[tz] [PATCH 0/5] Simplifying Link line maintenance

Paul Eggert eggert at cs.ucla.edu
Mon Sep 26 00:32:16 UTC 2022

Although TZDB currently puts most Link lines in the ‘backward’ file,
some Link lines reside in the continental files ‘africa’,
‘antarctica’, etc., with little rhyme or reason as to which lines are
in ‘backward’ and which line are in a continental file.  This is
confusing and makes maintenance a bit more difficult.

This proposed series of patches aims to regularize this by putting the
Link lines into ‘backward’, except that to work around a TZUpdater bug
the GMT Link line is in ‘backward’ only when using vanguard form.

As part of these patches, the Link lines in ‘backward’ are organized
into sections that better explain the reason for each Link line.
Also, comments are added to document shortcut Link lines, that is,
Link lines reworded to reference the target rather than the source of
another Link line.  Furthermore, the Makefile is augmented to check
Link lines more carefully.

The overall effect of this patch is to shrink TZDB’s source code and
make maintenance simpler and more robust, without affecting data
except for users who are purposely bleeding-edge by omitting all
backward-compatibility links.

Because these patches are nontrivial I have not installed them in the
development repository, and there is no rush.  Comments welcome as

Paul Eggert (5):
  Move a few links to ‘backward’
  Move most remaining links to ‘backward’
  Reorder 'backward’
  Improve checking for shortcut links
  Coalesce some commentary

 Makefile       |   6 +-
 NEWS           |  17 +++
 africa         | 213 ++++++++++--------------------------
 antarctica     |   2 +-
 asia           |  69 ++++--------
 australasia    |  46 +++-----
 backward       | 288 +++++++++++++++++++++++++++++++++++++++----------
 checklinks.awk |  17 +++
 etcetera       |  17 ++-
 europe         | 202 ++++++++++++----------------------
 northamerica   |  86 ++++-----------
 southamerica   |  15 ---
 theory.html    |   1 +
 zdump.c        |   4 +-
 ziguard.awk    |  14 +++
 15 files changed, 472 insertions(+), 525 deletions(-)


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