fix: stop type checking during runtime (#22854)

In addition to the reasons for this outlined by @nayeemrmn in #14877
(which I think are reasons alone to not do this), this simplifies things
a lot because then we don't need to implement the following:

1. Need to handle a JSR module dynamically importing a module within it.
2. Need to handle importing an export of a JSR dep then another export
dynamically loaded later.

Additionally, people should be running `deno check dynamic_import.ts`
instead of relying on this behaviour.

Landing this as a fix because it's blocking people in some scenarios and
the current behaviour is broken (I didn't even have to change any tests
to remove this, which is bad).

Closes #22852
Closes #14877
Closes #22580

cli/graph_util.rs

@@ -3,7 +3,6 @@
 use crate::args::jsr_url;
 use crate::args::CliOptions;
 use crate::args::Lockfile;
-use crate::args::TsTypeLib;
 use crate::args::DENO_DISABLE_PEDANTIC_NODE_WARNINGS;
 use crate::cache;
 use crate::cache::GlobalHttpCache;
@@ -46,7 +45,6 @@ use deno_runtime::permissions::PermissionsContainer;
 use deno_semver::package::PackageNv;
 use deno_semver::package::PackageReq;
 use import_map::ImportMapError;
-use std::collections::HashMap;
 use std::collections::HashSet;
 use std::path::PathBuf;
 use std::sync::Arc;
@@ -754,29 +752,20 @@ fn get_resolution_error_bare_specifier(
   }
 }
 
-#[derive(Debug)]
-struct GraphData {
-  graph: Arc<ModuleGraph>,
-  checked_libs: HashMap<TsTypeLib, HashSet<ModuleSpecifier>>,
-}
-
 /// Holds the `ModuleGraph` and what parts of it are type checked.
 pub struct ModuleGraphContainer {
   // Allow only one request to update the graph data at a time,
   // but allow other requests to read from it at any time even
   // while another request is updating the data.
   update_queue: Arc<TaskQueue>,
-  graph_data: Arc<RwLock<GraphData>>,
+  inner: Arc<RwLock<Arc<ModuleGraph>>>,
 }
 
 impl ModuleGraphContainer {
   pub fn new(graph_kind: GraphKind) -> Self {
     Self {
       update_queue: Default::default(),
-      graph_data: Arc::new(RwLock::new(GraphData {
+      inner: Arc::new(RwLock::new(Arc::new(ModuleGraph::new(graph_kind)))),
-        graph: Arc::new(ModuleGraph::new(graph_kind)),
-        checked_libs: Default::default(),
-      })),
     }
   }
 
@@ -787,53 +776,13 @@ impl ModuleGraphContainer {
     let permit = self.update_queue.acquire().await;
     ModuleGraphUpdatePermit {
       permit,
-      graph_data: self.graph_data.clone(),
+      inner: self.inner.clone(),
-      graph: (*self.graph_data.read().graph).clone(),
+      graph: (**self.inner.read()).clone(),
     }
   }
 
   pub fn graph(&self) -> Arc<ModuleGraph> {
-    self.graph_data.read().graph.clone()
+    self.inner.read().clone()
-  }
-
-  /// Mark `roots` and all of their dependencies as type checked under `lib`.
-  /// Assumes that all of those modules are known.
-  pub fn set_type_checked(&self, roots: &[ModuleSpecifier], lib: TsTypeLib) {
-    // It's ok to analyze and update this while the module graph itself is
-    // being updated in a permit because the module graph update is always
-    // additive and this will be a subset of the original graph
-    let graph = self.graph();
-    let entries = graph.walk(
-      roots,
-      deno_graph::WalkOptions {
-        check_js: true,
-        follow_dynamic: true,
-        follow_type_only: true,
-      },
-    );
-
-    // now update
-    let mut data = self.graph_data.write();
-    let checked_lib_set = data.checked_libs.entry(lib).or_default();
-    for (specifier, _) in entries {
-      checked_lib_set.insert(specifier.clone());
-    }
-  }
-
-  /// Check if `roots` are all marked as type checked under `lib`.
-  pub fn is_type_checked(
-    &self,
-    roots: &[ModuleSpecifier],
-    lib: TsTypeLib,
-  ) -> bool {
-    let data = self.graph_data.read();
-    match data.checked_libs.get(&lib) {
-      Some(checked_lib_set) => roots.iter().all(|r| {
-        let found = data.graph.resolve(r);
-        checked_lib_set.contains(&found)
-      }),
-      None => false,
-    }
   }
 }
 
@@ -873,7 +822,7 @@ pub fn has_graph_root_local_dependent_changed(
 /// new graph in the ModuleGraphContainer.
 pub struct ModuleGraphUpdatePermit<'a> {
   permit: TaskQueuePermit<'a>,
-  graph_data: Arc<RwLock<GraphData>>,
+  inner: Arc<RwLock<Arc<ModuleGraph>>>,
   graph: ModuleGraph,
 }
 
@@ -887,7 +836,7 @@ impl<'a> ModuleGraphUpdatePermit<'a> {
   /// and returns an Arc to the new module graph.
   pub fn commit(self) -> Arc<ModuleGraph> {
     let graph = Arc::new(self.graph);
-    self.graph_data.write().graph = graph.clone();
+    *self.inner.write() = graph.clone();
     drop(self.permit); // explicit drop for clarity
     graph
   }

cli/module_loader.rs

@@ -55,7 +55,6 @@ use deno_runtime::permissions::PermissionsContainer;
 use deno_semver::npm::NpmPackageReqReference;
 use deno_terminal::colors;
 use std::borrow::Cow;
-use std::collections::HashSet;
 use std::pin::Pin;
 use std::rc::Rc;
 use std::str;
@@ -110,11 +109,7 @@ impl ModuleLoadPreparer {
     let mut graph_update_permit =
       self.graph_container.acquire_update_permit().await;
     let graph = graph_update_permit.graph_mut();
-
+    let has_type_checked = !graph.roots.is_empty();
-    // Determine any modules that have already been emitted this session and
-    // should be skipped.
-    let reload_exclusions: HashSet<ModuleSpecifier> =
-      graph.specifiers().map(|(s, _)| s.clone()).collect();
 
     self
       .module_graph_builder
@@ -146,25 +141,24 @@ impl ModuleLoadPreparer {
     drop(_pb_clear_guard);
 
     // type check if necessary
-    if self.options.type_check_mode().is_true()
+    if self.options.type_check_mode().is_true() && !has_type_checked {
-      && !self.graph_container.is_type_checked(&roots, lib)
-    {
-      let graph = graph.segment(&roots);
       self
         .type_checker
         .check(
-          graph,
+          // todo(perf): since this is only done the first time the graph is
+          // created, we could avoid the clone of the graph here by providing
+          // the actual graph on the first run and then getting the Arc<ModuleGraph>
+          // back from the return value.
+          (*graph).clone(),
           check::CheckOptions {
             build_fast_check_graph: true,
             lib,
             log_ignored_options: false,
-            reload: self.options.reload_flag()
+            reload: self.options.reload_flag(),
-              && !roots.iter().all(|r| reload_exclusions.contains(r)),
             type_check_mode: self.options.type_check_mode(),
           },
         )
         .await?;
-      self.graph_container.set_type_checked(&roots, lib);
     }
 
     log::debug!("Prepared module load.");