feat: set-as-main for .typ/.qmd; fix compiler filter; fix ZIP import compiler

Set as main document (context menu):
- canSetRootDocId used selectedEntityIds so .typ/.qmd files couldn't be
  set as main via right-click on an unselected file.
  Now computed locally from contextMenuEntityId (same pattern as convert)
  using isValidTeXFile which already covers .typ, .qmd, .tex etc.

Compiler filter (editor settings):
- docs?.find(id) could return undefined due to ID format mismatch,
  causing all engines to show as available for non-LaTeX projects.
  Added findInTree fallback so the root doc name is always resolved.

ZIP import compiler:
- Projects created from ZIP always got defaultLatexCompiler ('quarto')
  regardless of content.
- findRootDocFileFromDirectory now also searches for .typ and .qmd root
  files after finding no .tex file.
- ProjectUploadManager now infers the compiler from the root doc
  extension and sets it on the project after import.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

services/web/app/src/Features/Project/ProjectRootDocManager.mjs

@@ -51,24 +51,20 @@ async function setRootDocAutomatically(projectId) {
 }
 
 async function findRootDocFileFromDirectory(directoryPath) {
-  const unsortedFiles = await globby(['**/*.{tex,Rtex,Rnw}'], {
+  // First try LaTeX files (look for \documentclass)
+  const unsortedTexFiles = await globby(['**/*.{tex,Rtex,Rnw,ltx}'], {
     cwd: directoryPath,
     followSymlinkedDirectories: false,
     onlyFiles: true,
     case: false,
   })
 
-  // the search order is such that we prefer files closer to the project root, then
-  // we go by file size in ascending order, because people often have a main
-  // file that just includes a bunch of other files; then we go by name, in
-  // order to be deterministic
-
-  const files = await _sortFileList(unsortedFiles, directoryPath)
-  let firstFileInRootFolder
+  const texFiles = await _sortFileList(unsortedTexFiles, directoryPath)
+  let firstTexInRootFolder
   let doc = null
 
-  while (files.length > 0 && doc == null) {
-    const file = files.shift()
+  while (texFiles.length > 0 && doc == null) {
+    const file = texFiles.shift()
     const content = await fs.promises.readFile(
       Path.join(directoryPath, file),
       'utf8'
@@ -77,18 +73,52 @@ async function findRootDocFileFromDirectory(directoryPath) {
     if (DocumentHelper.contentHasDocumentclass(normalizedContent)) {
       doc = { path: file, content: normalizedContent }
     }
-
-    if (!firstFileInRootFolder && !file.includes('/')) {
-      firstFileInRootFolder = { path: file, content: normalizedContent }
+    if (!firstTexInRootFolder && !file.includes('/')) {
+      firstTexInRootFolder = { path: file, content: normalizedContent }
     }
   }
 
-  // if no doc was found, use the first file in the root folder as the main doc
-  if (!doc && firstFileInRootFolder) {
-    doc = firstFileInRootFolder
+  if (!doc && firstTexInRootFolder) {
+    doc = firstTexInRootFolder
   }
 
-  return { path: doc?.path, content: doc?.content }
+  if (doc) return { path: doc.path, content: doc.content }
+
+  // Then try Typst files
+  const typFiles = await globby(['*.typ'], {
+    cwd: directoryPath,
+    followSymlinkedDirectories: false,
+    onlyFiles: true,
+    case: false,
+  })
+  if (typFiles.length > 0) {
+    typFiles.sort()
+    const file = typFiles[0]
+    const content = await fs.promises.readFile(
+      Path.join(directoryPath, file),
+      'utf8'
+    )
+    return { path: file, content }
+  }
+
+  // Then try Quarto/R Markdown files
+  const qmdFiles = await globby(['*.{qmd,Rmd,rmd}'], {
+    cwd: directoryPath,
+    followSymlinkedDirectories: false,
+    onlyFiles: true,
+    case: false,
+  })
+  if (qmdFiles.length > 0) {
+    qmdFiles.sort()
+    const file = qmdFiles[0]
+    const content = await fs.promises.readFile(
+      Path.join(directoryPath, file),
+      'utf8'
+    )
+    return { path: file, content }
+  }
+
+  return { path: undefined, content: undefined }
 }
 
 async function setRootDocFromName(projectId, rootDocName) {

services/web/app/src/Features/Uploads/ProjectUploadManager.mjs

@@ -14,10 +14,21 @@ import ProjectRootDocManager from '../Project/ProjectRootDocManager.mjs'
 import ProjectDetailsHandler from '../Project/ProjectDetailsHandler.mjs'
 import ProjectDeleter from '../Project/ProjectDeleter.mjs'
 import { DeletedProjectReasons } from '../Project/DeletedProjectReasons.mjs'
+import ProjectOptionsHandler from '../Project/ProjectOptionsHandler.mjs'
 import TpdsProjectFlusher from '../ThirdPartyDataStore/TpdsProjectFlusher.mjs'
 import logger from '@overleaf/logger'
 import OError from '@overleaf/o-error'
 
+const COMPILER_BY_EXTENSION = {
+  tex: 'pdflatex',
+  rtex: 'pdflatex',
+  ltx: 'pdflatex',
+  rnw: 'pdflatex',
+  typ: 'typst',
+  qmd: 'quarto',
+  rmd: 'quarto',
+}
+
 export default {
   createProjectFromZipArchive: callbackify(createProjectFromZipArchive),
   createProjectFromZipArchiveWithName: callbackify(
@@ -52,6 +63,11 @@ async function createProjectFromZipArchive(ownerId, defaultName, zipPath) {
           project._id,
           path
         )
+        const ext = path.split('.').pop()?.toLowerCase()
+        const compiler = ext ? COMPILER_BY_EXTENSION[ext] : null
+        if (compiler) {
+          await ProjectOptionsHandler.promises.setCompiler(project._id, compiler)
+        }
       }
     } catch (err) {
       // no need to wait for the cleanup here

services/web/frontend/js/features/file-tree/components/file-tree-item/file-tree-item-menu-items.tsx

@@ -14,6 +14,8 @@ import { useFileTreeMainContext } from '../../contexts/file-tree-main'
 import { findInTree } from '../../util/find-in-tree'
 import useConvertDoc from '@/features/ide-react/hooks/use-convert-doc'
 import getMeta from '@/utils/meta'
+import { isValidTeXFile } from '@/main/is-valid-tex-file'
+import { syncRootDocId } from '../../util/sync-mutation'
 
 function FileTreeItemMenuItems() {
   const { t } = useTranslation()
@@ -29,12 +31,11 @@ function FileTreeItemMenuItems() {
     startUploadingDocOrFile,
     downloadPath,
     selectedFileName,
-    canSetRootDocId,
-    setRootDocId,
   } = useFileTreeActionable()
 
-  const { project } = useProjectContext()
+  const { project, projectId, updateProject } = useProjectContext()
   const projectOwner = project?.owner?._id
+  const rootDocId = project?.rootDocId
 
   const { fileTreeData, fileTreeReadOnly } = useFileTreeData()
   const { selectedEntityIds } = useFileTreeSelectable()
@@ -42,7 +43,7 @@ function FileTreeItemMenuItems() {
   const selectedEntityId =
     selectedEntityIds.size === 1 ? Array.from(selectedEntityIds)[0] : null
 
-  // Use context-menu-target entity for convert; falls back to selection
+  // Use context-menu-target entity for convert/set-as-main; falls back to selection
   const convertEntityId = contextMenuEntityId ?? selectedEntityId
   const convertEntity = convertEntityId
     ? findInTree(fileTreeData, convertEntityId)
@@ -64,6 +65,20 @@ function FileTreeItemMenuItems() {
     isConvertableDoc &&
     convertEntityName?.endsWith('.typ')
 
+  const canShowSetAsMain =
+    !fileTreeReadOnly &&
+    isConvertableDoc &&
+    !!convertEntityId &&
+    convertEntityId !== rootDocId &&
+    !!convertEntityName &&
+    isValidTeXFile(convertEntityName)
+
+  const handleSetAsMain = useCallback(async () => {
+    if (!convertEntityId) return
+    await syncRootDocId(projectId, convertEntityId)
+    updateProject({ rootDocId: convertEntityId })
+  }, [convertEntityId, projectId, updateProject])
+
   const { convert: convertToTypst } = useConvertDoc('typst', convertEntityId)
   const { convert: convertToLatex } = useConvertDoc('latex', convertEntityId)
 
@@ -102,11 +117,11 @@ function FileTreeItemMenuItems() {
           </DropdownItem>
         </li>
       ) : null}
-      {canSetRootDocId ? (
+      {canShowSetAsMain ? (
         <>
           <DropdownDivider />
           <li role="none">
-            <DropdownItem onClick={setRootDocId}>
+            <DropdownItem onClick={handleSetAsMain}>
               {t('set_as_main_document')}
             </DropdownItem>
           </li>

services/web/frontend/js/features/settings/components/compiler-settings/compiler-setting.tsx

@@ -7,6 +7,7 @@ import { usePermissionsContext } from '@/features/ide-react/context/permissions-
 import { ProjectCompiler } from '@ol-types/project-settings'
 import { useSetCompilationSettingWithEvent } from '@/features/editor-left-menu/hooks/use-set-compilation-setting'
 import { useFileTreeData } from '@/shared/context/file-tree-data-context'
+import { findInTree } from '@/features/file-tree/util/find-in-tree'
 
 // Which compiler engines make sense for a given root-file extension. CLSI
 // dispatches the real engine from this extension (.qmd → Quarto, .typ → Typst,
@@ -34,7 +35,7 @@ export default function CompilerSetting() {
   const [compilerOptions] = useState(() => getCompilerOptions())
   const { t } = useTranslation()
   const { write } = usePermissionsContext()
-  const { docs } = useFileTreeData()
+  const { docs, fileTreeData } = useFileTreeData()
   const changeCompiler = useSetCompilationSettingWithEvent(
     'compiler',
     setCompiler
@@ -43,14 +44,21 @@ export default function CompilerSetting() {
   // Disable the engines that don't apply to the current root file's extension.
   // The currently-selected engine is always left enabled so it keeps showing.
   const options = useMemo(() => {
-    const rootDoc = rootDocId
-      ? docs?.find(doc => doc.doc.id === rootDocId)
-      : undefined
-    const extension = rootDoc?.doc.name.split('.').pop()?.toLowerCase()
+    let rootDocName: string | undefined
+    if (rootDocId) {
+      const fromDocs = docs?.find(doc => doc.doc.id === rootDocId)
+      if (fromDocs) {
+        rootDocName = fromDocs.doc.name
+      } else if (fileTreeData) {
+        // Fallback: look up directly in tree in case of ID format mismatch
+        const found = findInTree(fileTreeData, rootDocId)
+        if (found?.type === 'doc') rootDocName = found.entity.name
+      }
+    }
+    const extension = rootDocName?.split('.').pop()?.toLowerCase()
     const allowed = extension ? ENGINES_BY_EXTENSION[extension] : undefined
 
     if (!allowed) {
-      // Unknown / no root file: don't restrict anything.
       return compilerOptions
     }