fix(compiler): cannot bring modules more than once (attempt 2) (#3677)

Re-roll of the changes in #3605, but with more care taken to support the language server. The previous version of this PR  introduced some bugs where the LSP was using the text from disk instead of the text in the user's editor, resulting in invalid text completions and crashes. To fix this, I had to rethink the original multi-file parsing solution so that we store the latest file text from the LSP in memory.

----

Refactors how the Wing compiler handles `bring` for local Wing files in order to support more complex `bring` use cases, like allowing multiple files to `bring` the same module.

The high level implementation approach is instead of generating a single, monolithic AST, we augment the parser so that after a Wing source file is parsed, an isolated AST and a list of dependent Wing files is produced. Using this, we can write a function that parses an entire Wing program given an entrypoint, and use the `petgraph` crate to produce topological ordering of the files for type checking, and each AST is independently type checked.

Fixes #3511
Fixes #3578
Fixes #3509

## Checklist

- [x] Title matches [Winglang's style guide](https://www.winglang.io/contributing/start-here/pull_requests#how-are-pull-request-titles-formatted)
- [x] Description explains motivation and solution
- [x] Tests added (always)
- [x] Docs updated (only required for features)
- [ ] Added `pr/e2e-full` label if this feature requires end-to-end testing

*By submitting this pull request, I confirm that my contribution is made under the terms of the [Wing Cloud Contribution License](https://github.com/winglang/wing/blob/main/CONTRIBUTION_LICENSE.md)*.

apps/vscode-wing/.projenrc.ts

@@ -68,6 +68,7 @@ const project = new TypeScriptAppProject({
     "@types/ws",
     "@wingconsole/app@workspace:^",
     "@wingconsole/server@workspace:^",
+    "winglang@workspace:^",
   ],
 });
 

apps/vscode-wing/turbo.json

@@ -6,7 +6,9 @@
       "outputs": ["lib/**"]
     },
     "dev": {
-      "dependsOn": ["compile"]
+      "dependsOn": ["compile"],
+      "cache": false,
+      "persistent": true
     },
     "package": {
       "inputs": ["syntaxes/**", "resources/**"],

apps/wing/src/commands/lsp.ts

@@ -15,18 +15,17 @@ export async function lsp() {
   let wingc = await wingCompiler.load({
     imports: {
       env: {
-        send_diagnostic
+        send_diagnostic,
       },
     },
   });
   let badState = false;
 
+  const seenFiles = new Set<DocumentUri>();
+
   const raw_diagnostics: wingCompiler.WingDiagnostic[] = [];
 
-  function send_diagnostic(
-    data_ptr: number,
-    data_len: number
-  ) {
+  function send_diagnostic(data_ptr: number, data_len: number) {
     const data_buf = Buffer.from(
       (wingc.exports.memory as WebAssembly.Memory).buffer,
       data_ptr,
@@ -99,7 +98,11 @@ export async function lsp() {
     return result;
   });
 
-  async function handle_event_and_update_diagnostics(wingc_handler_name: wingCompiler.WingCompilerFunction, params: any, uri: DocumentUri) {
+  async function handle_event_and_update_diagnostics(
+    wingc_handler_name: wingCompiler.WingCompilerFunction,
+    params: any,
+    _uri: DocumentUri
+  ) {
     if (badState) {
       wingc = await wingCompiler.load({
         imports: {
@@ -114,24 +117,52 @@ export async function lsp() {
     raw_diagnostics.length = 0;
     // Call wingc handler
     callWing(wingc_handler_name, params);
-    // purposely not awaiting this, notifications are fire-and-forget
-    connection.sendDiagnostics({
-      uri,
-      diagnostics: raw_diagnostics.map((rd) => {
-        if(rd.span) {
-          return Diagnostic.create(Range.create(rd.span.start.line, rd.span.start.col, rd.span.end.line, rd.span.end.col), rd.message)
-        } else {
-          return Diagnostic.create(Range.create(0, 0, 0, 0), rd.message)
+
+    const allDiagnostics = new Map<DocumentUri, Diagnostic[]>();
+
+    // set empty list of diagnostics for files that have been seen before
+    // this way even if we don't get a diagnostic for a file, we clear out the old ones
+    for (const uri of seenFiles) {
+      allDiagnostics.set(uri, []);
+    }
+
+    for (const rd of raw_diagnostics) {
+      if (rd.span) {
+        const diagnosticUri = "file://" + rd.span.file_id;
+        const diag = Diagnostic.create(
+          Range.create(rd.span.start.line, rd.span.start.col, rd.span.end.line, rd.span.end.col),
+          rd.message
+        );
+
+        if (!allDiagnostics.has(diagnosticUri)) {
+          allDiagnostics.set(diagnosticUri, []);
+          seenFiles.add(diagnosticUri);
         }
-      })
-    });
+        allDiagnostics.get(diagnosticUri)!.push(diag);
+      } else {
+        // skip if diagnostic is not associated with any file
+      }
+    }
+
+    // purposely not awaiting these calls, notifications are fire-and-forget
+    for (const [uri, diagnostics] of allDiagnostics.entries()) {
+      connection.sendDiagnostics({ uri, diagnostics });
+    }
   }
 
   connection.onDidOpenTextDocument(async (params) => {
-    handle_event_and_update_diagnostics("wingc_on_did_open_text_document", params, params.textDocument.uri);
+    handle_event_and_update_diagnostics(
+      "wingc_on_did_open_text_document",
+      params,
+      params.textDocument.uri
+    );
   });
   connection.onDidChangeTextDocument(async (params) => {
-    handle_event_and_update_diagnostics("wingc_on_did_change_text_document", params, params.textDocument.uri);
+    handle_event_and_update_diagnostics(
+      "wingc_on_did_change_text_document",
+      params,
+      params.textDocument.uri
+    );
   });
   connection.onCompletion(async (params) => {
     return callWing("wingc_on_completion", params);

examples/tests/invalid/bring_local_self.w

@@ -1,2 +1,5 @@
 bring "./bring_local_self.w" as foo;
 // ^ error: Cannot bring a module into itself
+
+bring "./non-existent.w" as bar;
+// ^ error: Could not find Wing module "./non-existent.w"

examples/tests/invalid/cyclic_bring1.w

@@ -0,0 +1 @@
+bring "./cyclic_bring2.w" as foo;

examples/tests/invalid/cyclic_bring2.w

@@ -0,0 +1 @@
+bring "./cyclic_bring3.w" as foo;

examples/tests/invalid/cyclic_bring3.w

@@ -0,0 +1 @@
+bring "./cyclic_bring1.w" as foo;

examples/tests/valid/baz.w

@@ -0,0 +1,7 @@
+// used by bring_local_normalization.w
+
+class Baz {
+  static baz(): str {
+    return "baz";
+  }
+}

examples/tests/valid/bring_local.w

@@ -1,6 +1,7 @@
 bring "./store.w" as file1;
 bring "./subdir/subfile.w" as file2;
 bring "./subdir/empty.w" as file3;
+bring math;
 
 // classes from other files can be used
 let store = new file1.Store();

examples/tests/valid/bring_local_normalization.w

@@ -0,0 +1,13 @@
+bring "./subdir/foo.w" as foo;
+bring "./subdir/bar.w" as bar;
+bring "./baz.w" as baz;
+
+// in this app, "bar" is imported two ways (here as "./subdir/bar.w" and in foo.w as "./bar.w")
+// and "baz" is imported two ways (here as "./baz.w" and in foo.w as "../baz.w")
+// this test checks that the different imports all resolve to the same module
+
+assert(foo.Foo.foo() == "foo");
+assert(foo.Foo.bar() == "bar");
+assert(foo.Foo.baz() == "baz");
+assert(bar.Bar.bar() == "bar");
+assert(baz.Baz.baz() == "baz");

examples/tests/valid/store.w

@@ -1,3 +1,6 @@
+bring "./subdir/empty.w" as file3;
+bring math;
+
 bring cloud;
 
 class Store {

examples/tests/valid/subdir/bar.w

@@ -0,0 +1,7 @@
+// used by bring_local_normalization.w
+
+class Bar {
+  static bar(): str {
+    return "bar";
+  }
+}

examples/tests/valid/subdir/foo.w

@@ -0,0 +1,16 @@
+// used by bring_local_normalization.w
+
+bring "./bar.w" as bar;
+bring "../baz.w" as baz;
+
+class Foo {
+  static foo(): str {
+    return "foo";
+  }
+  static bar(): str {
+    return bar.Bar.bar();
+  }
+  static baz(): str {
+    return baz.Baz.baz();
+  }
+}

examples/tests/valid/subdir/subfile.w

@@ -1 +1,3 @@
+bring math;
+
 class Q {}

libs/wingc/Cargo.toml

@@ -23,6 +23,7 @@ indoc = "2.0.0"
 const_format = "0.2.30"
 duplicate = "1.0.0"
 strum = { version = "0.24", features = ["derive"] }
+petgraph = "0.6.3"
 
 [lib]
 crate-type = ["rlib", "cdylib"]

libs/wingc/src/ast.rs

@@ -421,16 +421,19 @@ pub struct Interface {
 	pub extends: Vec<UserDefinedType>,
 }
 
+#[derive(Debug)]
+pub enum BringSource {
+	BuiltinModule(Symbol),
+	JsiiModule(Symbol),
+	WingFile(Symbol),
+}
+
 #[derive(Debug)]
 pub enum StmtKind {
 	Bring {
-		module_name: Symbol, // Reference?
+		source: BringSource,
 		identifier: Option<Symbol>,
 	},
-	Module {
-		name: Symbol,
-		statements: Scope,
-	},
 	SuperConstructor {
 		arg_list: ArgList,
 	},
@@ -675,6 +678,11 @@ impl Scope {
 		assert!((*env).is_none());
 		*env = Some(new_env);
 	}
+
+	pub fn reset_env(&self) {
+		let mut env = self.env.borrow_mut();
+		*env = None;
+	}
 }
 
 #[derive(Debug)]