# HG changeset patch
# User mpm@selenic.com
# Date 1120357515 28800
# Node ID ffeb2c3a19669102df8110b513fa163d0da36e7f
# Parent  e33c85d2812a5f6cfdff9caed9ef6c7c72b88499
Actually warn on pulling from an unrelated repository

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Hash: SHA1

Actually warn on pulling from an unrelated repository

add some comments to findincoming
track the base nodes of the fetch set
report if the base set only contains nullid
add a test case

manifest hash: 3fc038a6041b0967a20503f5ec8876efc038841a
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diff --git a/mercurial/hg.py b/mercurial/hg.py
--- a/mercurial/hg.py
+++ b/mercurial/hg.py
@@ -852,6 +852,7 @@ class localrepository:
         m = self.changelog.nodemap
         search = []
         fetch = []
+        base = {}
         seen = {}
         seenbranch = {}
 
@@ -861,6 +862,7 @@ class localrepository:
             return [nullid]
 
         # otherwise, assume we're closer to the tip than the root
+        # and start by examining the heads
         self.ui.status("searching for changes\n")
         heads = remote.heads()
         unknown = []
@@ -874,6 +876,10 @@ class localrepository:
         rep = {}
         reqcnt = 0
 
+        # search through remote branches
+        # a 'branch' here is a linear segment of history, with four parts:
+        # head, root, first parent, second parent
+        # (a branch always has two parents (or none) by definition)
         unknown = remote.branches(unknown)
         while unknown:
             r = []
@@ -899,6 +905,7 @@ class localrepository:
                             self.ui.debug("found new changeset %s\n" %
                                           short(n[1]))
                             fetch.append(n[1]) # earliest unknown
+                            base[n[2]] = 1 # latest known
                             continue
 
                     for a in n[2:4]:
@@ -919,6 +926,7 @@ class localrepository:
                         if b[0] not in m and b[0] not in seen:
                             unknown.append(b)
 
+        # do binary search on the branches we found
         while search:
             n = search.pop(0)
             reqcnt += 1
@@ -933,6 +941,7 @@ class localrepository:
                         self.ui.debug("found new branch changeset %s\n" %
                                           short(p))
                         fetch.append(p)
+                        base[i] = 1
                     else:
                         self.ui.debug("narrowed branch search to %s:%s\n"
                                       % (short(p), short(i)))
@@ -940,11 +949,12 @@ class localrepository:
                     break
                 p, f = i, f * 2
 
+        # sanity check our fetch list
         for f in fetch:
             if f in m:
                 raise RepoError("already have changeset " + short(f[:4]))
 
-        if fetch == [nullid]:
+        if base.keys() == [nullid]:
             self.ui.warn("warning: pulling from an unrelated repository!\n")
 
         self.ui.note("adding new changesets starting at " +
diff --git a/tests/test-unrelated-pull b/tests/test-unrelated-pull
new file mode 100755
--- /dev/null
+++ b/tests/test-unrelated-pull
@@ -0,0 +1,17 @@
+mkdir a
+cd a
+hg init
+echo 123 > a
+hg add a
+hg commit -t "a" -u a -d "0 0"
+
+cd ..
+mkdir b
+cd b
+hg init 
+echo 321 > b
+hg add b
+hg commit -t "b" -u b -d "0 0"
+
+hg pull ../a
+hg heads
diff --git a/tests/test-unrelated-pull.out b/tests/test-unrelated-pull.out
new file mode 100644
--- /dev/null
+++ b/tests/test-unrelated-pull.out
@@ -0,0 +1,19 @@
+pulling from ../a
+searching for changes
+warning: pulling from an unrelated repository!
+adding changesets
+adding manifests
+adding file revisions
+modified 1 files, added 1 changesets and 1 new revisions
+(run 'hg update' to get a working copy)
+changeset:   1:9a79c33a9db37480e40fbd2a65d62ebd2a3c441c
+tag:         tip
+user:        a
+date:        Thu Jan  1 00:00:00 1970
+summary:     a
+
+changeset:   0:01f8062b2de51c0fa6428c5db1d1b3ea780189df
+user:        b
+date:        Thu Jan  1 00:00:00 1970
+summary:     b
+