@ -581,12 +581,12 @@ option does. Applied to the 'D..M' range, it results in:
@@ -581,12 +581,12 @@ option does. Applied to the 'D..M' range, it results in:
Before discussing another option, `--show-pulls`, we need to
create a new example history.
+
A common problem users face when looking at simplified history is that a
commit they know changed a file somehow does not appear in the file's
simplified history. Let's demonstrate a new example and show how options
such as `--full-history` and `--simplify-merges` works in that case:
@ -595,7 +595,7 @@ such as `--full-history` and `--simplify-merges` works in that case:
@@ -595,7 +595,7 @@ such as `--full-history` and `--simplify-merges` works in that case:
For this example, suppose `I` created `file.txt` which was modified by
`A`, `B`, and `X` in different ways. The single-parent commits `C`, `Z`,
and `Y` do not change `file.txt`. The merge commit `M` was created by
@ -607,19 +607,19 @@ the contents of `file.txt` at `X`. Hence, `R` is TREESAME to `X` but not
@@ -607,19 +607,19 @@ the contents of `file.txt` at `X`. Hence, `R` is TREESAME to `X` but not
contents of `file.txt` at `R`, so `N` is TREESAME to `R` but not `C`.
The merge commits `O` and `P` are TREESAME to their first parents, but
not to their second parents, `Z` and `Y` respectively.
+
When using the default mode, `N` and `R` both have a TREESAME parent, so
those edges are walked and the others are ignored. The resulting history
@ -628,21 +628,21 @@ merge commits `O` and `P`. With parent rewriting, the resulting graph is:
@@ -628,21 +628,21 @@ merge commits `O` and `P`. With parent rewriting, the resulting graph is:
In this view, we see all of the important single-parent changes from
`A`, `B`, and `X`. We also see the carefully-resolved merge `M` and the
not-so-carefully-resolved merge `R`. This is usually enough information
to determine why the commits `A` and `B` "disappeared" from history in
the default view. However, there are a few issues with this approach.
+
The first issue is performance. Unlike any previous option, the
`--simplify-merges` option requires walking the entire commit history
before returning a single result. This can make the option difficult to
use for very large repositories.
+
The second issue is one of auditing. When many contributors are working
on the same repository, it is important which merge commits introduced
a change into an important branch. The problematic merge `R` above is
@ -671,10 +671,13 @@ important branch. Instead, the merge `N` was used to merge `R` and `X`
@@ -671,10 +671,13 @@ important branch. Instead, the merge `N` was used to merge `R` and `X`
into the important branch. This commit may have information about why
the change `X` came to override the changes from `A` and `B` in its
commit message.
--show-pulls::
In addition to the commits shown in the default history, show
each merge commit that is not TREESAME to its first parent but
is TREESAME to a later parent.
+
The `--show-pulls` option helps with both of these issues by adding more
merge commits to the history results. If a merge is not TREESAME to its
first parent but is TREESAME to a later parent, then that merge is
When a merge commit is included by `--show-pulls`, the merge is
treated as if it "pulled" the change from another branch. When using
`--show-pulls` on this example (and no other options) the resulting