_yaml.config_dump() for writing out config

This outputs YAML in a string that is suitable for use in regexps
and string replacements, as well as complete files.  It is therefore
explicitly set up to avoid writing out headers and footers.

fdroidserver/_yaml.py

@@ -38,3 +38,27 @@ yaml = ruamel.yaml.YAML(typ='safe')
 yaml.version = (1, 2)
 
 yaml_dumper = ruamel.yaml.YAML(typ='rt')
+
+
+def config_dump(config, fp=None):
+    """Dump config data in YAML 1.2 format without headers.
+
+    This outputs YAML in a string that is suitable for use in regexps
+    and string replacements, as well as complete files.  It is therefore
+    explicitly set up to avoid writing out headers and footers.
+
+    This is modeled after PyYAML's yaml.dump(), which can dump to a file
+    or return a string.
+
+    https://yaml.dev/doc/ruamel.yaml/example/#Output_of_%60dump()%60_as_a_string
+
+    """
+    dumper = ruamel.yaml.YAML(typ='rt')
+    dumper.default_flow_style = False
+    dumper.explicit_start = False
+    dumper.explicit_end = False
+    if fp is None:
+        with ruamel.yaml.compat.StringIO() as fp:
+            dumper.dump(config, fp)
+            return fp.getvalue()
+    dumper.dump(config, fp)

fdroidserver/common.py

@@ -39,7 +39,6 @@ import sys
 import re
 import ast
 import gzip
-import ruamel.yaml
 import shutil
 import stat
 import subprocess
@@ -67,7 +66,7 @@ from zipfile import ZipFile
 
 import fdroidserver.metadata
 from fdroidserver import _
-from fdroidserver._yaml import yaml, yaml_dumper
+from fdroidserver._yaml import yaml, config_dump
 from fdroidserver.exception import FDroidException, VCSException, NoSubmodulesException, \
     BuildException, VerificationException, MetaDataException
 from .asynchronousfilereader import AsynchronousFileReader
@@ -4230,9 +4229,7 @@ def write_to_config(thisconfig, key, value=None):
             lines[-1] += '\n'
 
     pattern = re.compile(r'^[\s#]*' + key + r':.*\n')
-    with ruamel.yaml.compat.StringIO() as fp:
-        yaml_dumper.dump({key: value}, fp)
-        repl = fp.getvalue()
+    repl = config_dump({key: value})
 
     # If we replaced this line once, we make sure won't be a
     # second instance of this line for this key in the document.

tests/test_common.py

@@ -31,7 +31,7 @@ import fdroidserver.common
 import fdroidserver.metadata
 from .shared_test_code import TmpCwd, mkdtemp
 from fdroidserver.common import ANTIFEATURES_CONFIG_NAME, CATEGORIES_CONFIG_NAME
-from fdroidserver._yaml import yaml, yaml_dumper
+from fdroidserver._yaml import yaml, yaml_dumper, config_dump
 from fdroidserver.exception import FDroidException, VCSException,\
     MetaDataException, VerificationException
 from fdroidserver.looseversion import LooseVersion
@@ -1933,7 +1933,7 @@ class CommonTest(unittest.TestCase):
         os.chdir(self.tmpdir)
         teststr = '/πÇÇ现代通用字-български-عربي1/ö/yml'
         with open(fdroidserver.common.CONFIG_FILE, 'w', encoding='utf-8') as fp:
-            yaml_dumper.dump({'apksigner': teststr}, fp)
+            config_dump({'apksigner': teststr}, fp)
         self.assertTrue(os.path.exists(fdroidserver.common.CONFIG_FILE))
         config = fdroidserver.common.read_config()
         self.assertEqual(teststr, config.get('apksigner'))
@@ -2633,7 +2633,7 @@ class CommonTest(unittest.TestCase):
                 ' -providerClass sun.security.pkcs11.SunPKCS11'
                 ' -providerArg opensc-fdroid.cfg'
             }
-            yaml_dumper.dump(d, fp)
+            config_dump(d, fp)
         config = fdroidserver.common.read_config()
         fdroidserver.common.config = config
         self.assertTrue(isinstance(d['smartcardoptions'], str))

tests/test_lint.py

@@ -12,7 +12,7 @@ from .shared_test_code import mkdtemp
 import fdroidserver.common
 import fdroidserver.lint
 import fdroidserver.metadata
-from fdroidserver._yaml import yaml_dumper
+from fdroidserver._yaml import config_dump
 
 basedir = Path(__file__).parent
 
@@ -365,13 +365,13 @@ class LintTest(unittest.TestCase):
     def test_lint_config_basic_mirrors_yml(self):
         os.chdir(self.testdir)
         with Path('mirrors.yml').open('w') as fp:
-            yaml_dumper.dump([{'url': 'https://example.com/fdroid/repo'}], fp)
+            config_dump([{'url': 'https://example.com/fdroid/repo'}], fp)
         self.assertTrue(fdroidserver.lint.lint_config('mirrors.yml'))
 
     def test_lint_config_mirrors_yml_kenya_countryCode(self):
         os.chdir(self.testdir)
         with Path('mirrors.yml').open('w') as fp:
-            yaml_dumper.dump(
+            config_dump(
                 [{'url': 'https://foo.com/fdroid/repo', 'countryCode': 'KE'}], fp
             )
         self.assertTrue(fdroidserver.lint.lint_config('mirrors.yml'))
@@ -380,7 +380,7 @@ class LintTest(unittest.TestCase):
         """WV is "indeterminately reserved" so it should never be used."""
         os.chdir(self.testdir)
         with Path('mirrors.yml').open('w') as fp:
-            yaml_dumper.dump(
+            config_dump(
                 [{'url': 'https://foo.com/fdroid/repo', 'countryCode': 'WV'}], fp
             )
         self.assertFalse(fdroidserver.lint.lint_config('mirrors.yml'))
@@ -389,7 +389,7 @@ class LintTest(unittest.TestCase):
         """Only ISO 3166-1 alpha 2 are supported"""
         os.chdir(self.testdir)
         with Path('mirrors.yml').open('w') as fp:
-            yaml_dumper.dump(
+            config_dump(
                 [{'url': 'https://de.com/fdroid/repo', 'countryCode': 'DEU'}], fp
             )
         self.assertFalse(fdroidserver.lint.lint_config('mirrors.yml'))
@@ -398,7 +398,7 @@ class LintTest(unittest.TestCase):
         """WV is "indeterminately reserved" so it should never be used."""
         os.chdir(self.testdir)
         with Path('mirrors.yml').open('w') as fp:
-            yaml_dumper.dump(
+            config_dump(
                 [
                     {'url': 'https://bar.com/fdroid/repo', 'countryCode': 'BA'},
                     {'url': 'https://foo.com/fdroid/repo', 'countryCode': 'FO'},