diff tests/test-bookmarks.t @ 28029:72072cfc7e91

update: warn about other topological heads on bare update

A concern around the user experience of Mercurial is user getting stuck on there
own topological branch forever. For example, someone pulling another topological
branch, missing that message in pull asking them to merge and getting stuck on
there own local branch.

The current way to "address" this concern was for bare 'hg update' to target the
tipmost (also latest pulled) changesets and complain when the update was not
linear. That way, failure to merge newly pulled changesets would result in some
kind of failure.

Yet the failure was quite obscure, not working in all cases (eg: commit right
after pull) and the behavior was very impractical in the common case
(eg: issue4673).

To be able to change that behavior, we need to provide other ways to alert a
user stucks on one of many topological head. We do so with an extra message after
bare update:

  1 other heads for branch "default"

Bookmark get its own special version:

  1 other divergent bookmarks for "foobar"

There is significant room to improve the message itself, and we should augment
it with hint about how to see theses other heads or handle the situation (see
in-line comment). But having "a" message is already a significant improvement
compared to the existing situation. Once we have it we can iterate on a better
version of it. As having such message is an important step toward changing the
default destination for update and other nicety, I would like to move forward
quickly on getting such message.

This was discussed during London - October 2015 Sprint.

--- a/tests/test-bookmarks.t	Wed Feb 03 04:37:04 2016 +0000
+++ b/tests/test-bookmarks.t	Tue Feb 02 14:49:02 2016 +0000
@@ -573,6 +573,7 @@
   $ hg bookmark -r3 Y
   moving bookmark 'Y' forward from db815d6d32e6
   $ cp -r  ../cloned-bookmarks-update ../cloned-bookmarks-manual-update
+  $ cp -r  ../cloned-bookmarks-update ../cloned-bookmarks-manual-update-with-divergence
 
 (manual version)
 
@@ -617,6 +618,34 @@
   updating to active bookmark Y
   1 files updated, 0 files merged, 0 files removed, 0 files unresolved
 
+We warn about divergent during bare update to the active bookmark
+
+  $ hg -R ../cloned-bookmarks-manual-update-with-divergence update Y
+  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
+  (activating bookmark Y)
+  $ hg -R ../cloned-bookmarks-manual-update-with-divergence bookmarks -r X2 Y@1
+  $ hg -R ../cloned-bookmarks-manual-update-with-divergence bookmarks
+     X2                        1:925d80f479bb
+   * Y                         2:db815d6d32e6
+     Y@1                       1:925d80f479bb
+     Z                         2:db815d6d32e6
+     x  y                      2:db815d6d32e6
+  $ hg -R ../cloned-bookmarks-manual-update-with-divergence pull
+  pulling from $TESTTMP
+  searching for changes
+  adding changesets
+  adding manifests
+  adding file changes
+  added 2 changesets with 2 changes to 2 files (+1 heads)
+  updating bookmark Y
+  updating bookmark Z
+  (run 'hg heads' to see heads, 'hg merge' to merge)
+  $ hg -R ../cloned-bookmarks-manual-update-with-divergence update
+  updating to active bookmark Y
+  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
+  (activating bookmark Y)
+  1 other divergent bookmarks for "Y"
+
 test wrongly formated bookmark
 
   $ echo '' >> .hg/bookmarks
@@ -715,6 +744,7 @@
   $ hg up -C
   1 files updated, 0 files merged, 1 files removed, 0 files unresolved
   (leaving bookmark drop)
+  1 other heads for branch "default"
   $ hg sum
   parent: 2:db815d6d32e6 
    2