Adjust tree-sitter defun navigation (bug#61617)

Before this change, when you use a tree-sitter navigation function to
move to the next beginning of a thing, it jumps over the immediate
next thing and lands you at the beginning of the next-next thing.

Eg, when point is at the "|", and we evaluate
(treesit--navigate-thing pos 1 'beg), we go from

|  (thing) (thing)

to

   (thing) |(thing)

But some might expect point to go to

   |(thing) (thing)

instead, which makes sense.  Also, that's how Emacs expect defun
navigation functions to work.  The discrepancy in expectation causes
bug#61617.

In this change I made tree-sitter navigation functions to work as what
Emacs expects.  And what I described for moving to the next beginning
of thing is similarly applicable to moving to the end of previous end
of thing.

* lisp/treesit.el (treesit-beginning-of-defun)
(treesit-end-of-defun): Handle the case where defun-skipper moves
point back to where we started, by adding a retry.

(treesit--navigate-thing): Add a single condition checking for
progress to the condition form responsible for checking whether to
skip the next defun.  Namely (eq pos (funcall advance next)))).

* test/src/treesit-tests.el:
(treesit--ert-defun-navigation-nested-master)
(treesit--ert-defun-navigation-top-level-master): Change tests to
reflect the new expectation.

1 files changed, 16 insertions, 16 deletions

diff --git a/test/src/treesit-tests.el b/test/src/treesit-tests.el
index 5aa12e8aa0e..468cd221ef9 100644
--- a/test/src/treesit-tests.el
+++ b/test/src/treesit-tests.el
@@ -977,22 +977,22 @@ and \"]\"."
 
 (defvar treesit--ert-defun-navigation-nested-master
   ;; START PREV-BEG NEXT-END PREV-END NEXT-BEG
-  '((0 103 105 102 106) ; Between Beg of parent & 1st sibling.
+  '((0 103 105 102 104) ; Between Beg of parent & 1st sibling.
     (1 103 105 102 106) ; Beg of 1st sibling.
     (2 104 105 102 106) ; Inside 1st sibling.
-    (3 104 107 102 109) ; End of 1st sibling.
-    (4 104 107 102 109) ; Between 1st sibling & 2nd sibling.
-    (5 104 107 102 109) ; Beg of 2nd sibling.
+    (3 104 107 102 106) ; End of 1st sibling.
+    (4 104 107 105 106) ; Between 1st sibling & 2nd sibling.
+    (5 104 107 105 109) ; Beg of 2nd sibling.
     (6 106 107 105 109) ; Inside 2nd sibling.
     (7 106 108 105 109) ; End of 2nd sibling.
-    (8 106 108 105 109) ; Between 2nd sibling & end of parent.
-    (9 103 110 102 nil) ; End of parent.
+    (8 106 108 107 109) ; Between 2nd sibling & end of parent.
+    (9 103 110 102 109) ; End of parent.
 
-    (100 nil 102 nil 103) ; Before 1st parent.
+    (100 nil 102 nil 101) ; Before 1st parent.
     (101 nil 102 nil 103) ; Beg of 1st parent.
-    (102 101 108 nil 109) ; Between 1st & 2nd parent.
-    (103 101 108 nil 109) ; Beg of 2nd parent.
-    (110 109 nil 108 nil) ; After 3rd parent.
+    (102 101 108 102 103) ; Between 1st & 2nd parent.
+    (103 101 108 102 109) ; Beg of 2nd parent.
+    (110 109 nil 110 nil) ; After 3rd parent.
     )
   "Master of nested navigation test.
 
@@ -1000,7 +1000,7 @@ This basically says, e.g., \"start with point on marker 0, go to
 the prev-beg, now point should be at marker 103\", etc.")
 
 (defvar treesit--ert-defun-navigation-top-level-master
-  ;; START PREV-BEG NEXT-END NEXT-BEG PREV-END
+  ;; START PREV-BEG NEXT-END PREV-END NEXT-BEG
   '((0 103 108 102 109) ; Between Beg of parent & 1st sibling.
     (1 103 108 102 109) ; Beg of 1st sibling.
     (2 103 108 102 109) ; Inside 1st sibling.
@@ -1010,14 +1010,14 @@ the prev-beg, now point should be at marker 103\", etc.")
     (6 103 108 102 109) ; Inside 2nd sibling.
     (7 103 108 102 109) ; End of 2nd sibling.
     (8 103 108 102 109) ; Between 2nd sibling & end of parent.
-    (9 103 110 102 nil) ; End of parent.
+    (9 103 110 102 109) ; End of parent.
 
     ;; Top-level defuns should be identical to the nested test.
-    (100 nil 102 nil 103) ; Before 1st parent.
+    (100 nil 102 nil 101) ; Before 1st parent.
     (101 nil 102 nil 103) ; Beg of 1st parent.
-    (102 101 108 nil 109) ; Between 1st & 2nd parent.
-    (103 101 108 nil 109) ; Beg of 2nd parent.
-    (110 109 nil 108 nil) ; After 3rd parent.
+    (102 101 108 102 103) ; Between 1st & 2nd parent.
+    (103 101 108 102 109) ; Beg of 2nd parent.
+    (110 109 nil 110 nil) ; After 3rd parent.
     )
   "Master of top-level navigation test.")