Merge branch 'jk/log-fp-implies-m'

"git log --first-parent -p" showed patches only for single-parent
commits on the first-parent chain; the "--first-parent" option has
been made to imply "-m".  Use "--no-diff-merges" to restore the
previous behaviour to omit patches for merge commits.

* jk/log-fp-implies-m:
  doc/git-log: clarify handling of merge commit diffs
  doc/git-log: move "-t" into diff-options list
  doc/git-log: drop "-r" diff option
  doc/git-log: move "Diff Formatting" from rev-list-options
  log: enable "-m" automatically with "--first-parent"
  revision: add "--no-diff-merges" option to counteract "-m"
  log: drop "--cc implies -m" logic

Documentation/diff-options.txt

@@ -73,6 +73,11 @@ ifndef::git-format-patch[]
 	Synonym for `-p --raw`.
 endif::git-format-patch[]
 
+ifdef::git-log[]
+-t::
+	Show the tree objects in the diff output.
+endif::git-log[]
+
 --indent-heuristic::
 	Enable the heuristic that shifts diff hunk boundaries to make patches
 	easier to read. This is the default.

Documentation/git-log.txt

@@ -114,8 +114,47 @@ include::rev-list-options.txt[]
 
 include::pretty-formats.txt[]
 
-COMMON DIFF OPTIONS
--------------------
+DIFF FORMATTING
+---------------
+
+By default, `git log` does not generate any diff output. The options
+below can be used to show the changes made by each commit.
+
+Note that unless one of `-c`, `--cc`, or `-m` is given, merge commits
+will never show a diff, even if a diff format like `--patch` is
+selected, nor will they match search options like `-S`. The exception is
+when `--first-parent` is in use, in which merges are treated like normal
+single-parent commits (this can be overridden by providing a
+combined-diff option or with `--no-diff-merges`).
+
+-c::
+	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.
+
+--cc::
+	This flag implies the `-c` option and further compresses the
+	patch output by omitting uninteresting hunks whose contents in
+	the parents have only two variants and the merge result picks
+	one of them without modification.
+
+--combined-all-paths::
+	This flag causes combined diffs (used for merge commits) to
+	list the name of the file from all parents.  It thus only has
+	effect when -c or --cc are specified, and is likely only
+	useful if filename changes are detected (i.e. when either
+	rename or copy detection have been requested).
+
+-m::
+--diff-merges::
+	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.
 
 :git-log: 1
 include::diff-options.txt[]

Documentation/rev-list-options.txt

@@ -1116,48 +1116,3 @@ ifdef::git-rev-list[]
 	by a tab.
 endif::git-rev-list[]
 endif::git-shortlog[]
-
-ifndef::git-shortlog[]
-ifndef::git-rev-list[]
-Diff Formatting
-~~~~~~~~~~~~~~~
-
-Listed below are options that control the formatting of diff output.
-Some of them are specific to linkgit:git-rev-list[1], however other diff
-options may be given. See linkgit:git-diff-files[1] for more options.
-
--c::
-	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.
-
---cc::
-	This flag implies the `-c` option and further compresses the
-	patch output by omitting uninteresting hunks whose contents in
-	the parents have only two variants and the merge result picks
-	one of them without modification.
-
---combined-all-paths::
-	This flag causes combined diffs (used for merge commits) to
-	list the name of the file from all parents.  It thus only has
-	effect when -c or --cc are specified, and is likely only
-	useful if filename changes are detected (i.e. when either
-	rename or copy detection have been requested).
-
--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.
-
--t::
-	Show the tree objects in the diff output. This implies `-r`.
-endif::git-rev-list[]
-endif::git-shortlog[]