From 49a14c4375ce4c2c260f52db53d151742f6edeff Mon Sep 17 00:00:00 2001 From: Olivier Certner Date: Thu, 10 Nov 2022 18:57:27 +0100 Subject: [PATCH] ediff: Merges with ancestor: Fix computation of hunks and proposed merge Hunks were not computed correctly because the diff3 command was invoked with arguments in an incorrect order. The correct order is the local file first, the base (or "ancestor") second and the other file third. This erroneous behavior had two consequences. First, the output of diff3 would change, since it tries to merge chunks according to maximal matches between the second and first files, and the second and third files. Second, ediff, more precisely, `ediff-do-merge', would consequently try to merge the reverse of the changes from the base to the other file. * lisp/vc/ediff-diff.el (ediff-setup-diff-regions3): In the arguments to `ediff-exec-process', swap the other file with the ancestor (only when merging with an ancestor). (ediff-extract-diffs3): Match the hunk data for the ancestor and the other file correctly. The local variable `three-way-comp' indicates this is a merge with ancestors when it is nil. (Bug#59182) --- lisp/vc/ediff-diff.el | 35 +++++++++++++++++++++-------------- 1 file changed, 21 insertions(+), 14 deletions(-) diff --git a/lisp/vc/ediff-diff.el b/lisp/vc/ediff-diff.el index ca56a2851db..61c6dc39aa7 100644 --- a/lisp/vc/ediff-diff.el +++ b/lisp/vc/ediff-diff.el @@ -939,6 +939,9 @@ ediff-extract-diffs3 (c-prev-pt nil) (anc-prev 1) diff-list shift-A shift-B shift-C + (A-idx "1") + (B-idx (if three-way-comp "2" "3")) + (C-idx (if three-way-comp "3" "2")) ) ;; diff list contains word numbers or points, depending on word-mode @@ -976,23 +979,23 @@ ediff-extract-diffs3 (let ((agreement (buffer-substring (match-beginning 1) (match-end 1)))) ;; if the files A and B are the same and not 3way-comparison, ;; ignore the difference - (if (or three-way-comp (not (string-equal agreement "3"))) - (let* ((a-begin (car (ediff-get-diff3-group "1"))) - (a-end (nth 1 (ediff-get-diff3-group "1"))) - (b-begin (car (ediff-get-diff3-group "2"))) - (b-end (nth 1 (ediff-get-diff3-group "2"))) - (c-or-anc-begin (car (ediff-get-diff3-group "3"))) - (c-or-anc-end (nth 1 (ediff-get-diff3-group "3"))) + (if (or three-way-comp (not (string-equal agreement C-idx))) + (let* ((a-begin (car (ediff-get-diff3-group A-idx))) + (a-end (nth 1 (ediff-get-diff3-group A-idx))) + (b-begin (car (ediff-get-diff3-group B-idx))) + (b-end (nth 1 (ediff-get-diff3-group B-idx))) + (c-or-anc-begin (car (ediff-get-diff3-group C-idx))) + (c-or-anc-end (nth 1 (ediff-get-diff3-group C-idx))) (state-of-merge - (cond ((string-equal agreement "1") 'prefer-A) - ((string-equal agreement "2") 'prefer-B) + (cond ((string-equal agreement A-idx) 'prefer-A) + ((string-equal agreement B-idx) 'prefer-B) (t ediff-default-variant))) (state-of-diff-merge (if (memq state-of-merge '(default-A prefer-A)) 'B 'A)) (state-of-diff-comparison - (cond ((string-equal agreement "1") 'A) - ((string-equal agreement "2") 'B) - ((string-equal agreement "3") 'C))) + (cond ((string-equal agreement A-idx) 'A) + ((string-equal agreement B-idx) 'B) + ((string-equal agreement C-idx) 'C))) state-of-ancestor c-begin c-end a-begin-pt a-end-pt @@ -1105,8 +1108,12 @@ ediff-setup-diff-regions3 (get-buffer-create (ediff-unique-buffer-name "*ediff-diff" "*")))) (message "Computing differences ...") - (ediff-exec-process ediff-diff3-program ediff-diff-buffer 'synchronize - ediff-actual-diff3-options file-A file-B file-C) + (apply #'ediff-exec-process ediff-diff3-program ediff-diff-buffer 'synchronize + ediff-actual-diff3-options + (cons file-A (if ediff-merge-with-ancestor-job + ;; Ancestor must be the middle file + (list file-C file-B) + (list file-B file-C)))) (ediff-prepare-error-list ediff-diff3-ok-lines-regexp ediff-diff-buffer) ;;(message "Computing differences ... done") -- 2.37.3