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Author	SHA1	Message	Date
Junio C Hamano	1ee26571e9	traverse_trees(): handle D/F conflict case sanely traverse_trees() is supposed to call its callback with all the matching entries from the given trees. The current algorithm keeps a pointer to each of the tree being traversed, and feeds the entry with the earliest name to the callback. This breaks down if the trees being traversed looks like this: A B t-1 t t-2 u t/a v When we are currently looking at an entry "t-1" in tree A, and tree B has returned "t", feeding "t" from the B and not feeding anything from A, only because "t-1" sorts later than "t", will miss an entry for a subtree "t" behind the current entry in tree A. This introduces extended_entry_extract() helper function that gives what name is expected from the tree, and implements a mechanism to look-ahead in the tree object using it, to make sure such a case is handled sanely. Traversal in tree A in the above example will first return "t" to match that of B, and then the next request for an entry to A then returns "t-1". This roughly corresponds to what Linus's "prepare for one-entry lookahead" wanted to do, but because this does implement look ahead, t6035 and one more test in t1012 reveal that the approach would not work without adjusting the side that walks the index in unpack_trees() as well. Signed-off-by: Junio C Hamano <gitster@pobox.com>	15 years ago
Junio C Hamano	934f930b31	more D/F conflict tests Before starting to muck with this code, let's expose the current breakages that we intend to fix. Signed-off-by: Junio C Hamano <gitster@pobox.com>	15 years ago

Author

SHA1

Message

Date

Junio C Hamano

1ee26571e9

traverse_trees(): handle D/F conflict case sanely

traverse_trees() is supposed to call its callback with all the matching
entries from the given trees.  The current algorithm keeps a pointer to
each of the tree being traversed, and feeds the entry with the earliest
name to the callback.

This breaks down if the trees being traversed looks like this:

    A    B
    t-1  t
    t-2  u
    t/a  v

When we are currently looking at an entry "t-1" in tree A, and tree B has
returned "t", feeding "t" from the B and not feeding anything from A, only
because "t-1" sorts later than "t", will miss an entry for a subtree "t"
behind the current entry in tree A.

This introduces extended_entry_extract() helper function that gives what
name is expected from the tree, and implements a mechanism to look-ahead
in the tree object using it, to make sure such a case is handled sanely.
Traversal in tree A in the above example will first return "t" to match
that of B, and then the next request for an entry to A then returns "t-1".

This roughly corresponds to what Linus's "prepare for one-entry lookahead"
wanted to do, but because this does implement look ahead, t6035 and one more
test in t1012 reveal that the approach would not work without adjusting the
side that walks the index in unpack_trees() as well.

Signed-off-by: Junio C Hamano <gitster@pobox.com>

15 years ago

Junio C Hamano

934f930b31

more D/F conflict tests

Before starting to muck with this code, let's expose the current
breakages that we intend to fix.

Signed-off-by: Junio C Hamano <gitster@pobox.com>

15 years ago

2 Commits (1ee26571e97c64bccecfd26d1a1c1c631412a1b7)