Merge branch 'cc/reset-more'

* cc/reset-more:
  t7111: check that reset options work as described in the tables
  Documentation: reset: add some missing tables
  Fix bit assignment for CE_CONFLICTED
  "reset --merge": fix unmerged case
  reset: use "unpack_trees()" directly instead of "git read-tree"
  reset: add a few tests for "git reset --merge"
  Documentation: reset: add some tables to describe the different options
  reset: improve mixed reset error message when in a bare repo

1 files changed, 89 insertions, 0 deletions

diff --git a/Documentation/git-reset.txt b/Documentation/git-reset.txt
index 9df6de2e7d..c7aa444317 100644
--- a/Documentation/git-reset.txt
+++ b/Documentation/git-reset.txt
@@ -68,6 +68,95 @@ linkgit:git-add[1]).
 <commit>::
 	Commit to make the current HEAD. If not given defaults to HEAD.
 
+DISCUSSION
+----------
+
+The tables below show what happens when running:
+
+----------
+git reset --option target
+----------
+
+to reset the HEAD to another commit (`target`) with the different
+reset options depending on the state of the files.
+
+In these tables, A, B, C and D are some different states of a
+file. For example, the first line of the first table means that if a
+file is in state A in the working tree, in state B in the index, in
+state C in HEAD and in state D in the target, then "git reset --soft
+target" will put the file in state A in the working tree, in state B
+in the index and in state D in HEAD.
+
+      working index HEAD target         working index HEAD
+      ----------------------------------------------------
+       A       B     C    D     --soft   A       B     D
+				--mixed  A       D     D
+				--hard   D       D     D
+				--merge (disallowed)
+
+      working index HEAD target         working index HEAD
+      ----------------------------------------------------
+       A       B     C    C     --soft   A       B     C
+				--mixed  A       C     C
+				--hard   C       C     C
+				--merge (disallowed)
+
+      working index HEAD target         working index HEAD
+      ----------------------------------------------------
+       B       B     C    D     --soft   B       B     D
+				--mixed  B       D     D
+				--hard   D       D     D
+				--merge  D       D     D
+
+      working index HEAD target         working index HEAD
+      ----------------------------------------------------
+       B       B     C    C     --soft   B       B     C
+				--mixed  B       C     C
+				--hard   C       C     C
+				--merge  C       C     C
+
+      working index HEAD target         working index HEAD
+      ----------------------------------------------------
+       B       C     C    D     --soft   B       C     D
+				--mixed  B       D     D
+				--hard   D       D     D
+				--merge (disallowed)
+
+      working index HEAD target         working index HEAD
+      ----------------------------------------------------
+       B       C     C    C     --soft   B       C     C
+				--mixed  B       C     C
+				--hard   C       C     C
+				--merge  B       C     C
+
+"reset --merge" is meant to be used when resetting out of a conflicted
+merge. Any mergy operation guarantees that the work tree file that is
+involved in the merge does not have local change wrt the index before
+it starts, and that it writes the result out to the work tree. So if
+we see some difference between the index and the target and also
+between the index and the work tree, then it means that we are not
+resetting out from a state that a mergy operation left after failing
+with a conflict. That is why we disallow --merge option in this case.
+
+The following tables show what happens when there are unmerged
+entries:
+
+      working index HEAD target         working index HEAD
+      ----------------------------------------------------
+       X       U     A    B     --soft  (disallowed)
+				--mixed  X       B     B
+				--hard   B       B     B
+				--merge  B       B     B
+
+      working index HEAD target         working index HEAD
+      ----------------------------------------------------
+       X       U     A    A     --soft  (disallowed)
+				--mixed  X       A     A
+				--hard   A       A     A
+				--merge  A       A     A
+
+X means any state and U means an unmerged index.
+
 Examples
 --------