Merge branch 'kb/full-history-compute-treesame-carefully-2'

diff --git a/Documentation/rev-list-options.txt b/Documentation/rev-list-options.txt
index f41e86545bed15b825515eb6b4e404b031c8892b..b462f17f62d4c0066b1178b405b011963643cdd9 100644 (file)
--- a/Documentation/rev-list-options.txt
+++ b/Documentation/rev-list-options.txt
@@ -342,13 +342,13 @@ In the following, we will always refer to the same example history to
 illustrate the differences between simplification settings.  We assume
 that you are filtering for a file `foo` in this commit graph:
 -----------------------------------------------------------------------
-         .-A---M---N---O---P
-        /     /   /   /   /
-       I     B   C   D   E
-        \   /   /   /   /
-         `-------------'
+         .-A---M---N---O---P---Q
+        /     /   /   /   /   /
+       I     B   C   D   E   Y
+        \   /   /   /   /   /
+         `-------------'   X
 -----------------------------------------------------------------------
-The horizontal line of history A---P is taken to be the first parent of
+The horizontal line of history A---Q is taken to be the first parent of
 each merge.  The commits are:
 
 * `I` is the initial commit, in which `foo` exists with contents
@@ -369,6 +369,10 @@ each merge.  The commits are:
 * `E` changes `quux` to "xyzzy", and its merge `P` combines the
   strings to "quux xyzzy".  `P` is TREESAME to `O`, but not to `E`.
 
+* `X` is an indpendent root commit that added a new file `side`, and `Y`
+  modified it. `Y` is TREESAME to `X`. Its merge `Q` added `side` to `P`, and
+  `Q` is TREESAME to `P`, but not to `Y`.
+
 'rev-list' walks backwards through history, including or excluding
 commits based on whether '\--full-history' and/or parent rewriting
 (via '\--parents' or '\--children') are used.  The following settings
@@ -409,7 +413,7 @@ parent lines.
        the example, we get
 +
 -----------------------------------------------------------------------
-       I  A  B  N  D  O  P
+       I  A  B  N  D  O  P  Q
 -----------------------------------------------------------------------
 +
 `M` was excluded because it is TREESAME to both parents.  `E`,
@@ -430,7 +434,7 @@ Along each parent, prune away commits that are not included
 themselves.  This results in
 +
 -----------------------------------------------------------------------
-         .-A---M---N---O---P
+         .-A---M---N---O---P---Q
         /     /   /   /   /
        I     B   /   D   /
         \   /   /   /   /
@@ -440,7 +444,7 @@ themselves.  This results in
 Compare to '\--full-history' without rewriting above.  Note that `E`
 was pruned away because it is TREESAME, but the parent list of P was
 rewritten to contain `E`'s parent `I`.  The same happened for `C` and
-`N`.
+`N`, and `X`, `Y` and `Q`.
 
 In addition to the above settings, you can change whether TREESAME
 affects inclusion:
@@ -470,9 +474,9 @@ history according to the following rules:
 * Set `C'` to `C`.
 +
 * Replace each parent `P` of `C'` with its simplification `P'`.  In
-  the process, drop parents that are ancestors of other parents, and
-  remove duplicates, but take care to never drop all parents that
-  we are TREESAME to.
+  the process, drop parents that are ancestors of other parents or that are
+  root commits TREESAME to an empty tree, and remove duplicates, but take care
+  to never drop all parents that we are TREESAME to.
 +
 * If after this parent rewriting, `C'` is a root or merge commit (has
   zero or >1 parents), a boundary commit, or !TREESAME, it remains.
@@ -490,7 +494,7 @@ The effect of this is best shown by way of comparing to
          `---------'
 -----------------------------------------------------------------------
 +
-Note the major differences in `N` and `P` over '--full-history':
+Note the major differences in `N`, `P` and `Q` over '--full-history':
 +
 --
 * `N`'s parent list had `I` removed, because it is an ancestor of the
@@ -498,6 +502,10 @@ Note the major differences in `N` and `P` over '--full-history':
 +
 * `P`'s parent list similarly had `I` removed.  `P` was then
   removed completely, because it had one parent and is TREESAME.
++
+* `Q`'s parent list had `Y` simplified to `X`. `X` was then removed, because it
+  was a TREESAME root. `Q` was then removed completely, because it had one
+  parent and is TREESAME.
 --
 
 Finally, there is a fifth simplification mode available: