[PATCH 3 of 4 V4] update: allow setting default update check to "noconflict"

[Martin von Zweigbergk]

# HG changeset patch
# User Martin von Zweigbergk <martinvonz at google.com>
# Date 1486973155 28800
#      Mon Feb 13 00:05:55 2017 -0800
# Node ID 572ffc6ab9724bb7b1d4d3315fd8deaf9d52461a
# Parent  ce8d9fd4b41df0744a456de37ad5e93c8ca1d1db
update: allow setting default update check to "noconflict"

The new value allows update (linear or not) as long as they don't
result in file merges.

I'm hoping that this value can some day become the default.

diff -r ce8d9fd4b41d -r 572ffc6ab972 mercurial/hg.py
--- a/mercurial/hg.py	Mon Feb 13 16:03:05 2017 -0800
+++ b/mercurial/hg.py	Mon Feb 13 00:05:55 2017 -0800
@@ -733,12 +733,13 @@
      * none: don't check (merge working directory changes into destination)
      * linear: check that update is linear before merging working directory
                changes into destination
+     * noconflict: check that the update does not result in file merges
 
     This returns whether conflict is detected at updating or not.
     """
     if updatecheck is None:
         updatecheck = ui.config('experimental', 'updatecheck')
-        if updatecheck not in ('abort', 'none', 'linear'):
+        if updatecheck not in ('abort', 'none', 'linear', 'noconflict'):
             # If not configured, or invalid value configured
             updatecheck = 'linear'
     with repo.wlock():
diff -r ce8d9fd4b41d -r 572ffc6ab972 mercurial/merge.py
--- a/mercurial/merge.py	Mon Feb 13 16:03:05 2017 -0800
+++ b/mercurial/merge.py	Mon Feb 13 00:05:55 2017 -0800
@@ -1501,7 +1501,7 @@
         # updatecheck='abort' to better suppport some of these callers.
         if updatecheck is None:
             updatecheck = 'linear'
-        assert updatecheck in ('none', 'linear')
+        assert updatecheck in ('none', 'linear', 'noconflict')
     # If we're doing a partial update, we need to skip updating
     # the dirstate, so make a note of any partial-ness to the
     # update here.
@@ -1595,6 +1595,13 @@
             repo, wc, p2, pas, branchmerge, force, mergeancestor,
             followcopies, matcher=matcher, mergeforce=mergeforce)
 
+        if updatecheck == 'noconflict':
+            for f, (m, args, msg) in actionbyfile.iteritems():
+                if m not in ('g', 'k', 'r'):
+                    msg = _("uncommitted changes")
+                    hint = _("commit or update --merge to allow merge")
+                    raise error.Abort(msg, hint=hint)
+
         # Prompt and create actions. Most of this is in the resolve phase
         # already, but we can't handle .hgsubstate in filemerge or
         # subrepo.submerge yet so we have to keep prompting for it.
diff -r ce8d9fd4b41d -r 572ffc6ab972 tests/test-update-branches.t
--- a/tests/test-update-branches.t	Mon Feb 13 16:03:05 2017 -0800
+++ b/tests/test-update-branches.t	Mon Feb 13 00:05:55 2017 -0800
@@ -255,6 +255,65 @@
   >>>>>>> destination:  d047485b3896 b1 - test: 4
   $ rm a.orig
 
+  $ echo 'updatecheck = noconflict' >> .hg/hgrc
+
+  $ revtest 'none dirty cross'  dirty 3 4
+  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
+  parent=4
+  M foo
+
+  $ revtest 'none dirty linear' dirty 1 2
+  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
+  parent=2
+  M foo
+
+  $ revtest 'none dirty linear' dirty 1 2 -c
+  abort: uncommitted changes
+  parent=1
+  M foo
+
+  $ revtest 'none dirty linear' dirty 1 2 -C
+  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
+  parent=2
+
+Locally added file is allowed
+  $ hg up -qC 3
+  $ echo a > bar
+  $ hg add bar
+  $ hg up -q 4
+  $ hg st
+  A bar
+  $ hg forget bar
+  $ rm bar
+
+Locally removed file is allowed
+  $ hg up -qC 3
+  $ hg rm a
+  $ hg up -q 4
+  abort: uncommitted changes
+  (commit or update --merge to allow merge)
+  [255]
+
+File conflict is not allowed
+  $ hg up -qC 3
+  $ echo dirty >> a
+  $ hg up -q 4
+  abort: uncommitted changes
+  (commit or update --merge to allow merge)
+  [255]
+  $ hg up -m 4
+  merging a
+  warning: conflicts while merging a! (edit, then use 'hg resolve --mark')
+  0 files updated, 0 files merged, 0 files removed, 1 files unresolved
+  use 'hg resolve' to retry unresolved file merges
+  [1]
+  $ rm a.orig
+
+Change/delete conflict is not allowed
+  $ hg up -qC 3
+  $ hg rm foo
+  $ hg up -q 4
+
 Uses default value of "linear" when value is misspelled
   $ echo 'updatecheck = linyar' >> .hg/hgrc