Fix zombie files in merge # HG changeset patch # User maf46@burn.cl.cam.ac.uk # Node ID 57667c9b93a5a743e4629d15a0e6bd76699130c3 # Parent d2994b5298fb20f87dc1d4747635b280db3c0526 Fix zombie files in merge Keir Fraser observed the following: > I made a small test case that illustrates the bug in merging changesets > with 'hg remove's in them: > > 1. Create a repository A containing files foo & bar. > 2. Create clone called B. > 3. A removes file bar, and commits this removal. > 4. B edits file foo, and commits this edit. > > Now, if B: > # hg pull ../A; hg update -m; hg commit > Then bar remains deleted. > > If A: > # hg pull ../B; hg update -m; hg commit > Then bar is resurrected! > > It looks as though, when you merge across a branch, any deletions in > your own branch are forgotten. > ... > Fixing this is a must, as zombie files are a real pain. :-) Keir later patched our local copy of hg as shown below, which fixes the problem. I've also enclosed a test which captures the test Keir outlined... Files deleted on a branch should not automatically reappear in a merge Patch notes: 1. The first chunk does not change behaviour, but cleans up the code to more closely match check of 'force' in the second chunk. I think it makes the code clearer. 2. The second chunk fixes two bugs -- i. If we choose to keep a remotely-changed locally-deleted file, then we need to 'get' that file. If we choose to delete it then no action need be taken (it is already deleted in the working manifest). Without this fix, choosing to delete would get a Python traceback. ii. The test for whether the file was remotely-created is insufficient. It is only true if f is not in the common ancestor. Otherwise the file was deleted locally, and should remain deleted. (this is the most important fix!) Index: hg/tests/test-merge6 ===================================================================

     1

                    Mercurial      git                     BK (*)

     2

storage             revlog delta   compressed revisions    SCCS weave

     3

storage naming      by filename    by revision hash        by filename

     4

merge               file DAGs      changeset DAG           file DAGs?

     5

consistency         SHA1           SHA1                    CRC

     6

signable?           yes            yes                     no       

     7

     8

retrieve file tip   O(1)           O(1)                    O(revs)

     9

add rev             O(1)           O(1)                    O(revs)

    10

find prev file rev  O(1)           O(changesets)           O(revs)

    11

annotate file       O(revs)        O(changesets)           O(revs)

    12

find file changeset O(1)           O(changesets)           ?

    13

    14

checkout            O(files)       O(files)                O(revs)?

    15

commit              O(changes)     O(changes)              ?

    16

                    6 patches/s    6 patches/s             slow

    17

diff working dir    O(changes)     O(changes)              ?

    18

                    < 1s           < 1s                    ?

    19

tree diff revs      O(changes)     O(changes)              ?

    20

                    < 1s           < 1s                    ?

    21

hardlink clone      O(files)       O(revisions)            O(files)

    22

    23

find remote csets   O(log new)     rsync: O(revisions)     ?

    24

                                   git-http: O(changesets)

    25

pull remote csets   O(patch)       O(modified files)       O(patch)

    26

    27

repo growth         O(patch)       O(revisions)            O(patch)

    28

 kernel history     300M           3.5G?                   250M?

    29

lines of code       2500           6500 (+ cogito)         ??

    30

    31

* I've never used BK so this is just guesses