Do not always add a trailing newline upon saving

.pre-commit-config.yaml

@@ -28,6 +28,7 @@ repos:
       - id: check-yaml
       - id: detect-private-key
       - id: end-of-file-fixer
+        exclude: tests/data/spec_no_trailing_newline/test.spec
       - id: mixed-line-ending
       - id: trailing-whitespace
   - repo: https://github.com/PyCQA/flake8

specfile/specfile.py

@@ -65,7 +65,7 @@ def __init__(
         """
         self.autosave = autosave
         self._path = Path(path)
-        self._lines = self._read_lines(self._path)
+        self._lines, self._trailing_newline = self._read_lines(self._path)
         self._parser = SpecParser(
             Path(sourcedir or self.path.parent), macros, force_parse
         )
@@ -89,7 +89,7 @@ def __repr__(self) -> str:
         )
 
     def __str__(self) -> str:
-        return "\n".join(self._lines) + "\n"
+        return "\n".join(self._lines) + ("\n" if self._trailing_newline else "")
 
     def __enter__(self) -> "Specfile":
         return self
@@ -103,8 +103,9 @@ def __exit__(
         self.save()
 
     @staticmethod
-    def _read_lines(path: Path) -> List[str]:
-        return path.read_text(encoding="utf8", errors="surrogateescape").splitlines()
+    def _read_lines(path: Path) -> Tuple[List[str], bool]:
+        content = path.read_text(encoding="utf8", errors="surrogateescape")
+        return content.splitlines(), content[-1] == "\n"
 
     @property
     def path(self) -> Path:
@@ -159,7 +160,7 @@ def rpm_spec(self) -> rpm.spec:
 
     def reload(self) -> None:
         """Reloads the spec file content."""
-        self._lines = self._read_lines(self.path)
+        self._lines, self._trailing_newline = self._read_lines(self.path)
 
     def save(self) -> None:
         """Saves the spec file content."""

tests/constants.py

@@ -18,6 +18,7 @@
 SPEC_MULTIPLE_SOURCES = DATA_DIR / "spec_multiple_sources"
 SPEC_COMMENTED_PATCHES = DATA_DIR / "spec_commented_patches"
 SPEC_SHELL_EXPANSIONS = DATA_DIR / "spec_shell_expansions"
+SPEC_NO_TRAILING_NEWLINE = DATA_DIR / "spec_no_trailing_newline"
 SPEC_CONDITIONALIZED_CHANGELOG = DATA_DIR / "spec_conditionalized_changelog"
 SPEC_CONDITIONALIZED_VERSION = DATA_DIR / "spec_conditionalized_version"
 

tests/data/spec_no_trailing_newline/patch0.patch

@@ -0,0 +1,18 @@
+From b7af0b9194585c6d208de3a0e9978d5ad9c5d97b Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Nikola=20Forr=C3=B3?= <[email protected]>
+Date: Wed, 16 Mar 2022 10:29:59 +0100
+Subject: [PATCH 1/3] patch0
+
+---
+ test.txt | 1 +
+ 1 file changed, 1 insertion(+)
+
+diff --git a/test.txt b/test.txt
+index 9daeafb..dec2cbe 100644
+--- a/test.txt
++++ b/test.txt
+@@ -1 +1,2 @@
+ test
++test
+--
+2.35.1

tests/data/spec_no_trailing_newline/patch1.patch

@@ -0,0 +1,19 @@
+From 6d5d1561b3ccf2df9d001a7af011144acc352361 Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Nikola=20Forr=C3=B3?= <[email protected]>
+Date: Wed, 16 Mar 2022 10:30:15 +0100
+Subject: [PATCH 2/3] patch1
+
+---
+ test.txt | 1 +
+ 1 file changed, 1 insertion(+)
+
+diff --git a/test.txt b/test.txt
+index dec2cbe..0867e73 100644
+--- a/test.txt
++++ b/test.txt
+@@ -1,2 +1,3 @@
+ test
+ test
++test
+--
+2.35.1

tests/data/spec_no_trailing_newline/patch2.patch

@@ -0,0 +1,20 @@
+From ae1d3bbca0caf1cce1842ceab4c6d7252c0a7bd8 Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Nikola=20Forr=C3=B3?= <[email protected]>
+Date: Wed, 16 Mar 2022 10:30:29 +0100
+Subject: [PATCH 3/3] patch2
+
+---
+ test.txt | 1 +
+ 1 file changed, 1 insertion(+)
+
+diff --git a/test.txt b/test.txt
+index 0867e73..d0c7fbe 100644
+--- a/test.txt
++++ b/test.txt
+@@ -1,3 +1,4 @@
+ test
+ test
+ test
++test
+--
+2.35.1

tests/data/spec_no_trailing_newline/test.spec

@@ -0,0 +1,24 @@
+Name:           test
+Version:        0.1
+Release:        1%{?dist}
+Summary:        Test package
+
+License:        MIT
+
+Source:         %{name}-%{version}.tar.xz
+Patch0:         patch0.patch
+Patch1:         patch1.patch
+Patch2:         patch2.patch
+
+
+%description
+Test package
+
+
+%prep
+%autosetup -p1
+
+
+%changelog
+* Thu Jun 07 2018 Nikola Forró <[email protected]> - 0.1-1
+- first version

tests/integration/conftest.py

@@ -15,6 +15,7 @@
     SPEC_MACROS,
     SPEC_MINIMAL,
     SPEC_MULTIPLE_SOURCES,
+    SPEC_NO_TRAILING_NEWLINE,
     SPEC_PATCHLIST,
     SPEC_PRERELEASE,
     SPEC_PRERELEASE2,
@@ -116,6 +117,13 @@ def spec_shell_expansions(tmp_path):
     return destination / SPECFILE
 
 
+@pytest.fixture(scope="function")
+def spec_no_trailing_newline(tmp_path):
+    destination = tmp_path / "spec_no_trailing_newline"
+    shutil.copytree(SPEC_NO_TRAILING_NEWLINE, destination)
+    return destination / SPECFILE
+
+
 @pytest.fixture(scope="function")
 def spec_conditionalized_changelog(tmp_path):
     specfile_path = tmp_path / SPECFILE

tests/integration/test_specfile.py

@@ -661,3 +661,10 @@ def test_update_version(
         assert md.upstream_version.body != version
     assert spec.version == version
     assert spec.expanded_version == version
+
+
+def test_trailing_newline(spec_autosetup, spec_no_trailing_newline):
+    spec = Specfile(spec_autosetup)
+    assert str(spec)[-1] == "\n"
+    spec = Specfile(spec_no_trailing_newline)
+    assert str(spec)[-1] != "\n"