Merge branch 'pb/log-first-parent-p-m'

* pb/log-first-parent-p-m:
  show --first-parent/-m: do not default to --cc
  show -c: show patch text
  revision: introduce setup_revision_opt
  t4013: add tests for log -p -m --first-parent
  git log -p -m: document -m and honor --first-parent

3 files changed, 22 insertions, 3 deletions

diff --git a/Documentation/diff-generate-patch.txt b/Documentation/diff-generate-patch.txt
index 0f25ba7e38..8f9a2412fd 100644
--- a/Documentation/diff-generate-patch.txt
+++ b/Documentation/diff-generate-patch.txt
@@ -56,7 +56,8 @@ combined diff format
 
 "git-diff-tree", "git-diff-files" and "git-diff" can take '-c' or
 '--cc' option to produce 'combined diff'.  For showing a merge commit
-with "git log -p", this is the default format.
+with "git log -p", this is the default format; you can force showing
+full diff with the '-m' option.
 A 'combined diff' format looks like this:
 
 ------------
diff --git a/Documentation/git-log.txt b/Documentation/git-log.txt
index 0e39bb61ee..fb184ba186 100644
--- a/Documentation/git-log.txt
+++ b/Documentation/git-log.txt
@@ -118,6 +118,15 @@ git log master --not --remotes=*/master::
 	Shows all commits that are in local master but not in any remote
 	repository master branches.
 
+git log -p -m --first-parent::
+
+	Shows the history including change diffs, but only from the
+	"main branch" perspective, skipping commits that come from merged
+	branches, and showing full diffs of changes introduced by the merges.
+	This makes sense only when following a strict policy of merging all
+	topic branches when staying on a single integration branch.
+
+
 Discussion
 ----------
 
diff --git a/Documentation/rev-list-options.txt b/Documentation/rev-list-options.txt
index 81c0e6f184..b9fb7a86bd 100644
--- a/Documentation/rev-list-options.txt
+++ b/Documentation/rev-list-options.txt
@@ -108,8 +108,8 @@ options may be given. See linkgit:git-diff-files[1] for more options.
 
 -c::
 
-	This flag changes the way a merge commit is displayed.  It shows
-	the differences from each of the parents to the merge result
+	With this option, diff output for a merge commit
+	shows the differences from each of the parents to the merge result
 	simultaneously instead of showing pairwise diff between a parent
 	and the result one at a time. Furthermore, it lists only files
 	which were modified from all parents.
@@ -121,6 +121,15 @@ options may be given. See linkgit:git-diff-files[1] for more options.
 	the parents have only two variants and the merge result picks
 	one of them without modification.
 
+-m::
+
+	This flag makes the merge commits show the full diff like
+	regular commits; for each merge parent, a separate log entry
+	and diff is generated. An exception is that only diff against
+	the first parent is shown when '--first-parent' option is given;
+	in that case, the output represents the changes the merge
+	brought _into_ the then-current branch.
+
 -r::
 
 	Show recursive diffs.