[nongnu] elpa/git-commit f9a15cb349: magit-discard-files: Account for 'renamed on both sides' conflicts

[ELPA Syncer]

branch: elpa/git-commit
commit f9a15cb349b24ce705cae3dde646a1e027dc54d5
Author: Kyle Meyer <kyle@kyleam.com>
Commit: Kyle Meyer <kyle@kyleam.com>

    magit-discard-files: Account for 'renamed on both sides' conflicts
    
    Merging two lines that both renamed a file leads to a conflict like
    this:
    
        DD f
        AU f-rename
        UA f-rename-side
    
    In the status buffer, that shows up as three staged entries:
    
        Staged changes (3)
        unmerged   f (both deleted)
        unmerged   f-rename (added by us)
        unmerged   f-rename-side (added by them)
    
    For conflicts in the staged section, calling magit-discard to trigger
    magit-discard-files--resolve/magit-checkout-stage is useful for
    letting the caller choose a side's variant.  However, that doesn't
    work for the entries above:
    
      * On the first entry, magit-discard-files--delete is called rather
        than magit-discard-files--resolve/magit-checkout-stage, and it
        fails trying to delete a working tree file that isn't there.
    
      * On the second and third entries, calling magit-discard does go
        down the magit-discard-files--resolve/magit-checkout-stage path.
        That works as expected when choosing the side with the file in its
        tree (e.g., choosing "ours" for f-rename above).  However,
        choosing the other side leads to the 'git checkout --ours/theirs'
        call failing because the file doesn't exist on that side.
    
    Fix magit-discard on the first entry by sending DD entries to
    magit-discard-files--resolve rather than magit-discard-files--delete.
    Asking the caller to choose a side is a bit odd because either side is
    equivalent, but it's probably an uncommon enough case that it's not
    worth adding dedicated handling for it.
    
    Fix magit-discard on the second and third entries by teaching
    magit-checkout-stage go down the 'git rm' path if it sees UA/AU for
    the side the does not have the file in its tree.
    
    Fixes #4225.
---
 docs/RelNotes/3.4.0.org | 3 +++
 lisp/magit-apply.el     | 3 ++-
 lisp/magit-merge.el     | 4 +++-
 3 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/docs/RelNotes/3.4.0.org b/docs/RelNotes/3.4.0.org
index a46e266fc4..cc0c0aaa19 100644
--- a/docs/RelNotes/3.4.0.org
+++ b/docs/RelNotes/3.4.0.org
@@ -45,3 +45,6 @@
 
 - For Helm users, calling ~magit-stash-drop~ on the "Stashes" section
   has been broken since v3.0.0.  #4571
+
+- ~magit-discard~ didn't properly handle conflicts resulting from a
+  file being renamed on both sides.  #4225
diff --git a/lisp/magit-apply.el b/lisp/magit-apply.el
index 3edae33c08..2ca43e0aef 100644
--- a/lisp/magit-apply.el
+++ b/lisp/magit-apply.el
@@ -546,7 +546,8 @@ of a side, then keep that side without prompting."
           (`(?Z) (dolist (f (magit-untracked-files nil file))
                    (push f delete)))
           ((or `(?Z ?? ??) `(?Z ?! ?!)) (push file delete))
-          ((or `(?Z ?D ? ) `(,_ ?D ?D)) (push file delete))
+          (`(?Z ?D ? )                  (push file delete))
+          (`(,_ ?D ?D)                  (push file resolve))
           ((or `(,_ ?U ,_) `(,_ ,_ ?U)) (push file resolve))
           (`(,_ ?A ?A)                  (push file resolve))
           (`(?X ?M ,(or ?  ?M ?D)) (push section discard))
diff --git a/lisp/magit-merge.el b/lisp/magit-merge.el
index 470cac96a1..d153c2755a 100644
--- a/lisp/magit-merge.el
+++ b/lisp/magit-merge.el
@@ -255,7 +255,9 @@ then also remove the respective remote branch."
             (user-error "Quit")))))
   (pcase (cons arg (cddr (car (magit-file-status file))))
     ((or `("--ours"   ?D ,_)
-         `("--theirs" ,_ ?D))
+         `("--ours"   ?U ?A)
+         `("--theirs" ,_ ?D)
+         `("--theirs" ?A ?U))
      (magit-run-git "rm" "--" file))
     (_ (if (equal arg "--merge")
            ;; This fails if the file was deleted on one