org-export: Fix expansion of babel calls in included files

* contrib/lisp/org-export.el (org-export-as):
  `org-current-export-file' should refer to current, temporary, buffer
  containing included contents, not to original buffer with include
  keywords.
(org-export-with-current-buffer-copy): Buffer copy must contain the
whole buffer, possibly narrowed to a proper part, not only the
narrowed part.
* testing/lisp/test-org-export.el: Tweak tests.

contrib/lisp/org-export.el

@@ -2564,9 +2564,7 @@ Return code as a string."
 	     ;;    Instead, a temporary copy is created, where include
 	     ;;    keywords and macros are expanded and code blocks
 	     ;;    are evaluated.
-	     (tree (let ((buf (or (buffer-file-name (buffer-base-buffer))
-				  (current-buffer))))
-		     (org-export-with-current-buffer-copy
+	     (tree (org-export-with-current-buffer-copy
 		    (unless noexpand
 		      (org-export-expand-include-keyword)
 		      ;; Update radio targets since keyword
@@ -2579,7 +2577,7 @@ Return code as a string."
 		      ;; removed, modify
 		      ;; `org-export-blocks-preprocess' so it
 		      ;; accepts the value as an argument instead.
-			(let ((org-current-export-file buf))
+		      (let ((org-current-export-file (current-buffer)))
 			(org-export-blocks-preprocess)))
 		    (goto-char (point-min))
 		    ;; Run hook
@@ -2588,7 +2586,7 @@ Return code as a string."
 		    (run-hook-with-args
 		     'org-export-before-parsing-hook backend)
 		    ;; Eventually parse buffer.
-		      (org-element-parse-buffer nil visible-only)))))
+		    (org-element-parse-buffer nil visible-only))))
 	;; 3. Call parse-tree filters to get the final tree.
 	(setq tree
 	      (org-export-filter-apply-functions
@@ -2717,28 +2715,25 @@ The copy preserves local variables and visibility of the original
 buffer.
 
 Point is at buffer's beginning when BODY is applied."
-  (org-with-gensyms (original-buffer offset buffer-string overlays)
-    `(let ((,original-buffer (current-buffer))
-	   (,offset (1- (point-min)))
-	   (,buffer-string (buffer-string))
-	   (,overlays (mapcar
-		       'copy-overlay (overlays-in (point-min) (point-max)))))
+  (declare (debug (body)))
+  (org-with-gensyms (original-buffer offset buffer-string overlays region)
+    `(let* ((,original-buffer (current-buffer))
+	    (,region (list (point-min) (point-max)))
+	    (,buffer-string (org-with-wide-buffer (buffer-string)))
+	    (,overlays (mapcar 'copy-overlay (apply 'overlays-in ,region))))
        (with-temp-buffer
 	 (let ((buffer-invisibility-spec nil))
 	   (org-clone-local-variables
 	    ,original-buffer
 	    "^\\(org-\\|orgtbl-\\|major-mode$\\|outline-\\(regexp\\|level\\)$\\)")
 	   (insert ,buffer-string)
+	   (apply 'narrow-to-region ,region)
 	   (mapc (lambda (ov)
 		   (move-overlay
-		    ov
-		    (- (overlay-start ov) ,offset)
-		    (- (overlay-end ov) ,offset)
-		    (current-buffer)))
+		    ov (overlay-start ov) (overlay-end ov) (current-buffer)))
 		 ,overlays)
 	   (goto-char (point-min))
 	   (progn ,@body))))))
-(def-edebug-spec org-export-with-current-buffer-copy (body))
 
 (defun org-export-expand-macro (info)
   "Expand every macro in buffer.

testing/lisp/test-org-export.el

@@ -368,6 +368,8 @@ text
       (goto-char (point-at-eol))
       (should (equal (org-export-as 'test) "text\n"))))
   ;; Subtree with a code block calling another block outside.
+  (should
+   (equal ": 3\n"
 	  (org-test-with-temp-text "
 * Head1
 #+BEGIN_SRC emacs-lisp :noweb yes :exports results
@@ -380,7 +382,7 @@ text
 #+END_SRC"
 	    (org-test-with-backend test
 	      (forward-line 1)
-      (should (equal (org-export-as 'test 'subtree) ": 3\n")))))
+	      (org-export-as 'test 'subtree))))))
 
 (ert-deftest test-org-export/expand-include ()
   "Test file inclusion in an Org buffer."