bundle2: merge return values when bundle contains multiple changegroups

A bundle2 may contain multiple parts adding changegroups, in which case there
are multiple operation records for changegroups, each with its own return
value. Those multiple return values are aggregated in a single cgresult value
for the whole operation.

As can be seen in the associated test case, the situation with hooks is not
really the best, but without deeper thoughts and changes, we can't do much
better. Hopefully, things will be improved before bundle2 is enabled by default.
In the meanwhile, multiple changegroups is not expected to be in widespread
use, and even less expected to be used for pushes. Also, not many clients
cloning or pulling bundle2 with multiple changesets are not expected to have
changegroup hooks anyways.

tests/test-bundle2-multiple-changegroups.t

@@ -0,0 +1,261 b''
+Create an extension to test bundle2 with multiple changegroups
+
+  $ cat > bundle2.py <<EOF
+  > """
+  > """
+  > from mercurial import changegroup, exchange
+  > 
+  > def _getbundlechangegrouppart(bundler, repo, source, bundlecaps=None,
+  >                               b2caps=None, heads=None, common=None,
+  >                               **kwargs):
+  >     # Create two changegroups given the common changesets and heads for the
+  >     # changegroup part we are being requested. Use the parent of each head
+  >     # in 'heads' as intermediate heads for the first changegroup.
+  >     intermediates = [repo[r].p1().node() for r in heads]
+  >     cg = changegroup.getchangegroup(repo, source, heads=intermediates,
+  >                                      common=common, bundlecaps=bundlecaps)
+  >     bundler.newpart('b2x:output', data='changegroup1')
+  >     bundler.newpart('b2x:changegroup', data=cg.getchunks())
+  >     cg = changegroup.getchangegroup(repo, source, heads=heads,
+  >                                      common=common + intermediates,
+  >                                      bundlecaps=bundlecaps)
+  >     bundler.newpart('b2x:output', data='changegroup2')
+  >     bundler.newpart('b2x:changegroup', data=cg.getchunks())
+  > 
+  > def _pull(repo, *args, **kwargs):
+  >   pullop = _orig_pull(repo, *args, **kwargs)
+  >   repo.ui.write('pullop.cgresult is %d\n' % pullop.cgresult)
+  >   return pullop
+  > 
+  > _orig_pull = exchange.pull
+  > exchange.pull = _pull
+  > exchange.getbundle2partsmapping['changegroup'] = _getbundlechangegrouppart
+  > EOF
+
+  $ cat >> $HGRCPATH << EOF
+  > [experimental]
+  > bundle2-exp=True
+  > [ui]
+  > logtemplate={rev}:{node|short} {phase} {author} {bookmarks} {desc|firstline}
+  > EOF
+
+Start with a simple repository with a single commit
+
+  $ hg init repo
+  $ cd repo
+  $ cat > .hg/hgrc << EOF
+  > [extensions]
+  > bundle2=$TESTTMP/bundle2.py
+  > EOF
+
+  $ echo A > A
+  $ hg commit -A -m A -q
+  $ cd ..
+
+Clone
+
+  $ hg clone -q repo clone
+
+Add two linear commits
+
+  $ cd repo
+  $ echo B > B
+  $ hg commit -A -m B -q
+  $ echo C > C
+  $ hg commit -A -m C -q
+
+  $ cd ../clone
+  $ cat >> .hg/hgrc <<EOF
+  > [hooks]
+  > pretxnchangegroup = sh -c "python \"$TESTDIR/printenv.py\" pretxnchangegroup"
+  > changegroup = sh -c "python \"$TESTDIR/printenv.py\" changegroup"
+  > incoming = sh -c "python \"$TESTDIR/printenv.py\" incoming"
+  > EOF
+
+Pull the new commits in the clone
+
+  $ hg pull
+  pulling from $TESTTMP/repo (glob)
+  searching for changes
+  remote: changegroup1
+  adding changesets
+  adding manifests
+  adding file changes
+  added 1 changesets with 1 changes to 1 files
+  pretxnchangegroup hook: HG_NODE=27547f69f25460a52fff66ad004e58da7ad3fb56 HG_PENDING=$TESTTMP/clone HG_SOURCE=bundle2 HG_URL=bundle2
+  remote: changegroup2
+  adding changesets
+  adding manifests
+  adding file changes
+  added 1 changesets with 1 changes to 1 files
+  pretxnchangegroup hook: HG_NODE=f838bfaca5c7226600ebcfd84f3c3c13a28d3757 HG_PENDING=$TESTTMP/clone HG_PHASES_MOVED=1 HG_SOURCE=bundle2 HG_URL=bundle2
+  changegroup hook: HG_NODE=27547f69f25460a52fff66ad004e58da7ad3fb56 HG_SOURCE=bundle2 HG_URL=bundle2
+  incoming hook: HG_NODE=27547f69f25460a52fff66ad004e58da7ad3fb56 HG_SOURCE=bundle2 HG_URL=bundle2
+  changegroup hook: HG_NODE=f838bfaca5c7226600ebcfd84f3c3c13a28d3757 HG_PHASES_MOVED=1 HG_SOURCE=bundle2 HG_URL=bundle2
+  incoming hook: HG_NODE=f838bfaca5c7226600ebcfd84f3c3c13a28d3757 HG_SOURCE=bundle2 HG_URL=bundle2
+  pullop.cgresult is 1
+  (run 'hg update' to get a working copy)
+  $ hg update
+  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
+  $ hg log -G
+  @  2:f838bfaca5c7 public test  C
+  |
+  o  1:27547f69f254 public test  B
+  |
+  o  0:4a2df7238c3b public test  A
+  
+Add more changesets with multiple heads to the original repository
+
+  $ cd ../repo
+  $ echo D > D
+  $ hg commit -A -m D -q
+  $ hg up -r 1
+  0 files updated, 0 files merged, 2 files removed, 0 files unresolved
+  $ echo E > E
+  $ hg commit -A -m E -q
+  $ echo F > F
+  $ hg commit -A -m F -q
+  $ hg up -r 1
+  0 files updated, 0 files merged, 2 files removed, 0 files unresolved
+  $ echo G > G
+  $ hg commit -A -m G -q
+  $ hg up -r 3
+  2 files updated, 0 files merged, 1 files removed, 0 files unresolved
+  $ echo H > H
+  $ hg commit -A -m H -q
+  $ hg log -G
+  @  7:5cd59d311f65 draft test  H
+  |
+  | o  6:1d14c3ce6ac0 draft test  G
+  | |
+  | | o  5:7f219660301f draft test  F
+  | | |
+  | | o  4:8a5212ebc852 draft test  E
+  | |/
+  o |  3:b3325c91a4d9 draft test  D
+  | |
+  o |  2:f838bfaca5c7 draft test  C
+  |/
+  o  1:27547f69f254 draft test  B
+  |
+  o  0:4a2df7238c3b draft test  A
+  
+New heads are reported during transfer and properly accounted for in
+pullop.cgresult
+
+  $ cd ../clone
+  $ hg pull
+  pulling from $TESTTMP/repo (glob)
+  searching for changes
+  remote: changegroup1
+  adding changesets
+  adding manifests
+  adding file changes
+  added 2 changesets with 2 changes to 2 files (+1 heads)
+  pretxnchangegroup hook: HG_NODE=b3325c91a4d916bcc4cdc83ea3fe4ece46a42f6e HG_PENDING=$TESTTMP/clone HG_SOURCE=bundle2 HG_URL=bundle2
+  remote: changegroup2
+  adding changesets
+  adding manifests
+  adding file changes
+  added 3 changesets with 3 changes to 3 files (+1 heads)
+  pretxnchangegroup hook: HG_NODE=7f219660301fe4c8a116f714df5e769695cc2b46 HG_PENDING=$TESTTMP/clone HG_PHASES_MOVED=1 HG_SOURCE=bundle2 HG_URL=bundle2
+  changegroup hook: HG_NODE=b3325c91a4d916bcc4cdc83ea3fe4ece46a42f6e HG_SOURCE=bundle2 HG_URL=bundle2
+  incoming hook: HG_NODE=b3325c91a4d916bcc4cdc83ea3fe4ece46a42f6e HG_SOURCE=bundle2 HG_URL=bundle2
+  incoming hook: HG_NODE=8a5212ebc8527f9fb821601504794e3eb11a1ed3 HG_SOURCE=bundle2 HG_URL=bundle2
+  changegroup hook: HG_NODE=7f219660301fe4c8a116f714df5e769695cc2b46 HG_PHASES_MOVED=1 HG_SOURCE=bundle2 HG_URL=bundle2
+  incoming hook: HG_NODE=7f219660301fe4c8a116f714df5e769695cc2b46 HG_SOURCE=bundle2 HG_URL=bundle2
+  incoming hook: HG_NODE=1d14c3ce6ac0582d2809220d33e8cd7a696e0156 HG_SOURCE=bundle2 HG_URL=bundle2
+  incoming hook: HG_NODE=5cd59d311f6508b8e0ed28a266756c859419c9f1 HG_SOURCE=bundle2 HG_URL=bundle2
+  pullop.cgresult is 3
+  (run 'hg heads' to see heads, 'hg merge' to merge)
+  $ hg log -G
+  o  7:5cd59d311f65 public test  H
+  |
+  | o  6:1d14c3ce6ac0 public test  G
+  | |
+  | | o  5:7f219660301f public test  F
+  | | |
+  | | o  4:8a5212ebc852 public test  E
+  | |/
+  o |  3:b3325c91a4d9 public test  D
+  | |
+  @ |  2:f838bfaca5c7 public test  C
+  |/
+  o  1:27547f69f254 public test  B
+  |
+  o  0:4a2df7238c3b public test  A
+  
+Removing a head from the original repository by merging it
+
+  $ cd ../repo
+  $ hg merge -r 6 -q
+  $ hg commit -m Merge
+  $ echo I > I
+  $ hg commit -A -m H -q
+  $ hg log -G
+  @  9:9d18e5bd9ab0 draft test  H
+  |
+  o    8:71bd7b46de72 draft test  Merge
+  |\
+  | o  7:5cd59d311f65 draft test  H
+  | |
+  o |  6:1d14c3ce6ac0 draft test  G
+  | |
+  | | o  5:7f219660301f draft test  F
+  | | |
+  +---o  4:8a5212ebc852 draft test  E
+  | |
+  | o  3:b3325c91a4d9 draft test  D
+  | |
+  | o  2:f838bfaca5c7 draft test  C
+  |/
+  o  1:27547f69f254 draft test  B
+  |
+  o  0:4a2df7238c3b draft test  A
+  
+Removed heads are reported during transfer and properly accounted for in
+pullop.cgresult
+
+  $ cd ../clone
+  $ hg pull
+  pulling from $TESTTMP/repo (glob)
+  searching for changes
+  remote: changegroup1
+  adding changesets
+  adding manifests
+  adding file changes
+  added 1 changesets with 0 changes to 0 files (-1 heads)
+  pretxnchangegroup hook: HG_NODE=71bd7b46de72e69a32455bf88d04757d542e6cf4 HG_PENDING=$TESTTMP/clone HG_SOURCE=bundle2 HG_URL=bundle2
+  remote: changegroup2
+  adding changesets
+  adding manifests
+  adding file changes
+  added 1 changesets with 1 changes to 1 files
+  pretxnchangegroup hook: HG_NODE=9d18e5bd9ab09337802595d49f1dad0c98df4d84 HG_PENDING=$TESTTMP/clone HG_PHASES_MOVED=1 HG_SOURCE=bundle2 HG_URL=bundle2
+  changegroup hook: HG_NODE=71bd7b46de72e69a32455bf88d04757d542e6cf4 HG_SOURCE=bundle2 HG_URL=bundle2
+  incoming hook: HG_NODE=71bd7b46de72e69a32455bf88d04757d542e6cf4 HG_SOURCE=bundle2 HG_URL=bundle2
+  changegroup hook: HG_NODE=9d18e5bd9ab09337802595d49f1dad0c98df4d84 HG_PHASES_MOVED=1 HG_SOURCE=bundle2 HG_URL=bundle2
+  incoming hook: HG_NODE=9d18e5bd9ab09337802595d49f1dad0c98df4d84 HG_SOURCE=bundle2 HG_URL=bundle2
+  pullop.cgresult is -2
+  (run 'hg update' to get a working copy)
+  $ hg log -G
+  o  9:9d18e5bd9ab0 public test  H
+  |
+  o    8:71bd7b46de72 public test  Merge
+  |\
+  | o  7:5cd59d311f65 public test  H
+  | |
+  o |  6:1d14c3ce6ac0 public test  G
+  | |
+  | | o  5:7f219660301f public test  F
+  | | |
+  +---o  4:8a5212ebc852 public test  E
+  | |
+  | o  3:b3325c91a4d9 public test  D
+  | |
+  | @  2:f838bfaca5c7 public test  C
+  |/
+  o  1:27547f69f254 public test  B
+  |
+  o  0:4a2df7238c3b public test  A
+  

mercurial/exchange.py

@@ -944,8 +944,22 b' def _pullbundle2(pullop):'
         raise util.Abort('missing support for %s' % exc)
 
     if pullop.fetch:
-        assert len(op.records['changegroup']) == 1
-        pullop.cgresult = op.records['changegroup'][0]['return']
+        changedheads = 0
+        pullop.cgresult = 1
+        for cg in op.records['changegroup']:
+            ret = cg['return']
+            # If any changegroup result is 0, return 0
+            if ret == 0:
+                pullop.cgresult = 0
+                break
+            if ret < -1:
+                changedheads += ret + 1
+            elif ret > 1:
+                changedheads += ret - 1
+        if changedheads > 0:
+            pullop.cgresult = 1 + changedheads
+        elif changedheads < 0:
+            pullop.cgresult = -1 + changedheads
 
     # processing phases change
     for namespace, value in op.records['listkeys']: