hooks: add HG_NODE_LAST to txnclose and changegroup hook environments
Sometimes a txnclose or changegroup hook wants to iterate through all
the changesets in transaction: in that situation usually the revset
`$HG_NODE:` is used to select the revisions. Unfortunately this revset
sometimes may contain too many changesets because we don't have the
write lock while the hook runs newer changes may be added to
repository in the meantime.
That's why there is a need for extra variable carrying the information about
the last change in the transaction.
'a' in d: True
d['a']: va
'b' in d: True
d['b']: vb
'c' in d: True
d['c']: vc
'd' in d: True
d['d']: vd
'a' in d: False
'b' in d: True
d['b']: vb
'c' in d: True
d['c']: vc
'd' in d: True
d['d']: vd
'e' in d: True
d['e']: ve
'b' in d: True
d['b']: vb2
'c' in d: True
d['c']: vc2
'd' in d: True
d['d']: vd
'e' in d: False
'f' in d: True
d['f']: vf
'b' in d: False
'c' in d: False
'd' in d: False
'e' in d: False
'f' in d: False
'a' in d: True
d['a']: 1
'b' in d: True
d['b']: 2
All of these should be present:
'a' in dc: True
dc['a']: va3
'b' in dc: True
dc['b']: vb3
'c' in dc: True
dc['c']: vc3
'd' in dc: True
dc['d']: vd3
All of these except 'a' should be present:
'a' in dc: False
'b' in dc: True
dc['b']: vb3
'c' in dc: True
dc['c']: vc3
'd' in dc: True
dc['d']: vd3
'e' in dc: True
dc['e']: ve3
These should be in reverse alphabetical order and read 'v?3':
d['d']: vd3
d['c']: vc3
d['b']: vb3
d['a']: va3