i18n: make GETTEXT_POISON a runtime option
[git/git.git] / po / README
1 Core GIT Translations
2 =====================
3
4 This directory holds the translations for the core of Git. This document
5 describes how you can contribute to the effort of enhancing the language
6 coverage and maintaining the translation.
7
8 The localization (l10n) coordinator, Jiang Xin <worldhello.net@gmail.com>,
9 coordinates our localization effort in the l10 coordinator repository:
10
11 https://github.com/git-l10n/git-po/
12
13 The two character language translation codes are defined by ISO_639-1, as
14 stated in the gettext(1) full manual, appendix A.1, Usual Language Codes.
15
16
17 Contributing to an existing translation
18 ---------------------------------------
19 As a contributor for a language XX, you should first check TEAMS file in
20 this directory to see whether a dedicated repository for your language XX
21 exists. Fork the dedicated repository and start to work if it exists.
22
23 Sometime, contributors may find that the translations of their Git
24 distributions are quite different with the translations of the
25 corresponding version from Git official. This is because some Git
26 distributions (such as from Ubuntu, etc.) have their own l10n workflow.
27 For this case, wrong translations should be reported and fixed through
28 their workflows.
29
30
31 Creating a new language translation
32 -----------------------------------
33 If you are the first contributor for the language XX, please fork this
34 repository, prepare and/or update the translated message file po/XX.po
35 (described later), and ask the l10n coordinator to pull your work.
36
37 If there are multiple contributors for the same language, please first
38 coordinate among yourselves and nominate the team leader for your
39 language, so that the l10n coordinator only needs to interact with one
40 person per language.
41
42
43 Translation Process Flow
44 ------------------------
45 The overall data-flow looks like this:
46
47 +-------------------+ +------------------+
48 | Git source code | ---(1)---> | L10n coordinator |
49 | repository | <---(4)--- | repository |
50 +-------------------+ +------------------+
51 | ^
52 (2) (3)
53 V |
54 +------------------+
55 | Language Team XX |
56 +------------------+
57
58 * Translatable strings are marked in the source file.
59 * L10n coordinator pulls from the source (1)
60 * L10n coordinator updates the message template po/git.pot
61 * Language team pulls from L10n coordinator (2)
62 * Language team updates the message file po/XX.po
63 * L10n coordinator pulls from Language team (3)
64 * L10n coordinator asks the result to be pulled (4).
65
66
67 Maintaining the po/git.pot file
68 -------------------------------
69
70 (This is done by the l10n coordinator).
71
72 The po/git.pot file contains a message catalog extracted from Git's
73 sources. The l10n coordinator maintains it by adding new translations with
74 msginit(1), or update existing ones with msgmerge(1). In order to update
75 the Git sources to extract the messages from, the l10n coordinator is
76 expected to pull from the main git repository at strategic point in
77 history (e.g. when a major release and release candidates are tagged),
78 and then run "make pot" at the top-level directory.
79
80 Language contributors use this file to prepare translations for their
81 language, but they are not expected to modify it.
82
83
84 Initializing a XX.po file
85 -------------------------
86
87 (This is done by the language teams).
88
89 If your language XX does not have translated message file po/XX.po yet,
90 you add a translation for the first time by running:
91
92 msginit --locale=XX
93
94 in the po/ directory, where XX is the locale, e.g. "de", "is", "pt_BR",
95 "zh_CN", etc.
96
97 Then edit the automatically generated copyright info in your new XX.po
98 to be correct, e.g. for Icelandic:
99
100 @@ -1,6 +1,6 @@
101 -# Icelandic translations for PACKAGE package.
102 -# Copyright (C) 2010 THE PACKAGE'S COPYRIGHT HOLDER
103 -# This file is distributed under the same license as the PACKAGE package.
104 +# Icelandic translations for Git.
105 +# Copyright (C) 2010 Ævar Arnfjörð Bjarmason <avarab@gmail.com>
106 +# This file is distributed under the same license as the Git package.
107 # Ævar Arnfjörð Bjarmason <avarab@gmail.com>, 2010.
108
109 And change references to PACKAGE VERSION in the PO Header Entry to
110 just "Git":
111
112 perl -pi -e 's/(?<="Project-Id-Version: )PACKAGE VERSION/Git/' XX.po
113
114 Once you are done testing the translation (see below), commit the result
115 and ask the l10n coordinator to pull from you.
116
117
118 Updating a XX.po file
119 ---------------------
120
121 (This is done by the language teams).
122
123 If you are replacing translation strings in an existing XX.po file to
124 improve the translation, just edit the file.
125
126 If there's an existing XX.po file for your language, but the repository
127 of the l10n coordinator has newer po/git.pot file, you would need to first
128 pull from the l10n coordinator (see the beginning of this document for its
129 URL), and then update the existing translation by running:
130
131 msgmerge --add-location --backup=off -U XX.po git.pot
132
133 in the po/ directory, where XX.po is the file you want to update.
134
135 Once you are done testing the translation (see below), commit the result
136 and ask the l10n coordinator to pull from you.
137
138
139 Testing your changes
140 --------------------
141
142 (This is done by the language teams, after creating or updating XX.po file).
143
144 Before you submit your changes go back to the top-level and do:
145
146 make
147
148 On systems with GNU gettext (i.e. not Solaris) this will compile your
149 changed PO file with `msgfmt --check`, the --check option flags many
150 common errors, e.g. missing printf format strings, or translated
151 messages that deviate from the originals in whether they begin/end
152 with a newline or not.
153
154
155 Marking strings for translation
156 -------------------------------
157
158 (This is done by the core developers).
159
160 Before strings can be translated they first have to be marked for
161 translation.
162
163 Git uses an internationalization interface that wraps the system's
164 gettext library, so most of the advice in your gettext documentation
165 (on GNU systems `info gettext` in a terminal) applies.
166
167 General advice:
168
169 - Don't mark everything for translation, only strings which will be
170 read by humans (the porcelain interface) should be translated.
171
172 The output from Git's plumbing utilities will primarily be read by
173 programs and would break scripts under non-C locales if it was
174 translated. Plumbing strings should not be translated, since
175 they're part of Git's API.
176
177 - Adjust the strings so that they're easy to translate. Most of the
178 advice in `info '(gettext)Preparing Strings'` applies here.
179
180 - If something is unclear or ambiguous you can use a "TRANSLATORS"
181 comment to tell the translators what to make of it. These will be
182 extracted by xgettext(1) and put in the po/*.po files, e.g. from
183 git-am.sh:
184
185 # TRANSLATORS: Make sure to include [y], [n], [e], [v] and [a]
186 # in your translation. The program will only accept English
187 # input at this point.
188 gettext "Apply? [y]es/[n]o/[e]dit/[v]iew patch/[a]ccept all "
189
190 Or in C, from builtin/revert.c:
191
192 /* TRANSLATORS: %s will be "revert" or "cherry-pick" */
193 die(_("%s: Unable to write new index file"), action_name(opts));
194
195 We provide wrappers for C, Shell and Perl programs. Here's how they're
196 used:
197
198 C:
199
200 - Include builtin.h at the top, it'll pull in gettext.h, which
201 defines the gettext interface. Consult with the list if you need to
202 use gettext.h directly.
203
204 - The C interface is a subset of the normal GNU gettext
205 interface. We currently export these functions:
206
207 - _()
208
209 Mark and translate a string. E.g.:
210
211 printf(_("HEAD is now at %s"), hex);
212
213 - Q_()
214
215 Mark and translate a plural string. E.g.:
216
217 printf(Q_("%d commit", "%d commits", number_of_commits));
218
219 This is just a wrapper for the ngettext() function.
220
221 - N_()
222
223 A no-op pass-through macro for marking strings inside static
224 initializations, e.g.:
225
226 static const char *reset_type_names[] = {
227 N_("mixed"), N_("soft"), N_("hard"), N_("merge"), N_("keep"), NULL
228 };
229
230 And then, later:
231
232 die(_("%s reset is not allowed in a bare repository"),
233 _(reset_type_names[reset_type]));
234
235 Here _() couldn't have statically determined what the translation
236 string will be, but since it was already marked for translation
237 with N_() the look-up in the message catalog will succeed.
238
239 Shell:
240
241 - The Git gettext shell interface is just a wrapper for
242 gettext.sh. Import it right after git-sh-setup like this:
243
244 . git-sh-setup
245 . git-sh-i18n
246
247 And then use the gettext or eval_gettext functions:
248
249 # For constant interface messages:
250 gettext "A message for the user"; echo
251
252 # To interpolate variables:
253 details="oh noes"
254 eval_gettext "An error occurred: \$details"; echo
255
256 In addition we have wrappers for messages that end with a trailing
257 newline. I.e. you could write the above as:
258
259 # For constant interface messages:
260 gettextln "A message for the user"
261
262 # To interpolate variables:
263 details="oh noes"
264 eval_gettextln "An error occurred: \$details"
265
266 More documentation about the interface is available in the GNU info
267 page: `info '(gettext)sh'`. Looking at git-am.sh (the first shell
268 command to be translated) for examples is also useful:
269
270 git log --reverse -p --grep=i18n git-am.sh
271
272 Perl:
273
274 - The Git::I18N module provides a limited subset of the
275 Locale::Messages functionality, e.g.:
276
277 use Git::I18N;
278 print __("Welcome to Git!\n");
279 printf __("The following error occurred: %s\n"), $error;
280
281 Run `perldoc perl/Git/I18N.pm` for more info.
282
283
284 Testing marked strings
285 ----------------------
286
287 Even if you've correctly marked porcelain strings for translation
288 something in the test suite might still depend on the US English
289 version of the strings, e.g. to grep some error message or other
290 output.
291
292 To smoke out issues like these, Git tested with a translation mode that
293 emits gibberish on every call to gettext. To use it run the test suite
294 with it, e.g.:
295
296 cd t && GIT_TEST_GETTEXT_POISON=YesPlease prove -j 9 ./t[0-9]*.sh
297
298 If tests break with it you should inspect them manually and see if
299 what you're translating is sane, i.e. that you're not translating
300 plumbing output.
301
302 If not you should replace calls to grep with test_i18ngrep, or
303 test_cmp calls with test_i18ncmp. If that's not enough you can skip
304 the whole test by making it depend on the C_LOCALE_OUTPUT
305 prerequisite. See existing test files with this prerequisite for
306 examples.