merge_configs: Add lstrip_blocks

Closes-Bug: #2164718

Change-Id: If5b7f30d2467b61c3578d09992faf446b5d25f4e
Signed-off-by: Michal Nasiadka <mnasiadka@gmail.com>
(cherry picked from commit 0f4da209da6fa39739ffc7b7fb1a69dc967734b7)

4 files changed, 83 insertions, 4 deletions

diff --git a/ansible/action_plugins/merge_configs.py b/ansible/action_plugins/merge_configs.py
index 67a7da1cd..09dc1d04e 100644
--- a/ansible/action_plugins/merge_configs.py
+++ b/ansible/action_plugins/merge_configs.py
@@ -169,9 +169,12 @@ class ActionModule(action.ActionBase):
                 os.path.join(self._loader._basedir, 'templates'),
                 os.path.dirname(source),
             ]
-            self._templar.environment.loader.searchpath = searchpath
+            templar = self._templar.copy_with_new_env(searchpath=searchpath)
 
-            result = self._templar.template(template_data)
+            # lstrip_blocks avoids Jinja2 block tags (e.g. {% if %}) leaving
+            # behind leading whitespace that glues adjacent lines together.
+            result = templar.template(
+                template_data, overrides=dict(lstrip_blocks=True))
             fakefile = StringIO(result)
             config.parse(fakefile)
             fakefile.close()
diff --git a/ansible/action_plugins/merge_yaml.py b/ansible/action_plugins/merge_yaml.py
index d2c15eb70..f3ba8597b 100644
--- a/ansible/action_plugins/merge_yaml.py
+++ b/ansible/action_plugins/merge_yaml.py
@@ -109,9 +109,12 @@ class ActionModule(action.ActionBase):
                 os.path.join(self._loader._basedir, 'templates'),
                 os.path.dirname(source),
             ]
-            self._templar.environment.loader.searchpath = searchpath
+            templar = self._templar.copy_with_new_env(searchpath=searchpath)
 
-            template_data = self._templar.template(template_data)
+            # lstrip_blocks avoids Jinja2 block tags (e.g. {% if %}) leaving
+            # behind leading whitespace that glues adjacent lines together.
+            template_data = templar.template(
+                template_data, overrides=dict(lstrip_blocks=True))
             result = yaml.safe_load(template_data)
         return result or {}
 
diff --git a/tests/test_merge_config.py b/tests/test_merge_config.py
index d64b2ae6b..de2c98281 100644
--- a/tests/test_merge_config.py
+++ b/tests/test_merge_config.py
@@ -15,8 +15,12 @@
 
 from importlib.machinery import SourceFileLoader
 import os
+import tempfile
 
 from io import StringIO
+
+from ansible.parsing.dataloader import DataLoader
+from ansible.template import Templar
 from oslotest import base
 
 
@@ -211,3 +215,40 @@ class OverrideConfigParserTest(base.BaseTestCase):
         parser.write(output)
         self.assertEqual(TESTC_NO_WHITESPACE, output.getvalue())
         output.close()
+
+    def test_read_config_lstrip_blocks(self):
+        # An indented Jinja2 block tag on its own line must not leak its
+        # leading whitespace into the following line, or the line gets
+        # parsed as a continuation of the previous key's value instead of
+        # a new key.
+        content = (
+            "[DEFAULT]\n"
+            "key1 = value1\n"
+            "  {% if true %}\n"
+            "key2 = value2\n"
+            "  {% endif %}\n"
+            "key3 = value3\n"
+        )
+        with tempfile.TemporaryDirectory() as tmpdir:
+            source = os.path.join(tmpdir, 'source.conf')
+            with open(source, 'w') as f:
+                f.write(content)
+
+            loader = DataLoader()
+            loader.set_basedir(tmpdir)
+            action = object.__new__(merge_configs.ActionModule)
+            action._loader = loader
+            action._templar = Templar(loader=loader)
+
+            config = merge_configs.OverrideConfigParser()
+            action.read_config(source, config)
+
+        output = StringIO()
+        config.write(output)
+        self.assertEqual(
+            "[DEFAULT]\n"
+            "key1 = value1\n"
+            "key2 = value2\n"
+            "key3 = value3\n\n",
+            output.getvalue())
+        output.close()
diff --git a/tests/test_merge_yaml.py b/tests/test_merge_yaml.py
index d6b74ae77..35de91d2c 100644
--- a/tests/test_merge_yaml.py
+++ b/tests/test_merge_yaml.py
@@ -15,8 +15,11 @@
 
 from importlib.machinery import SourceFileLoader
 import os
+import tempfile
 
 from ansible.errors import AnsibleModuleError
+from ansible.parsing.dataloader import DataLoader
+from ansible.template import Templar
 from oslotest import base
 
 PROJECT_DIR = os.path.abspath(os.path.join(os. path.dirname(__file__), '../'))
@@ -174,3 +177,32 @@ class MergeYamlConfigTest(base.BaseTestCase):
         with self.assertRaisesRegex(AnsibleModuleError, "Failure merging key"):
             merge_yaml.Utils.update_nested_conf(
                 initial_conf, extension, extend_lists=True)
+
+    def test_read_config_lstrip_blocks(self):
+        # An indented Jinja2 block tag on its own line must not leak its
+        # leading whitespace into the following line, or the resulting
+        # YAML indentation becomes inconsistent with its siblings.
+        content = (
+            "foo:\n"
+            "  bar: baz\n"
+            "  {% if true %}\n"
+            "  extra: value\n"
+            "  {% endif %}\n"
+            "  qux: quux\n"
+        )
+        with tempfile.TemporaryDirectory() as tmpdir:
+            source = os.path.join(tmpdir, 'source.yml')
+            with open(source, 'w') as f:
+                f.write(content)
+
+            loader = DataLoader()
+            loader.set_basedir(tmpdir)
+            action = object.__new__(merge_yaml.ActionModule)
+            action._loader = loader
+            action._templar = Templar(loader=loader)
+
+            result = action.read_config(source)
+
+        self.assertEqual(
+            {'foo': {'bar': 'baz', 'extra': 'value', 'qux': 'quux'}},
+            result)