Add support for openSUSE style detached changelogs (#444)

Add support for openSUSE style detached changelogs

This PR adds some hacky support for detached/openSUSE style changes files that are inserted into the %changelog section by the open build service.
The tests are not yet all passing, as there is a discrepancy between str(DetachedChangelog) and respective section in str(spec). I'm not sure if this is caused by my (probably rather odd) approach here or whether this is even required?
TODO:

 Write new tests or update the old ones to cover new functionality.
 Update doc-strings where appropriate.
 Update or write new documentation in packit/packit.dev.



Fixes
Related to packit/packit#2399
Merge before/after

RELEASE NOTES BEGIN
Add support for detached (open)SUSE style changelogs
RELEASE NOTES END

Reviewed-by: Nikola Forró

Author: softwarefactory-project-zuul[bot]

specfile/changelog.py

@@ -9,6 +9,7 @@
 import re
 import shutil
 import subprocess
+from enum import Enum, auto, unique
 from typing import List, Optional, Union, overload
 
 from specfile.exceptions import SpecfileException
@@ -34,6 +35,24 @@
     "Dec",
 )
 
+_OPENSUSE_CHANGELOG_SEPARATOR = 67 * "-"
+
+
+@unique
+class ChangelogStyle(Enum):
+    """Style of changelog entries"""
+
+    #: standard changelog entries parseable by RPM (used in Fedora, RHEL, etc.):
+    #: * $DATE $AUTHOR <$EMAIL> - $EVR
+    #: $ENTRY
+    standard = auto()
+
+    #: openSUSE/SUSE style detached changelog:
+    #: -------------------------------------------------------------------
+    #: $DATE - $AUTHOR <$EMAIL>
+    #: $ENTRY
+    openSUSE = auto()
+
 
 class ChangelogEntry:
     """
@@ -168,6 +187,13 @@ def day_of_month_padding(self) -> str:
             return ""
         return m.group("wsp") + (m.group("zp") or "")
 
+    @property
+    def style(self) -> ChangelogStyle:
+        """Style of this changelog entry (standard vs openSUSE)."""
+        if self.header.startswith(_OPENSUSE_CHANGELOG_SEPARATOR):
+            return ChangelogStyle.openSUSE
+        return ChangelogStyle.standard
+
     @classmethod
     def assemble(
         cls,
@@ -177,37 +203,63 @@ def assemble(
         evr: Optional[str] = None,
         day_of_month_padding: str = "0",
         append_newline: bool = True,
+        style: ChangelogStyle = ChangelogStyle.standard,
     ) -> "ChangelogEntry":
         """
         Assembles a changelog entry.
 
         Args:
             timestamp: Timestamp of the entry.
                 Supply `datetime` rather than `date` for extended format.
+                openSUSE-style changelog entries mandate extended format, so if a `date`
+                is supplied, the timestamp will be set to noon of that day.
             author: Author of the entry.
             content: List of lines forming the content of the entry.
             evr: EVR (epoch, version, release) of the entry.
+                Ignored if `style` is `ChangelogStyle.openSUSE`.
             day_of_month_padding: Padding to apply to day of month in the timestamp.
             append_newline: Whether the entry should be followed by an empty line.
+            style: Which style of changelog should be created.
 
         Returns:
             New instance of `ChangelogEntry` class.
         """
         weekday = WEEKDAYS[timestamp.weekday()]
         month = MONTHS[timestamp.month - 1]
-        header = f"* {weekday} {month}"
+
+        if style == ChangelogStyle.standard:
+            header = "* "
+        else:
+            header = _OPENSUSE_CHANGELOG_SEPARATOR + "\n"
+        header += f"{weekday} {month}"
+
         if day_of_month_padding.endswith("0"):
             header += f" {day_of_month_padding[:-1]}{timestamp.day:02}"
         else:
             header += f" {day_of_month_padding}{timestamp.day}"
+
+        # convert to extended format for openSUSE style changelogs
+        if style == ChangelogStyle.openSUSE and not isinstance(
+            timestamp, datetime.datetime
+        ):
+            timestamp = datetime.datetime(
+                year=timestamp.year, month=timestamp.month, day=timestamp.day, hour=12
+            )
+
         if isinstance(timestamp, datetime.datetime):
             # extended format
             if not timestamp.tzinfo:
                 timestamp = timestamp.replace(tzinfo=datetime.timezone.utc)
             header += f" {timestamp:%H:%M:%S %Z}"
-        header += f" {timestamp:%Y} {author}"
-        if evr is not None:
+        header += f" {timestamp:%Y} "
+
+        if style == ChangelogStyle.openSUSE:
+            header += "- "
+        header += author
+
+        if evr is not None and style == ChangelogStyle.standard:
             header += f" - {evr}"
+
         return cls(header, content, [""] if append_newline else None)
 
 
@@ -350,13 +402,25 @@ def extract_following_lines(content: List[str]) -> List[str]:
         predecessor = []
         header = None
         content: List[str] = []
-        for line in section:
-            if line.startswith("*"):
+
+        for i, line in enumerate(section):
+            if line == _OPENSUSE_CHANGELOG_SEPARATOR:
+                continue
+
+            prev_line_is_opensuse_separator = (
+                i >= 1 and section[i - 1] == _OPENSUSE_CHANGELOG_SEPARATOR
+            )
+            if line.startswith("*") or prev_line_is_opensuse_separator:
                 if header is None or "".join(content).strip():
                     if header:
                         following_lines = extract_following_lines(content)
                         data.insert(0, ChangelogEntry(header, content, following_lines))
-                    header = line
+
+                    if prev_line_is_opensuse_separator:
+                        header = _OPENSUSE_CHANGELOG_SEPARATOR + "\n"
+                    else:
+                        header = ""
+                    header += line
                     content = []
                 else:
                     content.append(line)

tests/unit/test_changelog.py

@@ -3,11 +3,16 @@
 
 import copy
 import datetime
-from typing import Optional
+from typing import List, Optional, Union
 
 import pytest
 
-from specfile.changelog import Changelog, ChangelogEntry
+from specfile.changelog import (
+    _OPENSUSE_CHANGELOG_SEPARATOR,
+    Changelog,
+    ChangelogEntry,
+    ChangelogStyle,
+)
 from specfile.sections import Section
 from specfile.utils import EVR
 
@@ -240,6 +245,140 @@ def test_parse():
     ]
     assert not changelog[6].extended_timestamp
 
+    assert all(
+        changelog_entry.style == ChangelogStyle.standard
+        for changelog_entry in changelog
+    )
+
+
+def test_suse_style_changelog_parse():
+    changelog = Changelog.parse(
+        Section(
+            "changelog",
+            data=[
+                "-------------------------------------------------------------------",
+                (
+                    hdr1 := "Tue Dec 17 14:21:37 UTC 2024 - "
+                    + (dc := "Dan Čermák <[email protected]>")
+                ),
+                "",
+                (content1 := "- First version"),
+                "",
+                "-------------------------------------------------------------------",
+                (hdr2 := f"Mon Nov  4 17:47:23 UTC 2024 - {dc}"),
+                "",
+                (content2 := "- # [0.9.37] - September 4th, 2024"),
+                "",
+                "-------------------------------------------------------------------",
+                (
+                    hdr3 := "Fri May 17 09:14:20 UTC 2024 - "
+                    + "Dominique Leuenberger <[email protected]>"
+                ),
+                "",
+                (content3 := "- Use %patch -P N instead of deprecated %patchN syntax."),
+                "",
+                "-------------------------------------------------------------------",
+                (
+                    hdr4 := "Mon Oct 10 13:27:24 UTC 2022 - Stephan Kulow <[email protected]>"
+                ),
+                "",
+                (content4_1 := "updated to version 0.9.28"),
+                (content4_2 := " see installed CHANGELOG.md"),
+                "",
+                "",
+                "-------------------------------------------------------------------",
+                (
+                    hdr5 := "Fri Jun 25 07:31:34 UTC 2021 - Dan Čermák <[email protected]>"
+                ),
+                "",
+                (content5_1 := "- New upstream release 0.9.26"),
+                "",
+                (content5_2 := "  - Add support for Ruby 3.0 and fix tests"),
+                (
+                    content5_3 := "  - Fix support for `frozen_string_literal: false`"
+                    + " magic comments (#1363)"
+                ),
+                "",
+                "",
+            ],
+        )
+    )
+
+    assert isinstance(changelog, Changelog)
+    assert len(changelog) == 5
+
+    for changelog_entry, hdr, content in zip(
+        changelog,
+        reversed((hdr1, hdr2, hdr3, hdr4, hdr5)),
+        reversed(
+            (
+                [content1],
+                [content2],
+                [content3],
+                [content4_1, content4_2],
+                [content5_1, "", content5_2, content5_3],
+            )
+        ),
+    ):
+
+        assert isinstance(changelog_entry, ChangelogEntry)
+        assert changelog_entry.evr is None
+        assert changelog_entry.header == _OPENSUSE_CHANGELOG_SEPARATOR + "\n" + hdr
+        assert changelog_entry.content == [""] + content
+        assert changelog_entry.extended_timestamp
+        assert changelog_entry.style == ChangelogStyle.openSUSE
+
+
+@pytest.mark.parametrize(
+    "timestamp,author,content,entry",
+    (
+        [
+            (
+                datetime.datetime(2021, 6, 25, 7, 31, 34),
+                "Dan Čermák <[email protected]>",
+                content_1 := ["", "New upstream release 0.9.26"],
+                ChangelogEntry(
+                    header=_OPENSUSE_CHANGELOG_SEPARATOR
+                    + "\n"
+                    + "Fri Jun 25 07:31:34 UTC 2021 - Dan Čermák <[email protected]>",
+                    content=content_1,
+                ),
+            ),
+            (
+                datetime.date(2021, 6, 25),
+                "Dan Čermák <[email protected]>",
+                content_2 := [
+                    "",
+                    "New upstream release 0.26",
+                    "Fixed a major regression in Foo",
+                ],
+                ChangelogEntry(
+                    header=_OPENSUSE_CHANGELOG_SEPARATOR
+                    + "\n"
+                    + "Fri Jun 25 12:00:00 UTC 2021 - Dan Čermák <[email protected]>",
+                    content=content_2,
+                ),
+            ),
+        ]
+    ),
+)
+def test_create_opensuse_changelog_assemble(
+    timestamp: Union[datetime.datetime, datetime.date],
+    author: str,
+    content: List[str],
+    entry: ChangelogEntry,
+) -> None:
+    assert (
+        ChangelogEntry.assemble(
+            timestamp,
+            author,
+            content,
+            style=ChangelogStyle.openSUSE,
+            append_newline=False,
+        )
+        == entry
+    )
+
 
 def test_get_raw_section_data():
     tzinfo = datetime.timezone(datetime.timedelta(hours=2), name="CEST")