[elpa] externals/auctex a27850f 10/30: Fix previous commit and add new test

[Tassilo Horn]

branch: externals/auctex
commit a27850faedf2a9c0871a558353a8f8f42597794c
Author: Ikumi Keita <ikumi@ikumi.que.jp>
Commit: Ikumi Keita <ikumi@ikumi.que.jp>

    Fix previous commit and add new test
    
    * font-latex.el (font-latex-extend-region-backwards-quotation): Move
    the point back to the correct position when the inner loop search
    fails.
    * tests/latex/font-latex-test.el
    (font-latex-extend-region-backwards-quotation): New test.
---
 font-latex.el                  | 67 ++++++++++++++++++++++++------------------
 tests/latex/font-latex-test.el | 40 +++++++++++++++++++++++++
 2 files changed, 78 insertions(+), 29 deletions(-)

diff --git a/font-latex.el b/font-latex.el
index 09a6feb..6ce901f 100644
--- a/font-latex.el
+++ b/font-latex.el
@@ -2050,12 +2050,13 @@ set to french, and >>german<< (and 8-bit) are used if 
set to german."
   "Extend region backwards for quotations."
   (when font-latex-quotes
     (font-latex-update-quote-list)
-    (let ((regexp-end (regexp-opt (mapcar 'cadr font-latex-quote-list) t)))
+    (let ((regexp-end (regexp-opt (mapcar #'cadr font-latex-quote-list) t)))
       (save-excursion
        (goto-char font-lock-end)
        (catch 'extend
          (while (re-search-backward regexp-end font-lock-beg t)
-           (let ((closing-quote (match-string 0))
+           (let ((found-end (match-beginning 0))
+                 (closing-quote (match-string-no-properties 0))
                  (nest-count 0)
                  (point-of-surrender (- font-lock-beg
                                          font-latex-multiline-boundary))
@@ -2066,33 +2067,41 @@ set to french, and >>german<< (and 8-bit) are used if 
set to german."
                    (setq opening-quote (car elt))
                    (throw 'found nil))))
              ;; Find opening quote taking nested quotes into account.
-             (while (and (re-search-backward (concat opening-quote "\\|"
-                                                     closing-quote)
-                                             point-of-surrender t)
-                         ;; Found quotes before point-of-surrender.
-                         (cond ((string= (match-string 0) closing-quote)
-                                ;; Encountered another closing quote.
-                                ;; Increase nest-count and continue
-                                ;; the inner loop.
-                                (setq nest-count (1+ nest-count)))
-                               ;; Found an opening quote.
-                               ((/= nest-count 0)
-                                ;; If in nest, decrease nest-count
-                                ;; and continue the inner loop.
-                                (setq nest-count (1- nest-count)))
-                               ;; Else we arrived at the opening quote
-                               ;; matching with the closing quote found
-                               ;; in the outer loop.
-                               ((< (point) font-lock-beg)
-                                ;; If that opening quote locates
-                                ;; before `font-lock-beg', break the
-                                ;; outer loop and extend the region.
-                                (setq font-lock-beg (point))
-                                (throw 'extend t))
-                               (t
-                                ;; Else terminate the inner loop and
-                                ;; continue the outer loop.
-                                nil)))))))))))
+             (while (if (re-search-backward (concat opening-quote "\\|"
+                                                    closing-quote)
+                                            point-of-surrender 'move)
+                        ;; Found quotes before point-of-surrender.
+                        (cond ((string= (match-string-no-properties 0)
+                                        closing-quote)
+                               ;; Encountered another closing quote.
+                               ;; Increase nest-count and continue
+                               ;; the inner loop.
+                               (setq nest-count (1+ nest-count)))
+                              ;; Found an opening quote.
+                              ((/= nest-count 0)
+                               ;; If in nest, decrease nest-count
+                               ;; and continue the inner loop.
+                               (setq nest-count (1- nest-count)))
+                              ;; Else we arrived at the opening quote
+                              ;; matching with the closing quote found
+                              ;; in the outer loop.
+                              ((< (point) font-lock-beg)
+                               ;; If that opening quote locates
+                               ;; before `font-lock-beg', break the
+                               ;; outer loop and extend the region.
+                               (setq font-lock-beg (point))
+                               (throw 'extend t))
+                              (t
+                               ;; Else terminate the inner loop and
+                               ;; continue the outer loop.
+                               nil))
+                      ;; Didn't find quotes before
+                      ;; point-of-surrender.
+                      ;; Go back just before the closing quote,
+                      ;; terminate the inner loop and
+                      ;; continue the outer loop.
+                      (goto-char found-end)
+                      nil)))))))))
 
 (defun font-latex-match-script (limit)
   "Match subscript and superscript patterns up to LIMIT."
diff --git a/tests/latex/font-latex-test.el b/tests/latex/font-latex-test.el
index c45a7b5..a869fe4 100644
--- a/tests/latex/font-latex-test.el
+++ b/tests/latex/font-latex-test.el
@@ -41,4 +41,44 @@ $a$")
              (setq font-latex--updated-region-end (point-max))
              (font-latex-match-dollar-math (point-max))))))
 
+(ert-deftest font-latex-extend-region-backwards-quotation ()
+  "Test f-l-e-r-b-q doesn't extend region too eagerly."
+  (with-temp-buffer
+    (let ((TeX-install-font-lock 'font-latex-setup)
+         (font-latex-quotes 'french)
+         font-lock-beg font-lock-end)
+      (LaTeX-mode)
+
+      ;; Test 1: Double prime in math expression doesn't cause region
+      ;; extension.
+      (setq font-lock-beg (point))
+      (insert "$f''(x)=x^{3}$")
+      (setq font-lock-end (point))
+      (should-not (font-latex-extend-region-backwards-quotation))
+
+      (erase-buffer)
+      (insert "abc ``def ghi'' jkl ")
+      (setq font-lock-beg (point))
+      (insert "$f''(x)=x^{3}$")
+      (setq font-lock-end (point))
+      (should-not (font-latex-extend-region-backwards-quotation))
+
+      ;; Test 2: open-close pair before '' in math expression is
+      ;; picked up.
+      (erase-buffer)
+      (insert "abc ``def ")
+      (setq font-lock-beg (point))
+      (insert "ghi'' jkl $f''(x)=x^{3}$")
+      (setq font-lock-end (point))
+      (should (font-latex-extend-region-backwards-quotation))
+      (should (= font-lock-beg 5))
+
+      (erase-buffer)
+      (insert "abc <<def ")
+      (setq font-lock-beg (point))
+      (insert "ghi>> jkl $f''(x)=x^{3}$")
+      (setq font-lock-end (point))
+      (should (font-latex-extend-region-backwards-quotation))
+      (should (= font-lock-beg 5)))))
+
 ;;; font-latex-test.el ends here