Do not rely on documentclass to detect root file

See #845.

CHANGELOG.md

@@ -15,6 +15,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - Concatenate more than two lines of maximum length in build diagnostics ([#842](https://github.com/latex-lsp/texlab/pull/842))
 - Apply the correct range of references to labels when renaming ([#841](https://github.com/latex-lsp/texlab/issues/841))
+- Use `document` environment to detect root file instead of `\documentclass` ([#845](https://github.com/latex-lsp/texlab/issues/845))
 
 ## [5.1.0] - 2023-01-21
 

src/db/analysis.rs

@@ -149,6 +149,16 @@ pub struct TexAnalysis {
     pub environment_names: Vec<String>,
 }
 
+#[salsa::tracked]
+impl TexAnalysis {
+    #[salsa::tracked]
+    pub fn has_document_environment(self, db: &dyn Db) -> bool {
+        self.environment_names(db)
+            .iter()
+            .any(|name| name == "document")
+    }
+}
+
 impl TexAnalysis {
     pub(super) fn analyze(db: &dyn Db, root: &latex::SyntaxNode) -> Self {
         let mut links = Vec::new();

src/db/document.rs

@@ -175,23 +175,22 @@ impl Document {
     }
 
     #[salsa::tracked]
-    pub fn can_be_index(self, db: &dyn Db) -> bool {
+    pub fn can_be_root(self, db: &dyn Db) -> bool {
         self.parse(db).as_tex().map_or(false, |data| {
-            data.analyze(db)
-                .links(db)
-                .iter()
-                .filter(|link| link.kind(db) == TexLinkKind::Cls)
-                .any(|link| link.path(db).text(db) != "subfiles")
+            let analysis = data.analyze(db);
+            analysis.has_document_environment(db)
+                || !analysis
+                    .links(db)
+                    .iter()
+                    .filter(|link| link.kind(db) == TexLinkKind::Cls)
+                    .any(|link| link.path(db).text(db) == "subfiles")
         })
     }
 
     #[salsa::tracked]
     pub fn can_be_built(self, db: &dyn Db) -> bool {
-        self.parse(db).as_tex().map_or(false, |data| {
-            data.analyze(db)
-                .links(db)
-                .iter()
-                .any(|link| link.kind(db) == TexLinkKind::Cls)
-        })
+        self.parse(db)
+            .as_tex()
+            .map_or(false, |data| data.analyze(db).has_document_environment(db))
     }
 }

src/db/workspace.rs

@@ -67,7 +67,7 @@ impl Workspace {
         self.documents(db)
             .iter()
             .copied()
-            .filter(|&document| document.can_be_index(db))
+            .filter(|&document| document.can_be_root(db))
     }
 
     pub fn open(

src/lib.rs

@@ -23,7 +23,7 @@ pub struct Jar(
     db::LinterData,
     db::Document,
     db::Document_parse,
-    db::Document_can_be_index,
+    db::Document_can_be_root,
     db::Document_can_be_built,
     db::parse::TexDocumentData,
     db::parse::TexDocumentData_analyze,
@@ -35,6 +35,7 @@ pub struct Jar(
     db::analysis::TheoremEnvironment,
     db::analysis::GraphicsPath,
     db::analysis::TexAnalysis,
+    db::analysis::TexAnalysis_has_document_environment,
     db::MissingDependencies,
     db::hidden_dependency,
     db::source_dependency,