[damned-lies] Fixes #142 - Remove "do not translate" strings from pot files

[Claude Paroz <claudep src gnome org>]

commit b858920afd1748e413b2c04051e02c78279c4e25
Author: Claude Paroz <claude 2xlibre net>
Date:   Fri Mar 22 20:55:36 2019 +0100

    Fixes #142 - Remove "do not translate" strings from pot files

 stats/models.py      |  3 +++
 stats/tests/tests.py |  8 ++++++++
 stats/utils.py       | 23 +++++++++++++++++++++++
 3 files changed, 34 insertions(+)
---
diff --git a/stats/models.py b/stats/models.py
index f0b01339..50c27fa5 100644
--- a/stats/models.py
+++ b/stats/models.py
@@ -785,6 +785,9 @@ class Domain(models.Model):
                         if file_.match('*.pot'):
                             potfile = file_
                             break
+            elif pot_method == 'gettext':
+                # Filter out strings NOT to be translated, typically icon file names.
+                exclude_untrans_messages(potfile)
 
         if errors:
             return "", errors
diff --git a/stats/tests/tests.py b/stats/tests/tests.py
index e92f15ae..eaf8c70f 100644
--- a/stats/tests/tests.py
+++ b/stats/tests/tests.py
@@ -843,6 +843,14 @@ class UtilsTests(TestModuleBase):
         utils.insert_locale_in_linguas(linguas_path, 'xx')
         self.assertTrue(linguas_path.read_text().endswith('xx\n'))
 
+    def test_exclude_messages_from_potfile(self):
+        pot_file = Path(__file__).parent / 'donottranslate.pot'
+        with tempfile.NamedTemporaryFile(suffix='.pot') as temppot:
+            shutil.copyfile(str(pot_file), temppot.name)
+            utils.exclude_untrans_messages(temppot.name)
+            stats = utils.po_file_stats(Path(temppot.name))
+        self.assertEqual(stats['untranslated'], 2)
+
     @test_scratchdir
     def test_po_grep(self):
         # Take it.po, because desktop.in.h strings are not yet translated
diff --git a/stats/utils.py b/stats/utils.py
index 69db65e5..7023d464 100644
--- a/stats/utils.py
+++ b/stats/utils.py
@@ -699,6 +699,7 @@ def check_identical_figures(fig_stats, base_path, lang):
                 errors.append(("warn-ext", "Figures should not be copied when identical to original (%s)." % 
trans_path))
     return errors
 
+
 def add_custom_header(po_path, header, value):
     """ Add a custom po file header """
     grep_cmd = """grep "%s" %s""" % (header, po_path)
@@ -715,6 +716,28 @@ def add_custom_header(po_path, header, value):
         cmd = '''sed -i '/^\"%s/ c\\"%s: %s\\\\n"' %s''' % (header, header, value, po_path)
         (stat, out, err) = run_shell_command(cmd)
 
+
+def exclude_untrans_messages(potfile):
+    """Exclude translatable strings matching some translator comments."""
+    exclude_message = 'translators: do not translate or transliterate this text'
+    # Grep first the file to see if the message is in the file.
+    status, _, _ = run_shell_command(['grep', '-i', exclude_message, potfile])
+    if status != STATUS_OK:
+        return
+
+    with open(str(potfile), 'r+') as fh:
+        lines = fh.readlines()
+        fh.seek(0)
+        skip_unit = False
+        for line in lines:
+            if not exclude_message in line.lower() and not skip_unit:
+                fh.write(line)
+            else:
+                # A blank line is resetting skip_unit
+                skip_unit = line != '\n'
+        fh.truncate()
+
+
 def is_po_reduced(file_path):
     status, output, errs = run_shell_command(['grep', 'X-DamnedLies-Scope: partial', file_path])
     return (status == 0)