Update the Lavalink version parsing and add tests for it (#6093)

redbot/cogs/audio/manager.py

@@ -10,6 +10,7 @@ import shlex
 import shutil
 import tempfile
 from typing import ClassVar, Final, List, Optional, Pattern, Tuple, Union, TYPE_CHECKING
+from typing_extensions import Self
 
 import aiohttp
 import lavalink
@@ -47,9 +48,6 @@ if TYPE_CHECKING:
 
 _ = Translator("Audio", pathlib.Path(__file__))
 log = getLogger("red.Audio.manager")
-LAVALINK_DOWNLOAD_DIR: Final[pathlib.Path] = data_manager.cog_data_path(raw_name="Audio")
-LAVALINK_JAR_FILE: Final[pathlib.Path] = LAVALINK_DOWNLOAD_DIR / "Lavalink.jar"
-LAVALINK_APP_YML: Final[pathlib.Path] = LAVALINK_DOWNLOAD_DIR / "application.yml"
 
 _FAILED_TO_START: Final[Pattern] = re.compile(rb"Web server failed to start\. (.*)")
 
@@ -109,6 +107,9 @@ LAVALINK_VERSION_LINE_PRE35: Final[Pattern] = re.compile(
     rb"^Version:\s+(?P<version>\S+)$", re.MULTILINE | re.VERBOSE
 )
 # used for LL 3.5-rc4 and newer
+# This regex is limited to the realistic usage in the LL version number,
+# not everything that could be a part of it according to the spec.
+# We can easily release an update to this regex in the future if it ever becomes necessary.
 LAVALINK_VERSION_LINE: Final[Pattern] = re.compile(
     rb"""
     ^
@@ -117,9 +118,11 @@ LAVALINK_VERSION_LINE: Final[Pattern] = re.compile(
         (?P<major>0|[1-9]\d*)\.(?P<minor>0|[1-9]\d*)
         # Before LL 3.6, when patch version == 0, it was stripped from the version string
         (?:\.(?P<patch>0|[1-9]\d*))?
-        (?:-rc(?P<rc>0|[1-9]\d*))?
-        # only used by our downstream Lavalink if we need to make a release before upstream
-        (?:_red(?P<red>[1-9]\d*))?
+        # Before LL 3.6, the dot in rc.N was optional
+        (?:-rc\.?(?P<rc>0|[1-9]\d*))?
+        # additional build metadata, can be used by our downstream Lavalink
+        # if we need to alter an upstream release
+        (?:\+red\.(?P<red>[1-9]\d*))?
     )
     $
     """,
@@ -135,6 +138,19 @@ class LavalinkOldVersion:
     def __str__(self) -> None:
         return f"{self.raw_version}_{self.build_number}"
 
+    @classmethod
+    def from_version_output(cls, output: bytes) -> Self:
+        build_match = LAVALINK_BUILD_LINE.search(output)
+        if build_match is None:
+            raise ValueError("Could not find Build line in the given `--version` output.")
+        version_match = LAVALINK_VERSION_LINE_PRE35.search(output)
+        if version_match is None:
+            raise ValueError("Could not find Version line in the given `--version` output.")
+        return cls(
+            raw_version=version_match["version"].decode(),
+            build_number=int(build_match["build"]),
+        )
+
     def __eq__(self, other: object) -> bool:
         if isinstance(other, LavalinkOldVersion):
             return self.build_number == other.build_number
@@ -195,6 +211,19 @@ class LavalinkVersion:
             version += f"_red{self.red}"
         return version
 
+    @classmethod
+    def from_version_output(cls, output: bytes) -> Self:
+        match = LAVALINK_VERSION_LINE.search(output)
+        if match is None:
+            raise ValueError("Could not find Version line in the given `--version` output.")
+        return LavalinkVersion(
+            major=int(match["major"]),
+            minor=int(match["minor"]),
+            patch=int(match["patch"] or 0),
+            rc=int(match["rc"]) if match["rc"] is not None else None,
+            red=int(match["red"] or 0),
+        )
+
     def _get_comparison_tuple(self) -> Tuple[int, int, int, bool, int, int]:
         return self.major, self.minor, self.patch, self.rc is None, self.rc or 0, self.red
 
@@ -265,6 +294,18 @@ class ServerManager:
         self._args = []
         self._pipe_task = None
 
+    @property
+    def lavalink_download_dir(self) -> pathlib.Path:
+        return data_manager.cog_data_path(raw_name="Audio")
+
+    @property
+    def lavalink_jar_file(self) -> pathlib.Path:
+        return self.lavalink_download_dir / "Lavalink.jar"
+
+    @property
+    def lavalink_app_yml(self) -> pathlib.Path:
+        return self.lavalink_download_dir / "application.yml"
+
     @property
     def path(self) -> Optional[str]:
         return self._java_exc
@@ -330,7 +371,7 @@ class ServerManager:
             self._proc = (
                 await asyncio.subprocess.create_subprocess_exec(  # pylint:disable=no-member
                     *args,
-                    cwd=str(LAVALINK_DOWNLOAD_DIR),
+                    cwd=str(self.lavalink_download_dir),
                     stdout=asyncio.subprocess.PIPE,
                     stderr=asyncio.subprocess.STDOUT,
                 )
@@ -351,7 +392,7 @@ class ServerManager:
 
     async def process_settings(self):
         data = change_dict_naming_convention(await self._config.yaml.all())
-        with open(LAVALINK_APP_YML, "w") as f:
+        with open(self.lavalink_app_yml, "w") as f:
             yaml.safe_dump(data, f)
 
     async def _get_jar_args(self) -> Tuple[List[str], Optional[str]]:
@@ -392,7 +433,7 @@ class ServerManager:
                 "please fix this by setting the correct value with '[p]llset heapsize'.",
             )
 
-        command_args.extend(["-jar", str(LAVALINK_JAR_FILE)])
+        command_args.extend(["-jar", str(self.lavalink_jar_file)])
         self._args = command_args
         return command_args, invalid
 
@@ -522,7 +563,7 @@ class ServerManager:
                     finally:
                         file.close()
 
-                shutil.move(path, str(LAVALINK_JAR_FILE), copy_function=shutil.copyfile)
+                shutil.move(path, str(self.lavalink_jar_file), copy_function=shutil.copyfile)
 
         log.info("Successfully downloaded Lavalink.jar (%s bytes written)", format(nbytes, ","))
         await self._is_up_to_date()
@@ -535,7 +576,7 @@ class ServerManager:
         args.append("--version")
         _proc = await asyncio.subprocess.create_subprocess_exec(  # pylint:disable=no-member
             *args,
-            cwd=str(LAVALINK_DOWNLOAD_DIR),
+            cwd=str(self.lavalink_download_dir),
             stdout=asyncio.subprocess.PIPE,
             stderr=asyncio.subprocess.STDOUT,
         )
@@ -554,24 +595,17 @@ class ServerManager:
             return False
 
         if (build := LAVALINK_BUILD_LINE.search(stdout)) is not None:
-            if (version := LAVALINK_VERSION_LINE_PRE35.search(stdout)) is None:
+            try:
+                self._lavalink_version = LavalinkOldVersion.from_version_output(stdout)
+            except ValueError:
                 # Output is unexpected, suspect corrupted jarfile
                 return False
-            self._lavalink_version = LavalinkOldVersion(
-                raw_version=version["version"].decode(),
-                build_number=int(build["build"]),
-            )
-        elif (version := LAVALINK_VERSION_LINE.search(stdout)) is not None:
-            self._lavalink_version = LavalinkVersion(
-                major=int(version["major"]),
-                minor=int(version["minor"]),
-                patch=int(version["patch"] or 0),
-                rc=int(version["rc"]) if version["rc"] is not None else None,
-                red=int(version["red"] or 0),
-            )
         else:
-            # Output is unexpected, suspect corrupted jarfile
-            return False
+            try:
+                self._lavalink_version = LavalinkVersion.from_version_output(stdout)
+            except ValueError:
+                # Output is unexpected, suspect corrupted jarfile
+                return False
         date = buildtime["build_time"].decode()
         date = date.replace(".", "/")
         self._lavalink_branch = branch["branch"].decode()
@@ -582,7 +616,7 @@ class ServerManager:
         return self._up_to_date
 
     async def maybe_download_jar(self):
-        if not (LAVALINK_JAR_FILE.exists() and await self._is_up_to_date()):
+        if not (self.lavalink_jar_file.exists() and await self._is_up_to_date()):
             await self._download_jar()
 
     async def wait_until_ready(self, timeout: Optional[float] = None):