comparison mercurial/merge.py @ 9716:ea8c207a0f78

update: add comments and test cases for updating across branches

Add comment to merge.py:update() showing various cases of 'hg update': to a
descendant, crossing named branches, and crossing branches within a named
branch; with no option, -c or -C; with or without uncommitted changes; and
with or without a specific revision. Add tests for all of these cases.

9715:f0e99a2eac76

def update(repo, node, branchmerge, force, partial):
    """
    Perform a merge between the working directory and the given node

    branchmerge = whether to merge between branches
    force = whether to force branch merging or file overwriting
    partial = a function to filter file lists (dirstate not updated)
    """

    wlock = repo.wlock()
    try:
        wc = repo[None]

9716:ea8c207a0f78

def update(repo, node, branchmerge, force, partial):
    """
    Perform a merge between the working directory and the given node

    node = the node to update to, or None if unspecified
    branchmerge = whether to merge between branches
    force = whether to force branch merging or file overwriting
    partial = a function to filter file lists (dirstate not updated)

    The table below shows all the behaviors of the update command
    given the -c and -C or no options, whether the working directory
    is dirty, whether a revision is specified, and the relationship of
    the parent rev to the target rev (linear, on the same named
    branch, or on another named branch).

    This logic is tested by test-update-branches.

    -c  -C  dirty  rev  |  linear   same  cross
     n   n    n     n   |    ok     (1)     x
     n   n    n     y   |    ok     (1)    ok
     n   n    y     *   |   merge   (2)    (3)
     n   y    *     *   |    ---  discard  ---
     y   n    y     *   |    ---    (4)    ---
     y   n    n     *   |    ---    ok     ---
     y   y    *     *   |    ---    (5)    ---

    x = can't happen
    * = don't-care
    1 = abort: crosses branches (use 'hg merge' or 'hg update -C')
    2 = abort: crosses branches (use 'hg merge' or 'hg update -C'
                 to discard changes)
    3 = abort: crosses named branches (use 'hg update -C' to
                 discard changes)
    4 = abort: uncommitted local changes
    5 = incompatible options (checked in commands.py)
    """

    wlock = repo.wlock()
    try:
        wc = repo[None]