Normalize rendered template output for pre-commit

posit-bakery/posit_bakery/config/config.py

@@ -25,7 +25,7 @@
 from posit_bakery.config.repository import Repository
 from posit_bakery.config.shared import BakeryPathMixin, BakeryYAMLModel
 from posit_bakery.config.templating import TPL_CONTAINERFILE, TPL_BAKERY_CONFIG_YAML
-from posit_bakery.config.templating.render import jinja2_env
+from posit_bakery.config.templating.render import jinja2_env, normalize_rendered_output
 from posit_bakery.config.image.parsed_version import ParsedVersion
 from posit_bakery.config.image.posit_product.const import ReleaseStreamEnum
 from posit_bakery.const import DEFAULT_BASE_IMAGE, DevVersionInclusionEnum, MatrixVersionInclusionEnum
@@ -197,7 +197,7 @@ def create_image_files_template(image_path: Path, image_name: str, base_tag: str
             tpl = jinja2_env().from_string(TPL_CONTAINERFILE)
             rendered = tpl.render(image_name=image_name, base_tag=base_tag)
             with open(containerfile_path, "w") as f:
-                f.write(rendered)
+                f.write(normalize_rendered_output(rendered))
 
         image_test_path = image_template_path / "test"
         if not image_test_path.is_dir():
@@ -417,14 +417,13 @@ def new(base_path: str | Path | os.PathLike) -> None:
         tpl = jinja2_env(loader=jinja2.FileSystemLoader(config_file.parent)).from_string(TPL_BAKERY_CONFIG_YAML)
         rendered = tpl.render(repo_url=util.try_get_repo_url(base_path))
         with open(config_file, "w") as f:
-            f.write(rendered)
+            f.write(normalize_rendered_output(rendered))
 
     def write(self) -> None:
         """Write the bakery config to the config file."""
         stream = io.StringIO()
         self.yaml.dump(self._config_yaml, stream)
-        text = re.sub(r"[ \t]+$", "", stream.getvalue(), flags=re.MULTILINE)
-        self.config_file.write_text(text)
+        self.config_file.write_text(normalize_rendered_output(stream.getvalue()))
 
     def _get_image_index(self, image_name: str) -> int:
         """Returns the index of the image with the given name in the config.

posit-bakery/posit_bakery/config/image/matrix.py

@@ -24,6 +24,7 @@
 from posit_bakery.config.registry import BaseRegistry, Registry
 from posit_bakery.config.shared import BakeryPathMixin, BakeryYAMLModel
 from posit_bakery.config.templating import jinja2_env
+from posit_bakery.config.templating.render import normalize_rendered_output
 from posit_bakery.const import JINJA2_TEMPLATE_EXTENSIONS
 from posit_bakery.error import BakeryFileError, BakeryRenderError, BakeryTemplateError, BakeryRenderErrorGroup
 from .variant import ImageVariant
@@ -571,11 +572,6 @@ def render_files(self, variants: list[ImageVariant] | None = None, regex_filters
                     )
                     continue
 
-                # Enable trim_blocks for Containerfile templates
-                render_kwargs = {}
-                if tpl_rel_path.startswith("Containerfile"):
-                    render_kwargs["trim_blocks"] = True
-
                 # If variants are specified, render Containerfile for each variant
                 if tpl_rel_path.startswith("Containerfile") and variants:
                     containerfile_base_name = tpl_rel_path.removesuffix(".jinja2")
@@ -592,7 +588,7 @@ def render_files(self, variants: list[ImageVariant] | None = None, regex_filters
                         template_values = self.generate_template_values(variant, containerfile_os)
                         containerfile: Path = self.path / f"{containerfile_base_name}.{variant.extension}"
                         try:
-                            rendered = tpl.render(**template_values, **render_kwargs)
+                            rendered = tpl.render(**template_values)
                         except (jinja2.TemplateError, BakeryTemplateError) as e:
                             log.error(
                                 f"Failed to render template [bold]{tpl_rel_path}[/] for image '{self.parent.name}' "
@@ -612,7 +608,7 @@ def render_files(self, variants: list[ImageVariant] | None = None, regex_filters
                             continue
                         log.debug(f"[bright_black]Rendering [bold]{containerfile}")
                         copy2(tpl_full_path, containerfile)
-                        containerfile.write_text(rendered)
+                        containerfile.write_text(normalize_rendered_output(rendered))
 
                 # Render other templates once
                 else:
@@ -621,7 +617,7 @@ def render_files(self, variants: list[ImageVariant] | None = None, regex_filters
                     output_file.parent.mkdir(parents=True, exist_ok=True)
                     template_values = self.generate_template_values()
                     try:
-                        rendered = tpl.render(**template_values, **render_kwargs)
+                        rendered = tpl.render(**template_values)
                     except (jinja2.TemplateError, BakeryTemplateError) as e:
                         log.error(
                             f"Failed to render template [bold]{tpl_rel_path}[/] for image '{self.parent.name}' matrix"
@@ -639,7 +635,7 @@ def render_files(self, variants: list[ImageVariant] | None = None, regex_filters
                         continue
                     log.debug(f"[bright_black]Rendering [bold]{output_file}")
                     copy2(tpl_full_path, output_file)
-                    output_file.write_text(rendered)
+                    output_file.write_text(normalize_rendered_output(rendered))
 
         if exceptions:
             if len(exceptions) == 1:

posit-bakery/posit_bakery/config/image/version.py

@@ -21,6 +21,7 @@
 from .variant import ImageVariant
 from .version_os import ImageVersionOS
 from ..templating import jinja2_env
+from ..templating.render import normalize_rendered_output
 from ...error import BakeryFileError, BakeryRenderError, BakeryTemplateError, BakeryRenderErrorGroup
 
 log = logging.getLogger(__name__)
@@ -468,11 +469,6 @@ def render_files(
                     )
                     continue
 
-                # Enable trim_blocks for Containerfile templates
-                render_kwargs = {}
-                if tpl_rel_path.startswith("Containerfile"):
-                    render_kwargs["trim_blocks"] = True
-
                 # If variants are specified, render Containerfile for each variant
                 if tpl_rel_path.startswith("Containerfile") and variants:
                     containerfile_base_name = tpl_rel_path.removesuffix(".jinja2")
@@ -497,7 +493,7 @@ def render_files(
                         template_values = self.generate_template_values(variant, containerfile_os)
                         containerfile: Path = self.path / f"{containerfile_base_name}.{variant.extension}"
                         try:
-                            rendered = tpl.render(**template_values, **render_kwargs)
+                            rendered = tpl.render(**template_values)
                         except (jinja2.TemplateError, BakeryTemplateError) as e:
                             log.error(
                                 f"Failed to render template [bold]{tpl_rel_path}[/] for image '{self.parent.name}' "
@@ -517,7 +513,7 @@ def render_files(
                             continue
                         log.debug(f"[bright_black]Rendering [bold]{containerfile}")
                         copy2(tpl_full_path, containerfile)
-                        containerfile.write_text(rendered)
+                        containerfile.write_text(normalize_rendered_output(rendered))
 
                 # Render other templates once
                 else:
@@ -526,7 +522,7 @@ def render_files(
                     output_file.parent.mkdir(parents=True, exist_ok=True)
                     template_values = self.generate_template_values()
                     try:
-                        rendered = tpl.render(**template_values, **render_kwargs)
+                        rendered = tpl.render(**template_values)
                     except (jinja2.TemplateError, BakeryTemplateError) as e:
                         log.error(
                             f"Failed to render template [bold]{tpl_rel_path}[/] for image '{self.parent.name}' "
@@ -545,7 +541,7 @@ def render_files(
                         continue
                     log.debug(f"[bright_black]Rendering [bold]{output_file}")
                     copy2(tpl_full_path, output_file)
-                    output_file.write_text(rendered)
+                    output_file.write_text(normalize_rendered_output(rendered))
 
         if exceptions:
             if len(exceptions) == 1:

posit-bakery/posit_bakery/config/templating/render.py

@@ -42,3 +42,21 @@ def render_template(template: str, **kwargs) -> str:
     """
     template = jinja2_env().from_string(template)
     return template.render(**kwargs).strip()
+
+
+def normalize_rendered_output(text: str) -> str:
+    """Normalize rendered template output to match common pre-commit hook fixes.
+
+    Strips trailing spaces and tabs from each line and ensures the result
+    ends with exactly one newline (or stays empty if it was empty). This
+    matches the output of the `trailing-whitespace` and `end-of-file-fixer`
+    pre-commit hooks, so files written by bakery's renderer don't fail
+    those hooks in consuming repositories.
+
+    :param text: The rendered template text to normalize.
+    :return: The normalized text.
+    """
+    text = re.sub(r"[ \t]+$", "", text, flags=re.MULTILINE)
+    if text:
+        text = text.rstrip("\n") + "\n"
+    return text

posit-bakery/test/config/templating/test_render.py

@@ -1,7 +1,7 @@
 import jinja2
 import pytest
 
-from posit_bakery.config.templating.render import jinja2_env
+from posit_bakery.config.templating.render import jinja2_env, normalize_rendered_output
 
 
 pytestmark = [
@@ -61,3 +61,35 @@ def test_render_template():
     template = "{{ 'Test String' | condense }} {{ 'foo-bar-baz' | regexReplace('-', '_') }}"
     rendered = jinja2_env().from_string(template).render()
     assert rendered == "TestString foo_bar_baz"
+
+
+class TestNormalizeRenderedOutput:
+    def test_strips_trailing_spaces(self):
+        assert normalize_rendered_output("foo  \nbar\n") == "foo\nbar\n"
+
+    def test_strips_trailing_tabs(self):
+        assert normalize_rendered_output("foo\t\nbar\n") == "foo\nbar\n"
+
+    def test_strips_mixed_trailing_whitespace(self):
+        assert normalize_rendered_output("foo \t \nbar\n") == "foo\nbar\n"
+
+    def test_strips_whitespace_only_lines(self):
+        assert normalize_rendered_output("a\n  \nb\n") == "a\n\nb\n"
+
+    def test_collapses_multiple_trailing_newlines(self):
+        assert normalize_rendered_output("foo\n\n\n") == "foo\n"
+
+    def test_adds_missing_trailing_newline(self):
+        assert normalize_rendered_output("foo\nbar") == "foo\nbar\n"
+
+    def test_preserves_single_trailing_newline(self):
+        assert normalize_rendered_output("foo\nbar\n") == "foo\nbar\n"
+
+    def test_empty_input_stays_empty(self):
+        assert normalize_rendered_output("") == ""
+
+    def test_preserves_interior_blank_lines(self):
+        assert normalize_rendered_output("a\n\nb\n") == "a\n\nb\n"
+
+    def test_does_not_touch_leading_whitespace(self):
+        assert normalize_rendered_output("    indented\n") == "    indented\n"

posit-bakery/test/config/test_e2e.py

@@ -7,6 +7,7 @@
 
 from posit_bakery.config import BakeryConfig
 from posit_bakery.config.templating import TPL_BAKERY_CONFIG_YAML, render_template
+from posit_bakery.config.templating.render import normalize_rendered_output
 from posit_bakery.const import DEFAULT_BASE_IMAGE
 from test.helpers import IMAGE_INDENT, VERSION_INDENT
 
@@ -30,7 +31,7 @@ def test_create_from_scratch(tmpdir, common_image_variants):
 
     # Check that the bakery.yaml file was created as expected from its template.
     assert config_file.is_file()
-    expected_config = render_template(TPL_BAKERY_CONFIG_YAML, repo_url=repo_url)
+    expected_config = normalize_rendered_output(render_template(TPL_BAKERY_CONFIG_YAML, repo_url=repo_url))
     assert config_file.read_text() == expected_config
 
     # Load the new project