Make declare module "foo" create a module

Resolves #2778

CHANGELOG.md

@@ -89,6 +89,7 @@ title: Changelog
 -   TypeDoc can now link to type alias properties, #2524.
 -   TypeDoc will now document the merged symbol type when considering globals
     declared inside `declare global`, #2774
+-   TypeDoc now converts `declare module "foo"` as a module rather than a namespace, #2778.
 -   Fixed an issue where properties were not properly marked optional in some
     cases. This primarily affected destructured parameters.
 -   Added `yaml` to the highlight languages supported by default.

src/lib/converter/symbols.ts

@@ -287,10 +287,24 @@ function convertNamespace(
     if (existingReflection?.kind === ReflectionKind.Namespace) {
         reflection = existingReflection as DeclarationReflection;
     } else {
+        let kind = ReflectionKind.Namespace;
+        let nameOverride: string | undefined;
+
+        // #2778 - always treat declare module "foo" as a module, not a namespace
+        const declareModule = symbol.declarations?.find(
+            (mod): mod is ts.ModuleDeclaration =>
+                ts.isModuleDeclaration(mod) && ts.isStringLiteral(mod.name),
+        );
+        if (declareModule) {
+            kind = ReflectionKind.Module;
+            nameOverride = declareModule.name.text;
+        }
+
         reflection = context.createDeclarationReflection(
-            ReflectionKind.Namespace,
+            kind,
             symbol,
             exportSymbol,
+            nameOverride,
         );
         context.finalizeDeclarationReflection(reflection);
     }

src/test/converter2/issues/gh2778.ts

@@ -0,0 +1,11 @@
+declare module "common" {
+    export class Base {}
+}
+declare module "foo/bar1" {
+    import { Base } from "common";
+    export class Bar1 extends Base {}
+}
+declare module "foo/bar2" {
+    import { Base } from "common";
+    export class Bar2 extends Base {}
+}

src/test/issues.c2.test.ts

@@ -1908,4 +1908,20 @@ describe("Issue Tests", () => {
             ["Extensions"],
         );
     });
+
+    it("#2778 creates modules for declare module blocks", () => {
+        const project = convert();
+        equal(
+            project.children?.map((c) => c.name),
+            ["common", "foo/bar1", "foo/bar2"],
+        );
+        equal(
+            project.children.map((c) => c.kind),
+            [
+                ReflectionKind.Module,
+                ReflectionKind.Module,
+                ReflectionKind.Module,
+            ],
+        );
+    });
 });