Merge branch 'sk/force-if-includes'

"git push --force-with-lease[=<ref>]" can easily be misused to lose
commits unless the user takes good care of their own "git fetch".
A new option "--force-if-includes" attempts to ensure that what is
being force-pushed was created after examining the commit at the
tip of the remote ref that is about to be force-replaced.

* sk/force-if-includes:
  t, doc: update tests, reference for "--force-if-includes"
  push: parse and set flag for "--force-if-includes"
  push: add reflog check for "--force-if-includes"

3 files changed, 37 insertions, 4 deletions

diff --git a/Documentation/config/advice.txt b/Documentation/config/advice.txt
index bdd37c3eaa..acbd0c09aa 100644
--- a/Documentation/config/advice.txt
+++ b/Documentation/config/advice.txt
@@ -10,9 +10,8 @@ advice.*::
 		that the check is disabled.
 	pushUpdateRejected::
 		Set this variable to 'false' if you want to disable
-		'pushNonFFCurrent',
-		'pushNonFFMatching', 'pushAlreadyExists',
-		'pushFetchFirst', and 'pushNeedsForce'
+		'pushNonFFCurrent', 'pushNonFFMatching', 'pushAlreadyExists',
+		'pushFetchFirst', 'pushNeedsForce', and 'pushRefNeedsUpdate'
 		simultaneously.
 	pushNonFFCurrent::
 		Advice shown when linkgit:git-push[1] fails due to a
@@ -41,6 +40,10 @@ advice.*::
 		we can still suggest that the user push to either
 		refs/heads/* or refs/tags/* based on the type of the
 		source object.
+	pushRefNeedsUpdate::
+		Shown when linkgit:git-push[1] rejects a forced update of
+		a branch when its remote-tracking ref has updates that we
+		do not have locally.
 	statusAheadBehind::
 		Shown when linkgit:git-status[1] computes the ahead/behind
 		counts for a local ref compared to its remote tracking ref,
diff --git a/Documentation/config/push.txt b/Documentation/config/push.txt
index f5e5b38c68..21b256e0a4 100644
--- a/Documentation/config/push.txt
+++ b/Documentation/config/push.txt
@@ -114,3 +114,9 @@ push.recurseSubmodules::
 	specifying '--recurse-submodules=check|on-demand|no'.
 	If not set, 'no' is used by default, unless 'submodule.recurse' is
 	set (in which case a 'true' value means 'on-demand').
+
+push.useForceIfIncludes::
+	If set to "true", it is equivalent to specifying
+	`--force-if-includes` as an option to linkgit:git-push[1]
+	in the command line. Adding `--no-force-if-includes` at the
+	time of push overrides this configuration setting.
diff --git a/Documentation/git-push.txt b/Documentation/git-push.txt
index 3b8053447e..ab103c82cf 100644
--- a/Documentation/git-push.txt
+++ b/Documentation/git-push.txt
@@ -13,7 +13,7 @@ SYNOPSIS
 	   [--repo=<repository>] [-f | --force] [-d | --delete] [--prune] [-v | --verbose]
 	   [-u | --set-upstream] [-o <string> | --push-option=<string>]
 	   [--[no-]signed|--signed=(true|false|if-asked)]
-	   [--force-with-lease[=<refname>[:<expect>]]]
+	   [--force-with-lease[=<refname>[:<expect>]] [--force-if-includes]]
 	   [--no-verify] [<repository> [<refspec>...]]
 
 DESCRIPTION
@@ -320,6 +320,14 @@ seen and are willing to overwrite, then rewrite history, and finally
 force push changes to `master` if the remote version is still at
 `base`, regardless of what your local `remotes/origin/master` has been
 updated to in the background.
++
+Alternatively, specifying `--force-if-includes` as an ancillary option
+along with `--force-with-lease[=<refname>]` (i.e., without saying what
+exact commit the ref on the remote side must be pointing at, or which
+refs on the remote side are being protected) at the time of "push" will
+verify if updates from the remote-tracking refs that may have been
+implicitly updated in the background are integrated locally before
+allowing a forced update.
 
 -f::
 --force::
@@ -341,6 +349,22 @@ one branch, use a `+` in front of the refspec to push (e.g `git push
 origin +master` to force a push to the `master` branch). See the
 `<refspec>...` section above for details.
 
+--[no-]force-if-includes::
+	Force an update only if the tip of the remote-tracking ref
+	has been integrated locally.
++
+This option enables a check that verifies if the tip of the
+remote-tracking ref is reachable from one of the "reflog" entries of
+the local branch based in it for a rewrite. The check ensures that any
+updates from the remote have been incorporated locally by rejecting the
+forced update if that is not the case.
++
+If the option is passed without specifying `--force-with-lease`, or
+specified along with `--force-with-lease=<refname>:<expect>`, it is
+a "no-op".
++
+Specifying `--no-force-if-includes` disables this behavior.
+
 --repo=<repository>::
 	This option is equivalent to the <repository> argument. If both
 	are specified, the command-line argument takes precedence.