Include intermediate directories in projectile-find-dir (#1596)

projectile-project-dirs previously only returned directories that
directly contain files, missing intermediate directories that contain
only subdirectories (e.g. src/ when it only has src/ComponentA/).

Fix by walking each file path's ancestor directories up to the project
root, so all intermediate directories are included.

Author: bbatsov

CHANGELOG.md

@@ -10,6 +10,7 @@
 
 * [#1748](https://github.com/bbatsov/projectile/issues/1748): Fix `projectile-replace` falling back to the legacy Emacs 25/26 code path on Emacs 27+ because `fileloop` was not loaded.
 * [#1741](https://github.com/bbatsov/projectile/issues/1741): Fix `projectile-replace` treating the search string as a regexp instead of a literal string on Emacs 27+.
+* [#1596](https://github.com/bbatsov/projectile/issues/1596): `projectile-find-dir` now includes intermediate directories that contain only subdirectories (e.g. `src/` when it only has `src/ComponentA/`, `src/ComponentB/`).
 * [#1551](https://github.com/bbatsov/projectile/issues/1551): Don't add nonexistent files to the project cache (e.g. when visiting a new file with `find-file` and then abandoning the buffer).
 * [#1554](https://github.com/bbatsov/projectile/issues/1554): Fix `projectile-files-with-string` failing on special characters when using `grep` or `git-grep` by adding the `-F` (fixed-string) flag.
 * [#1897](https://github.com/bbatsov/projectile/issues/1897): Filter deleted-but-unstaged files from `git ls-files` output in alien/hybrid indexing (when `fd` is not used).

projectile.el

@@ -2281,8 +2281,19 @@ project-root for every file."
   "Return a list of dirs for PROJECT."
   (delete-dups
    (delq nil
-         (mapcar #'file-name-directory
-                 (projectile-project-files project)))))
+         (cl-mapcan #'projectile--directory-ancestors
+                    (projectile-project-files project)))))
+
+(defun projectile--directory-ancestors (path)
+  "Return a list of the directory of PATH and all its ancestor directories.
+For example, \"src/foo/bar.el\" returns (\"src/foo/\" \"src/\")."
+  (let ((dir (file-name-directory path))
+        result)
+    (while (and dir (not (equal dir "")))
+      (push dir result)
+      (let ((parent (file-name-directory (directory-file-name dir))))
+        (setq dir (unless (equal parent dir) parent))))
+    result))
 
 (defun projectile-current-project-dirs ()
   "Return a list of dirs for the current project."

test/projectile-test.el

@@ -554,6 +554,20 @@ Just delegates OPERATION and ARGS for all operations except for`shell-command`'.
           (expect files :to-contain "existing.txt")
           (expect files :not :to-contain "deleted.txt")))))))
 
+(describe "projectile-project-dirs"
+  (it "includes intermediate directories that contain only subdirectories"
+    (spy-on 'projectile-project-files
+            :and-return-value '("src/ComponentA/a.cc"
+                                "src/ComponentB/b.cc"
+                                "config/config_file"))
+    (let ((dirs (projectile-project-dirs "/project/")))
+      ;; Leaf directories
+      (expect dirs :to-contain "src/ComponentA/")
+      (expect dirs :to-contain "src/ComponentB/")
+      (expect dirs :to-contain "config/")
+      ;; Intermediate directory (only has subdirectories, no direct files)
+      (expect dirs :to-contain "src/"))))
+
 (describe "projectile-index-directory"
   (it "skips unreadable directories"
     (unless (eq system-type 'windows-nt)