Merge branch 'mm/maint-hint-failed-merge'

* mm/maint-hint-failed-merge:
user-manual: Document that "git merge" doesn't like uncommited changes.
merge-recursive: point the user to commit when file would be overwritten.

diff --git a/Documentation/config.txt b/Documentation/config.txt
index 657f0016d39863770bd41f0eed5f746b6915516b..a8e0876a2add7bb53d3194b1f5e0a2031dd19a42 100644 (file)
--- a/Documentation/config.txt
+++ b/Documentation/config.txt
@@ -126,6 +126,10 @@ advice.*::
                Directions on how to stage/unstage/add shown in the
                output of linkgit:git-status[1] and the template shown
                when writing commit messages. Default: true.
+       commitBeforeMerge::
+               Advice shown when linkgit:git-merge[1] refuses to
+               merge to avoid overwritting local changes.
+               Default: true.
 --
 
 core.fileMode::

diff --git a/Documentation/user-manual.txt b/Documentation/user-manual.txt
index 27d97b6d1e7705dd4025a33b5b9ab668cfaa15e1..b169836684a56aae176875effa5cc4e6a619de80 100644 (file)
--- a/Documentation/user-manual.txt
+++ b/Documentation/user-manual.txt
@@ -1183,7 +1183,23 @@ $ git merge branchname
 -------------------------------------------------
 
 merges the development in the branch "branchname" into the current
-branch.  If there are conflicts--for example, if the same file is
+branch.
+
+A merge is made by combining the changes made in "branchname" and the
+changes made up to the latest commit in your current branch since
+their histories forked. The work tree is overwritten by the result of
+the merge when this combining is done cleanly, or overwritten by a
+half-merged results when this combining results in conflicts.
+Therefore, if you have uncommitted changes touching the same files as
+the ones impacted by the merge, Git will refuse to proceed. Most of
+the time, you will want to commit your changes before you can merge,
+and if you don't, then linkgit:git-stash[1] can take these changes
+away while you're doing the merge, and reapply them afterwards.
+
+If the changes are independant enough, Git will automatically complete
+the merge and commit the result (or reuse an existing commit in case
+of <<fast-forwards,fast-forward>>, see below). On the other hand,
+if there are conflicts--for example, if the same file is
 modified in two different ways in the remote branch and the local
 branch--then you are warned; the output may look something like this:
 
@@ -1679,7 +1695,7 @@ Sharing development with others
 Getting updates with git pull
 -----------------------------
 
-After you clone a repository and make a few changes of your own, you
+After you clone a repository and commit a few changes of your own, you
 may wish to check the original repository for updates and merge them
 into your own work.
 

diff --git a/advice.c b/advice.c
index ae4b1e81dfea0f63db10691ba0005c8888fd6dc7..cb666acc3cf8fdda777febbefac455f3667759f1 100644 (file)
--- a/advice.c
+++ b/advice.c
@@ -2,6 +2,7 @@
 
 int advice_push_nonfastforward = 1;
 int advice_status_hints = 1;
+int advice_commit_before_merge = 1;
 
 static struct {
        const char *name;
@@ -9,6 +10,7 @@ static struct {
 } advice_config[] = {
        { "pushnonfastforward", &advice_push_nonfastforward },
        { "statushints", &advice_status_hints },
+       { "commitbeforemerge", &advice_commit_before_merge },
 };
 
 int git_default_advice_config(const char *var, const char *value)

diff --git a/advice.h b/advice.h
index e9df8e026c301767b12217ba0374860a15742f2e..3de5000d8cb35c1d2c31867b942a54b487bed836 100644 (file)
--- a/advice.h
+++ b/advice.h
@@ -3,6 +3,7 @@
 
 extern int advice_push_nonfastforward;
 extern int advice_status_hints;
+extern int advice_commit_before_merge;
 
 int git_default_advice_config(const char *var, const char *value);
 

diff --git a/merge-recursive.c b/merge-recursive.c
index baabe2c35647d65716d1b82473846e80cc02957b..a91208f295d00d73b8fc0f5cd6a92ac422d9eeb4 100644 (file)
--- a/merge-recursive.c
+++ b/merge-recursive.c
@@ -3,6 +3,7 @@
  * Fredrik Kuivinen.
  * The thieves were Alex Riesen and Johannes Schindelin, in June/July 2006
  */
+#include "advice.h"
 #include "cache.h"
 #include "cache-tree.h"
 #include "commit.h"
@@ -171,7 +172,7 @@ static int git_merge_trees(int index_only,
        int rc;
        struct tree_desc t[3];
        struct unpack_trees_options opts;
-       static const struct unpack_trees_error_msgs msgs = {
+       struct unpack_trees_error_msgs msgs = {
                /* would_overwrite */
                "Your local changes to '%s' would be overwritten by merge.  Aborting.",
                /* not_uptodate_file */
@@ -183,6 +184,11 @@ static int git_merge_trees(int index_only,
                /* bind_overlap -- will not happen here */
                NULL,
        };
+       if (advice_commit_before_merge) {
+               msgs.would_overwrite = msgs.not_uptodate_file =
+                       "Your local changes to '%s' would be overwritten by merge.  Aborting.\n"
+                       "Please, commit your changes or stash them before you can merge.";
+       }
 
        memset(&opts, 0, sizeof(opts));
        if (index_only)