1Unicode is used to generate the unicode data in src/corelib/text/.
2
3To update:
4* Find the data (UAX #44, UCD; not the XML version) at
5  ftp://www.unicode.org/Public/zipped/$Version/
6* Unpack the zip file; for each file in data/, replace with the new
7  version; find the *BreakProperty.txt in auxiliary/. (These last are
8  only in the zip, not in the web-space's unpacked versions.)
9* In tst_QTextBoundaryFinder's data/ sub-directory, update its files
10  from the auxiliary/ sub-directory of the UCD data.
11* If needed, add an entry to enum QChar::UnicodeVersion for the new
12  Unicode version
13* In that case, also update main.cpp's initAgeMap and DATA_VERSION_S*
14  to match
15* Build this project. Its binary, unicode, ignores command-line
16  options and assumes it is being run from this directory. When run,
17  it produces lots of output. If it gets as far as updating
18  qunicodetables.cpp the output hopefully doesn't matter.
19* It'll end prematurely with a qFatal() message if it needs updates,
20  either in main.cpp or in QChar:
21  * "unassigned or unhandled age value:" initAgeMap() and
22    QChar::UnicodeVersion;
23  * "Unhandled script property value:" initScriptMap(), QChar::Script,
24    qharfbuzzng.cpp's _qtscript_to_hbscript[] array and
25    qfontconfigdatabase.cpp's specialLanguages.
26  * "unassigned word break class:" enum WordBreakClass,
27    word_break_class_string and initWordBreak();
28* Assertions or other qFatal()s may trigger: if so, study code and
29  understand what's more complicated about this update; talk to folk
30  named in the git logs, maybe push a WIP to gerrit to solicit
31  advice. Some bit-field may need to be expanded, for example. In some
32  cases QChar may need additions to some of its enums.
33* Build with the modified code, fix any compilation issues, make check
34  in suitable directories, including tst_QTextBoundaryFinder.
35* That may have updated qtbase/src/corelib/text/qunicodetables.cpp; if
36  so the update matters; be sure to commit the changes to data/ at the
37  same time and update text/qt_attribution.json to match; use the UCD
38  Revision number, rather than the Unicode standard number, as the
39  Version, for all that qunicodetables.cpp uses the latter (see the
40  'UAX #44, UCD' page linked from https://www.unicode.org/ucd/ for the
41  table with this).
42* If there are enum additions in qchar.h (public API), be sure to also
43  update the documentation in qchar.cpp for each affected enum,
44  respecting the existing ordering.
45* If you don't normally build in the source tree, remember to delete
46  qtbase/.qmake.stash while you're cleaning up.
47
48The script writingSystems.sh generates a list of writing systems,
49ostensibly as a the basis for updating QFontDatabase::WritingSystem
50enum; however, the Release 20 output of it contains many more writing
51systems than are present in that enum, suggesting it has not been run
52in a very long time. Further research needed.
53