 518             let entry = {
 519                 let mut dirs = vfs::loader::Directories::default();
 520                 dirs.extensions.push("rs".into());
 521                 dirs.include.extend(root.include);
 522                 dirs.exclude.extend(root.exclude);
 523                 for excl in global_excludes {
 524                     if dirs
 525                         .include
 526                         .iter()
 527                         .any(|incl| incl.starts_with(excl) || excl.starts_with(incl))
 528                     {
 529                         dirs.exclude.push(excl.clone());
 530                     }
 531                 }
 532
 533                 vfs::loader::Entry::Directories(dirs)
 534             };
 535
 536             if root.is_local {
 537                 res.watch.push(res.load.len());
 538             }
 539             res.load.push(entry);
 540
 541             if root.is_local {
 542                 local_filesets.push(fsc.len());
 543             }
 544             fsc.add_file_set(file_set_roots)
 545         }
 546
 547         let fsc = fsc.build();
 548         res.source_root_config = SourceRootConfig { fsc, local_filesets };
 549
 550         res
 551     }
 552 }
 553
 554 #[derive(Default, Debug)]
 555 pub(crate) struct SourceRootConfig {
 556     pub(crate) fsc: FileSetConfig,
 557     pub(crate) local_filesets: Vec<usize>,
 558 }
 559
 560 impl SourceRootConfig {
 561     pub(crate) fn partition(&self, vfs: &vfs::Vfs) -> Vec<SourceRoot> {
 562         let _p = profile::span("SourceRootConfig::partition");
 563         self.fsc
 564             .partition(vfs)
 565             .into_iter()
 566             .enumerate()
 567             .map(|(idx, file_set)| {
 568                 let is_local = self.local_filesets.contains(&idx);
 569                 if is_local {
 570                     SourceRoot::new_local(file_set)
 571                 } else {
 572                     SourceRoot::new_library(file_set)
 573                 }
 574             })
 575             .collect()
 576     }
 577 }
 578
 579 /// Load the proc-macros for the given lib path, replacing all expanders whose names are in `dummy_replace`
 580 /// with an identity dummy expander.
 581 pub(crate) fn load_proc_macro(
 582     server: Result<&ProcMacroServer, &str>,
 583     path: &AbsPath,
 584     dummy_replace: &[Box<str>],
 585 ) -> ProcMacroLoadResult {
 586     let res: Result<Vec<_>, String> = (|| {
 587         let dylib = MacroDylib::new(path.to_path_buf())
 588             .map_err(|io| format!("Proc-macro dylib loading failed: {io}"))?;
 589         let server = server.map_err(ToOwned::to_owned)?;
 590         let vec = server.load_dylib(dylib).map_err(|e| format!("{e}"))?;
 591         if vec.is_empty() {
 592             return Err("proc macro library returned no proc macros".to_string());
 593         }
 594         Ok(vec
 595             .into_iter()
 596             .map(|expander| expander_to_proc_macro(expander, dummy_replace))
 597             .collect())
 598     })();
 599     return match res {
 600         Ok(proc_macros) => {
 601             tracing::info!(
 602                 "Loaded proc-macros for {}: {:?}",
 603                 path.display(),
 604                 proc_macros.iter().map(|it| it.name.clone()).collect::<Vec<_>>()
 605             );
 606             Ok(proc_macros)
 607         }
 608         Err(e) => {
 609             tracing::warn!("proc-macro loading for {} failed: {e}", path.display());
 610             Err(e)
 611         }
 612     };
 613
 614     fn expander_to_proc_macro(
 615         expander: proc_macro_api::ProcMacro,
 616         dummy_replace: &[Box<str>],
 617     ) -> ProcMacro {
 618         let name = SmolStr::from(expander.name());
 619         let kind = match expander.kind() {
 620             proc_macro_api::ProcMacroKind::CustomDerive => ProcMacroKind::CustomDerive,
 621             proc_macro_api::ProcMacroKind::FuncLike => ProcMacroKind::FuncLike,
 622             proc_macro_api::ProcMacroKind::Attr => ProcMacroKind::Attr,
 623         };
 624         let expander: Arc<dyn ProcMacroExpander> =
 625             if dummy_replace.iter().any(|replace| &**replace == name) {
 626                 match kind {
 627                     ProcMacroKind::Attr => Arc::new(IdentityExpander),
 628                     _ => Arc::new(EmptyExpander),
 629                 }
 630             } else {
 631                 Arc::new(Expander(expander))
 632             };
 633         ProcMacro { name, kind, expander }
 634     }
 635
 636     #[derive(Debug)]
 637     struct Expander(proc_macro_api::ProcMacro);
 638
 639     impl ProcMacroExpander for Expander {
 640         fn expand(
 641             &self,
 642             subtree: &tt::Subtree,
 643             attrs: Option<&tt::Subtree>,
 644             env: &Env,
 645         ) -> Result<tt::Subtree, ProcMacroExpansionError> {
 646             let env = env.iter().map(|(k, v)| (k.to_string(), v.to_string())).collect();
 647             match self.0.expand(subtree, attrs, env) {
 648                 Ok(Ok(subtree)) => Ok(subtree),
 649                 Ok(Err(err)) => Err(ProcMacroExpansionError::Panic(err.0)),
 650                 Err(err) => Err(ProcMacroExpansionError::System(err.to_string())),
 651             }
 652         }
 653     }
 654
 655     /// Dummy identity expander, used for attribute proc-macros that are deliberately ignored by the user.
 656     #[derive(Debug)]
 657     struct IdentityExpander;
 658
 659     impl ProcMacroExpander for IdentityExpander {
 660         fn expand(
 661             &self,
 662             subtree: &tt::Subtree,
 663             _: Option<&tt::Subtree>,
 664             _: &Env,
 665         ) -> Result<tt::Subtree, ProcMacroExpansionError> {
 666             Ok(subtree.clone())
 667         }
 668     }
 669
 670     /// Empty expander, used for proc-macros that are deliberately ignored by the user.
 671     #[derive(Debug)]
 672     struct EmptyExpander;
 673
 674     impl ProcMacroExpander for EmptyExpander {
 675         fn expand(
 676             &self,
 677             _: &tt::Subtree,
 678             _: Option<&tt::Subtree>,
 679             _: &Env,
 680         ) -> Result<tt::Subtree, ProcMacroExpansionError> {
 681             Ok(tt::Subtree::default())
 682         }
 683     }
 684 }
 685
 686 pub(crate) fn should_refresh_for_change(path: &AbsPath, change_kind: ChangeKind) -> bool {
 687     const IMPLICIT_TARGET_FILES: &[&str] = &["build.rs", "src/main.rs", "src/lib.rs"];
 688     const IMPLICIT_TARGET_DIRS: &[&str] = &["src/bin", "examples", "tests", "benches"];
 689
 690     let file_name = match path.file_name().unwrap_or_default().to_str() {
 691         Some(it) => it,
 692         None => return false,
 693     };
 694
 695     if let "Cargo.toml" | "Cargo.lock" = file_name {
 696         return true;
 697     }
 698     if change_kind == ChangeKind::Modify {
 699         return false;
 700     }
 701
 702     // .cargo/config{.toml}
 703     if path.extension().unwrap_or_default() != "rs" {
 704         let is_cargo_config = matches!(file_name, "config.toml" | "config")
 705             && path.parent().map(|parent| parent.as_ref().ends_with(".cargo")).unwrap_or(false);
 706         return is_cargo_config;
 707     }
 708
 709     if IMPLICIT_TARGET_FILES.iter().any(|it| path.as_ref().ends_with(it)) {
 710         return true;
 711     }
 712     let parent = match path.parent() {
 713         Some(it) => it,
 714         None => return false,
 715     };
 716     if IMPLICIT_TARGET_DIRS.iter().any(|it| parent.as_ref().ends_with(it)) {
 717         return true;
 718     }
 719     if file_name == "main.rs" {
 720         let grand_parent = match parent.parent() {
 721             Some(it) => it,
 722             None => return false,
 723         };
 724         if IMPLICIT_TARGET_DIRS.iter().any(|it| grand_parent.as_ref().ends_with(it)) {
 725             return true;
 726         }
 727     }
 728     false
 729 }