1 FILE CONDITIONS

     2 

     3 Read configuring-access before you read this.

     4 

     5 mercurial-server supports file and branch conditions, which restrict an

     6 operation depending on what files it modifies and what branch the work is

     7 on. However, the way these conditions work is subtle and can be

     8 counterintuitive - if you want to keep things simple, stick to user and

     9 repo conditions, and then things are likely to work the way you would

    10 expect.

    11 

    12 File and branch conditions are added to the conditions against which a rule

    13 matches, just like user and repo conditions; they have this form:

    14 

    15     file=<globpattern> - file in the repo

    16     branch=<globpattern> - name of the branch

    17 

    18 However, in order to understand what effect adding these conditions will

    19 have, it helps to understand how and when these rules are applied.

    20 

    21 The rules file is used to make four decisions:

    22 

    23 - Whether to allow a repository to be created

    24 - Whether to allow access to a repository

    25 - Whether to allow a changeset on a particular branch at all

    26 - Whether to allow a changeset to change a particular file

    27 

    28 When the first two of these decisions are being made, nothing is known

    29 about what files might be changed, and so all file conditions automatically

    30 succeed for the purpose of such decisions. This means that doing tricky

    31 things with file conditions can have counterintuitive consequences:

    32 

    33 - You cannot limit read access to a subset of a repository with a "read"

    34 rule and a file condition: any user who has access to a repository can read

    35 all of it and its full history. Such a rule can only have the effect of

    36 masking a later "write" rule, as in this example:

    37 

    38    read repo=specialrepo file=dontwritethis

    39    write repo=specialrepo

    40 

    41 allows all users to read specialrepo, and to write to all files *except*

    42 that any changeset which writes to "dontwritethis" will be rejected.

    43 

    44 - For similar reasons, don't give "init" rules file conditions.

    45 

    46 - Don't try to deny write access to a particular file on a particular

    47 branch - a developer can write to the file on another branch and then merge

    48 it in. Either deny all writes to the branch from that user, or allow them

    49 to write to all the files they can write to on any branch. In other words,

    50 something like this will have the intended effect:

    51 

    52   write user=docs/* branch=docs file=docs/*

    53 

    54 But something like this will not have the intended effect; it will

    55 effectively allow these users to write to any file on any branch, by

    56 writing it to "docs" first:

    57 

    58   write user=docs/* branch=docs

    59   write user=docs/* file=docs/*

    60   read user=docs/*

    61 

    62