[Fix bbatsov#952] Exclude out-of-project VCS submodules

projectile.el

@@ -912,15 +912,9 @@ Files are returned as relative paths to the project root."
      (t ""))))
 
 (defun projectile-get-all-sub-projects (project)
-  "Get all sub-projects for a given projects.
+  "Get all sub-projects for a given project.
 PROJECT is base directory to start search recursively."
-  (let* ((default-directory project)
-         ;; search for sub-projects under current project `project'
-         (submodules (mapcar
-                      (lambda (s)
-                        (file-name-as-directory (expand-file-name s default-directory)))
-                      (projectile-files-via-ext-command (projectile-get-sub-projects-command)))))
-
+  (let ((submodules (projectile-get-immediate-sub-projects project)))
     (cond
      ((null submodules)
       nil)
@@ -930,6 +924,27 @@ PROJECT is base directory to start search recursively."
                          (mapcar (lambda (s)
                                    (projectile-get-all-sub-projects s)) submodules)))))))
 
+(defun projectile-get-immediate-sub-projects (project)
+  "Get immediate sub-projects for a given project without recursing.
+PROJECT is the VCS root from which to start searching, and should end
+with an appropriate path delimiter, such as '/' or a '\\'."
+  (let* ((default-directory project)
+         ;; search for sub-projects under current project `project'
+         (submodules (mapcar
+                      (lambda (s)
+                        (file-name-as-directory (expand-file-name s default-directory)))
+                      (projectile-files-via-ext-command (projectile-get-sub-projects-command))))
+         (project-child-folder-regex
+          (concat "\\`"
+                  (regexp-quote project))))
+
+    ;; If project root is inside of an VCS folder, but not actually an
+    ;; VCS root itself, external paths will leak in. Let's remove them
+    (-filter (lambda (path)
+               (string-match-p project-child-folder-regex
+                               path))
+             submodules)))
+
 (defun projectile-get-sub-projects-files ()
   "Get files from sub-projects recursively."
   (-flatten

test/projectile-test.el

@@ -636,6 +636,31 @@
                          (projectile-find-matching-file
                           "spec/models/food/sea_spec.rb"))))))))
 
+(ert-deftest projectile-test-exclude-out-of-project-submodules ()
+  (projectile-test-with-files
+      (;; VSC root is here
+       "project/"
+       "project/.git/"
+       "project/.gitmodules"
+       ;; Current project root is here:
+       "project/web-ui/"
+       "project/web-ui/.projectile"
+       ;; VCS git submodule will return the following submodules,
+       ;; relative to current project root, 'project/web-ui/':
+       "project/web-ui/vendor/client-submodule/"
+       "project/server/vendor/server-submodule/")
+    (let ((project (file-truename (expand-file-name "project/web-ui"))))
+      (noflet ((projectile-files-via-ext-command
+                (arg) (when (string= default-directory project)
+                        '("vendor/client-submodule"
+                          "../server/vendor/server-submodule")))
+               (projectile-project-root
+                () (file-truename (expand-file-name web-ui-path))))
+
+        ;; assert that it only returns the submodule 'project/web-ui/vendor/client-submodule/'
+        (should (equal (list (expand-file-name "vendor/client-submodule/" project))
+                       (projectile-get-all-sub-projects project)))))))
+
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