1Contributing to the tz code and data
2
3The time zone database is by no means authoritative: governments
4change timekeeping rules erratically and sometimes with little
5warning, the data entries do not cover all of civil time before
61970, and undoubtedly errors remain in the code and data.  Feel
7free to fill gaps or fix mistakes, and please email improvements
8to tz@iana.org for use in the future.
9
10To email small changes, please run a POSIX shell command like
11'diff -u old/europe new/europe >myfix.patch', and attach
12myfix.patch to the email.
13
14For more-elaborate changes, please read the Theory file and browse
15the mailing list archives <http://mm.icann.org/pipermail/tz/> for
16examples of patches that tend to work well.  Ideally, additions to
17data should contain commentary citing reliable sources as
18justification.
19
20Please submit changes against either the latest release in
21<ftp://ftp.iana.org/tz/> or the master branch of the experimental
22Git repository.  If you use Git the following workflow may be helpful:
23
24  * Copy the experimental repository.
25
26      git clone https://github.com/eggert/tz.git
27      cd tz
28
29  * Get current with the master branch.
30
31      git checkout master
32      git pull
33
34  * Switch to a new branch for the changes.  Choose a different
35    branch name for each change set.
36
37      git checkout -b mybranch
38
39  * Edit source files.  Include commentary that justifies the
40    changes by citing reliable sources.
41
42  * Debug the changes, e.g.:
43
44      make check
45      make install
46      ./zdump -v America/Los_Angeles
47
48  * For each separable change, commit it in the new branch, e.g.:
49
50      git add northamerica
51      git commit
52
53    See recent 'git log' output for the commit-message style.
54
55  * Create patch files 0001-*, 0002-*, ...
56
57      git format-patch master
58
59  * After reviewing the patch files, send the patches to tz@iana.org
60    for others to review.
61
62      git send-email master
63
64  * Start anew by getting current with the master branch again
65    (the second step above).
66
67Please do not create issues or pull requests on GitHub, as the
68proper procedure for proposing and distributing patches is via
69email as illustrated above.
70
71-----
72
73This file is in the public domain.
74