docs and recipes updatte

.github/workflows/setup.sh

@@ -15,8 +15,6 @@ pacman -Sy --noconfirm devtools git pyalpm python-inflection python-passlib pyth
 pacman -Sy --noconfirm --asdeps base-devel python-build python-flit python-installer python-tox python-wheel
 # optional dependencies
 if [[ -z $MINIMAL_INSTALL ]]; then
-    # VCS support
-    pacman -Sy --noconfirm breezy darcs mercurial subversion
     # web server
     pacman -Sy --noconfirm python-aioauth-client python-aiohttp python-aiohttp-apispec-git python-aiohttp-cors python-aiohttp-jinja2 python-aiohttp-security python-aiohttp-session python-cryptography python-jinja
     # additional features

Dockerfile

@@ -31,7 +31,6 @@ RUN useradd -m -d "/home/build" -s "/usr/bin/nologin" build && \
     echo "build ALL=(ALL) NOPASSWD: ALL" > "/etc/sudoers.d/build"
 COPY "docker/install-aur-package.sh" "/usr/local/bin/install-aur-package"
 ## install package dependencies
-## darcs is not installed by reasons, because it requires a lot haskell packages which dramatically increase image size
 RUN pacman -Sy --noconfirm --asdeps \
         devtools \
         git \
@@ -50,9 +49,7 @@ RUN pacman -Sy --noconfirm --asdeps \
         python-wheel \
         && \
     pacman -Sy --noconfirm --asdeps \
-        breezy \
         git \
-        mercurial \
         python-aiohttp \
         python-boto3 \
         python-cerberus \
@@ -61,7 +58,6 @@ RUN pacman -Sy --noconfirm --asdeps \
         python-matplotlib \
         python-systemd \
         rsync \
-        subversion \
         && \
     runuser -u build -- install-aur-package \
         python-aioauth-client \

docs/faq/general.rst

@@ -265,11 +265,7 @@ TL;DR
 How to update VCS packages
 ^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-Normally the service handles VCS packages correctly, however it requires additional dependencies:
+Normally the service handles VCS packages correctly. The version is updated in clean chroot, no additional actions are required.
-
-.. code-block:: shell
-
-   pacman -S breezy darcs mercurial subversion
 
 How to review changes before build
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

package/archlinux/PKGBUILD

@@ -9,10 +9,7 @@ url="https://github.com/arcan1s/ahriman"
 license=('GPL3')
 depends=('devtools>=1:1.0.0' 'git' 'pyalpm' 'python-inflection' 'python-passlib' 'python-pyelftools' 'python-requests' 'python-srcinfo')
 makedepends=('python-build' 'python-flit' 'python-installer' 'python-wheel')
-optdepends=('breezy: -bzr packages support'
+optdepends=('python-aioauth-client: web server with OAuth2 authorization'
-            'darcs: -darcs packages support'
-            'mercurial: -hg packages support'
-            'python-aioauth-client: web server with OAuth2 authorization'
             'python-aiohttp: web server'
             'python-aiohttp-apispec>=3.0.0: web server'
             'python-aiohttp-cors: web server'
@@ -26,8 +23,7 @@ optdepends=('breezy: -bzr packages support'
             'python-requests-unixsocket2: client report to web server by unix socket'
             'python-jinja: html report generation'
             'python-systemd: journal support'
-            'rsync: sync by using rsync'
+            'rsync: sync by using rsync')
-            'subversion: -svn packages support')
 source=("https://github.com/arcan1s/ahriman/releases/download/$pkgver/$pkgname-$pkgver.tar.gz"
         'ahriman.sysusers'
         'ahriman.tmpfiles')

src/ahriman/core/build_tools/task.py

@@ -17,13 +17,14 @@
 # You should have received a copy of the GNU General Public License
 # along with this program. If not, see <http://www.gnu.org/licenses/>.
 #
+from collections.abc import Generator
 from pathlib import Path
 
 from ahriman.core.build_tools.sources import Sources
 from ahriman.core.configuration import Configuration
 from ahriman.core.exceptions import BuildError
 from ahriman.core.log import LazyLogging
-from ahriman.core.utils import check_output
+from ahriman.core.utils import check_output, package_like
 from ahriman.models.package import Package
 from ahriman.models.pkgbuild_patch import PkgbuildPatch
 from ahriman.models.repository_paths import RepositoryPaths
@@ -67,12 +68,43 @@ class Task(LazyLogging):
         self.makepkg_flags = configuration.getlist("build", "makepkg_flags", fallback=[])
         self.makechrootpkg_flags = configuration.getlist("build", "makechrootpkg_flags", fallback=[])
 
-    def build(self, sources_dir: Path, **kwargs: str | None) -> list[Path]:
+    def _package_archives(self, sources_dir: Path, source_files: list[Path]) -> list[Path]:
+        """
+        extract package archives from the directory
+
+        Args:
+            sources_dir(Path): path to where sources are
+            source_files(list[Path]): list of files which were initially in the directory
+
+        Returns:
+            list[Path]: list of file paths which looks like freshly generated archives
+        """
+        def files() -> Generator[Path, None, None]:
+            for filepath in sources_dir.iterdir():
+                if filepath in source_files:
+                    continue  # skip files which were already there
+                if filepath.suffix == ".log":
+                    continue  # skip log files
+                if not package_like(filepath):
+                    continue  # path doesn't look like a package
+                yield filepath
+
+        # debug packages are always formed as package.base-debug
+        # see /usr/share/makepkg/util/pkgbuild.sh for more details
+        debug_package_prefix = f"{self.package.base}-debug-"
+        return [
+            package
+            for package in files()
+            if self.include_debug_packages or not package.name.startswith(debug_package_prefix)
+        ]
+
+    def build(self, sources_dir: Path, *, dry_run: bool = False, **kwargs: str | None) -> list[Path]:
         """
         run package build
 
         Args:
             sources_dir(Path): path to where sources are
+            dry_run(bool, optional): do not perform build itself (Default value = False)
             **kwargs(str | None): environment variables to be passed to build processes
 
         Returns:
@@ -82,6 +114,8 @@ class Task(LazyLogging):
         command.extend(self.archbuild_flags)
         command.extend(["--"] + self.makechrootpkg_flags)
         command.extend(["--"] + self.makepkg_flags)
+        if dry_run:
+            command.extend(["--nobuild"])
         self.logger.info("using %s for %s", command, self.package.base)
 
         environment: dict[str, str] = {
@@ -91,6 +125,7 @@ class Task(LazyLogging):
         }
         self.logger.info("using environment variables %s", environment)
 
+        source_files = list(sources_dir.iterdir())
         check_output(
             *command,
             exception=BuildError.from_process(self.package.base),
@@ -100,20 +135,7 @@ class Task(LazyLogging):
             environment=environment,
         )
 
-        package_list_command = ["makepkg", "--packagelist"]
+        return self._package_archives(sources_dir, source_files)
-        if not self.include_debug_packages:
-            package_list_command.append("OPTIONS=(!debug)")  # disable debug flag manually
-        packages = check_output(
-            *package_list_command,
-            exception=BuildError.from_process(self.package.base),
-            cwd=sources_dir,
-            logger=self.logger,
-            environment=environment,
-        ).splitlines()
-        # some dirty magic here
-        # the filter is applied in order to make sure that result will only contain packages which were actually built
-        # e.g. in some cases packagelist command produces debug packages which were not actually built
-        return list(filter(lambda path: path.is_file(), map(Path, packages)))
 
     def init(self, sources_dir: Path, patches: list[PkgbuildPatch], local_version: str | None) -> str | None:
         """

src/ahriman/core/repository/package_info.py

@@ -58,7 +58,7 @@ class PackageInfo(RepositoryProperties):
                     # force version to max of them
                     self.logger.warning("version of %s differs, found %s and %s",
                                         current.base, current.version, local.version)
-                    if current.is_outdated(local, self.paths, calculate_version=False):
+                    if current.is_outdated(local, self.configuration, calculate_version=False):
                         current.version = local.version
                 current.packages.update(local.packages)
             except Exception:

src/ahriman/core/repository/repository_properties.py

@@ -51,7 +51,6 @@ class RepositoryProperties(EventLogger, LazyLogging):
         scan_paths(ScanPaths): scan paths for the implicit dependencies
         sign(GPG): GPG wrapper instance
         triggers(TriggerLoader): triggers holder
-        vcs_allowed_age(int): maximal age of the VCS packages before they will be checked
     """
 
     def __init__(self, repository_id: RepositoryId, configuration: Configuration, database: SQLite, *, report: bool,
@@ -70,8 +69,6 @@ class RepositoryProperties(EventLogger, LazyLogging):
         self.configuration = configuration
         self.database = database
 
-        self.vcs_allowed_age = configuration.getint("build", "vcs_allowed_age", fallback=0)
-
         self.paths: RepositoryPaths = configuration.repository_paths  # additional workaround for pycharm typing
 
         self.ignore_list = configuration.getlist("build", "ignore_packages", fallback=[])

src/ahriman/core/repository/update_handler.py

@@ -67,10 +67,7 @@ class UpdateHandler(PackageInfo, Cleaner):
                 try:
                     remote = load_remote(local)
 
-                    if local.is_outdated(
+                    if local.is_outdated(remote, self.configuration, calculate_version=vcs):
-                            remote, self.paths,
-                            vcs_allowed_age=self.vcs_allowed_age,
-                            calculate_version=vcs):
                         self.reporter.set_pending(local.base)
                         self.event(local.base, EventType.PackageOutdated, "Remote version is newer than local")
                         result.append(remote)
@@ -154,9 +151,7 @@ class UpdateHandler(PackageInfo, Cleaner):
                     if local is None:
                         continue  # we don't add packages automatically
 
-                    if local.is_outdated(remote, self.paths,
+                    if local.is_outdated(remote, self.configuration, calculate_version=vcs):
-                                         vcs_allowed_age=self.vcs_allowed_age,
-                                         calculate_version=vcs):
                         self.reporter.set_pending(local.base)
                         self.event(local.base, EventType.PackageOutdated, "Locally pulled sources are outdated")
                         result.append(remote)

src/ahriman/core/utils.py

@@ -27,7 +27,7 @@ import re
 import selectors
 import subprocess
 
-from collections.abc import Callable, Generator, Iterable
+from collections.abc import Callable, Generator, Iterable, Mapping
 from dataclasses import asdict
 from enum import Enum
 from pathlib import Path
@@ -407,7 +407,7 @@ def safe_filename(source: str) -> str:
     return re.sub(r"[^A-Za-z\d\-._~:\[\]@]", "-", source)
 
 
-def srcinfo_property(key: str, srcinfo: dict[str, Any], package_srcinfo: dict[str, Any], *,
+def srcinfo_property(key: str, srcinfo: Mapping[str, Any], package_srcinfo: Mapping[str, Any], *,
                      default: Any = None) -> Any:
     """
     extract property from SRCINFO. This method extracts property from package if this property is presented in
@@ -416,8 +416,8 @@ def srcinfo_property(key: str, srcinfo: dict[str, Any], package_srcinfo: dict[st
 
     Args:
         key(str): key to extract
-        srcinfo(dict[str, Any]): root structure of SRCINFO
+        srcinfo(Mapping[str, Any]): root structure of SRCINFO
-        package_srcinfo(dict[str, Any]): package specific SRCINFO
+        package_srcinfo(Mapping[str, Any]): package specific SRCINFO
         default(Any, optional): the default value for the specified key (Default value = None)
 
     Returns:
@@ -426,7 +426,7 @@ def srcinfo_property(key: str, srcinfo: dict[str, Any], package_srcinfo: dict[st
     return package_srcinfo.get(key) or srcinfo.get(key) or default
 
 
-def srcinfo_property_list(key: str, srcinfo: dict[str, Any], package_srcinfo: dict[str, Any], *,
+def srcinfo_property_list(key: str, srcinfo: Mapping[str, Any], package_srcinfo: Mapping[str, Any], *,
                           architecture: str | None = None) -> list[Any]:
     """
     extract list property from SRCINFO. Unlike :func:`srcinfo_property()` it supposes that default return value is
@@ -435,8 +435,8 @@ def srcinfo_property_list(key: str, srcinfo: dict[str, Any], package_srcinfo: di
 
     Args:
         key(str): key to extract
-        srcinfo(dict[str, Any]): root structure of SRCINFO
+        srcinfo(Mapping[str, Any]): root structure of SRCINFO
-        package_srcinfo(dict[str, Any]): package specific SRCINFO
+        package_srcinfo(Mapping[str, Any]): package specific SRCINFO
         architecture(str | None, optional): package architecture if set (Default value = None)
 
     Returns:

src/ahriman/models/package.py

@@ -26,19 +26,18 @@ from collections.abc import Callable, Generator, Iterable
 from dataclasses import dataclass
 from pathlib import Path
 from pyalpm import vercmp  # type: ignore[import-not-found]
-from srcinfo.parse import parse_srcinfo  # type: ignore[import-untyped]
 from typing import Any, Self
 from urllib.parse import urlparse
 
 from ahriman.core.alpm.pacman import Pacman
 from ahriman.core.alpm.remote import AUR, Official, OfficialSyncdb
-from ahriman.core.exceptions import PackageInfoError
+from ahriman.core.configuration import Configuration
 from ahriman.core.log import LazyLogging
-from ahriman.core.utils import check_output, dataclass_view, full_version, parse_version, srcinfo_property_list, utcnow
+from ahriman.core.utils import dataclass_view, full_version, parse_version, srcinfo_property_list, utcnow
 from ahriman.models.package_description import PackageDescription
 from ahriman.models.package_source import PackageSource
+from ahriman.models.pkgbuild import Pkgbuild
 from ahriman.models.remote_source import RemoteSource
-from ahriman.models.repository_paths import RepositoryPaths
 
 
 @dataclass(kw_only=True)
@@ -255,25 +254,23 @@ class Package(LazyLogging):
 
         Returns:
             Self: package properties
-
-        Raises:
-            PackageInfoError: if there are parsing errors
         """
-        srcinfo_source = check_output("makepkg", "--printsrcinfo", cwd=path)
+        pkgbuild = Pkgbuild.from_file(path / "PKGBUILD")
-        srcinfo, errors = parse_srcinfo(srcinfo_source)
-        if errors:
-            raise PackageInfoError(errors)
 
         packages = {
             package: PackageDescription(
-                depends=srcinfo_property_list("depends", srcinfo, properties, architecture=architecture),
+                depends=srcinfo_property_list("depends", pkgbuild, properties, architecture=architecture),
-                make_depends=srcinfo_property_list("makedepends", srcinfo, properties, architecture=architecture),
+                make_depends=srcinfo_property_list("makedepends", pkgbuild, properties, architecture=architecture),
-                opt_depends=srcinfo_property_list("optdepends", srcinfo, properties, architecture=architecture),
+                opt_depends=srcinfo_property_list("optdepends", pkgbuild, properties, architecture=architecture),
-                check_depends=srcinfo_property_list("checkdepends", srcinfo, properties, architecture=architecture),
+                check_depends=srcinfo_property_list("checkdepends", pkgbuild, properties, architecture=architecture),
             )
-            for package, properties in srcinfo["packages"].items()
+            for package, properties in pkgbuild.packages().items()
         }
-        version = full_version(srcinfo.get("epoch"), srcinfo["pkgver"], srcinfo["pkgrel"])
+        version = full_version(
+            pkgbuild.get_as("epoch", default=None),
+            pkgbuild.get_as("pkgver"),
+            pkgbuild.get_as("pkgrel"),
+        )
 
         remote = RemoteSource(
             source=PackageSource.Local,
@@ -284,7 +281,7 @@ class Package(LazyLogging):
         )
 
         return cls(
-            base=srcinfo["pkgbase"],
+            base=pkgbuild.get_as("pkgbase"),
             version=version,
             remote=remote,
             packages=packages,
@@ -363,16 +360,12 @@ class Package(LazyLogging):
         Raises:
             PackageInfoError: if there are parsing errors
         """
-        srcinfo_source = check_output("makepkg", "--printsrcinfo", cwd=path)
+        pkgbuild = Pkgbuild.from_file(path / "PKGBUILD")
-        srcinfo, errors = parse_srcinfo(srcinfo_source)
-        if errors:
-            raise PackageInfoError(errors)
-
         # we could use arch property, but for consistency it is better to call special method
         architectures = Package.supported_architectures(path)
 
         for architecture in architectures:
-            for source in srcinfo_property_list("source", srcinfo, {}, architecture=architecture):
+            for source in srcinfo_property_list("source", pkgbuild, {}, architecture=architecture):
                 if "::" in source:
                     _, source = source.split("::", 1)  # in case if filename is specified, remove it
 
@@ -383,7 +376,7 @@ class Package(LazyLogging):
 
                 yield Path(source)
 
-        if (install := srcinfo.get("install", None)) is not None:
+        if isinstance(install := pkgbuild.get("install"), str):  # well, in reality it is either None or str
             yield Path(install)
 
     @staticmethod
@@ -396,15 +389,9 @@ class Package(LazyLogging):
 
         Returns:
             set[str]: list of package supported architectures
-
-        Raises:
-            PackageInfoError: if there are parsing errors
         """
-        srcinfo_source = check_output("makepkg", "--printsrcinfo", cwd=path)
+        pkgbuild = Pkgbuild.from_file(path / "PKGBUILD")
-        srcinfo, errors = parse_srcinfo(srcinfo_source)
+        return set(pkgbuild.get("arch", []))
-        if errors:
-            raise PackageInfoError(errors)
-        return set(srcinfo.get("arch", []))
 
     def _package_list_property(self, extractor: Callable[[PackageDescription], list[str]]) -> list[str]:
         """
@@ -426,39 +413,43 @@ class Package(LazyLogging):
 
         return sorted(set(generator()))
 
-    def actual_version(self, paths: RepositoryPaths) -> str:
+    def actual_version(self, configuration: Configuration) -> str:
         """
         additional method to handle VCS package versions
 
         Args:
-            paths(RepositoryPaths): repository paths instance
+            configuration(Configuration): configuration instance
 
         Returns:
             str: package version if package is not VCS and current version according to VCS otherwise
-
-        Raises:
-            PackageInfoError: if there are parsing errors
         """
         if not self.is_vcs:
             return self.version
 
-        from ahriman.core.build_tools.sources import Sources
+        from ahriman.core.build_tools.task import Task
 
-        Sources.load(paths.cache_for(self.base), self, [], paths)
+        _, repository_id = configuration.check_loaded()
+        paths = configuration.repository_paths
+        task = Task(self, configuration, repository_id.architecture, paths)
 
         try:
-            # update pkgver first
+            # create fresh chroot environment, fetch sources and - automagically - update PKGBUILD
-            check_output("makepkg", "--nodeps", "--nobuild", cwd=paths.cache_for(self.base), logger=self.logger)
+            task.init(paths.cache_for(self.base), [], None)
-            # generate new .SRCINFO and put it to parser
+            task.build(paths.cache_for(self.base), dry_run=False)
-            srcinfo_source = check_output("makepkg", "--printsrcinfo",
-                                          cwd=paths.cache_for(self.base), logger=self.logger)
-            srcinfo, errors = parse_srcinfo(srcinfo_source)
-            if errors:
-                raise PackageInfoError(errors)
 
-            return full_version(srcinfo.get("epoch"), srcinfo["pkgver"], srcinfo["pkgrel"])
+            pkgbuild = Pkgbuild.from_file(paths.cache_for(self.base) / "PKGBUILD")
+
+            return full_version(
+                pkgbuild.get_as("epoch", default=None),
+                pkgbuild.get_as("pkgver"),
+                pkgbuild.get_as("pkgrel"),
+            )
         except Exception:
-            self.logger.exception("cannot determine version of VCS package, make sure that VCS tools are installed")
+            self.logger.exception("cannot determine version of VCS package")
+        finally:
+            # clear log files generated by devtools
+            for log_file in paths.cache_for(self.base).glob("*.log"):
+                log_file.unlink()
 
         return self.version
 
@@ -513,26 +504,25 @@ class Package(LazyLogging):
             if package.build_date is not None
         )
 
-    def is_outdated(self, remote: Package, paths: RepositoryPaths, *,
+    def is_outdated(self, remote: Package, configuration: Configuration, *,
-                    vcs_allowed_age: float | int = 0,
                     calculate_version: bool = True) -> bool:
         """
         check if package is out-of-dated
 
         Args:
             remote(Package): package properties from remote source
-            paths(RepositoryPaths): repository paths instance. Required for VCS packages cache
+            configuration(Configuration): configuration instance
-            vcs_allowed_age(float | int, optional): max age of the built packages before they will be
-                forced to calculate actual version (Default value = 0)
             calculate_version(bool, optional): expand version to actual value (by calculating git versions)
                 (Default value = True)
 
         Returns:
             bool: ``True`` if the package is out-of-dated and ``False`` otherwise
         """
+        vcs_allowed_age = configuration.getint("build", "vcs_allowed_age", fallback=0)
         min_vcs_build_date = utcnow().timestamp() - vcs_allowed_age
+
         if calculate_version and not self.is_newer_than(min_vcs_build_date):
-            remote_version = remote.actual_version(paths)
+            remote_version = remote.actual_version(configuration)
         else:
             remote_version = remote.version
 

src/ahriman/models/pkgbuild.py

@@ -0,0 +1,307 @@
+#
+# Copyright (c) 2021-2024 ahriman team.
+#
+# This file is part of ahriman
+# (see https://github.com/arcan1s/ahriman).
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+#
+import re
+import shlex
+
+from collections.abc import Generator, Iterator, Mapping
+from dataclasses import dataclass
+from enum import StrEnum
+from io import StringIO
+from pathlib import Path
+from typing import IO, Self, TypeVar, cast
+
+from ahriman.models.pkgbuild_patch import PkgbuildPatch
+
+
+T = TypeVar("T", str, list[str])
+U = TypeVar("U", str, list[str], None)
+
+
+class PkgbuildToken(StrEnum):
+    """
+    well-known tokens dictionary
+
+    Attributes:
+        ArrayEnds(PkgbuildToken): (class attribute) array ends token
+        ArrayStarts(PkgbuildToken): (class attribute) array starts token
+        FunctionDeclaration(PkgbuildToken): (class attribute) function declaration token
+        FunctionEnds(PkgbuildToken): (class attribute) function ends token
+        FunctionStarts(PkgbuildToken): (class attribute) function starts token
+    """
+
+    ArrayStarts = "("
+    ArrayEnds = ")"
+
+    FunctionDeclaration = "()"
+    FunctionStarts = "{"
+    FunctionEnds = "}"
+
+
+@dataclass(frozen=True)
+class Pkgbuild(Mapping[str, str | list[str]]):
+    """
+    simple pkgbuild reader implementation in pure python, because others sucks
+
+    Attributes:
+        fields(dict[str, PkgbuildPatch]): PKGBUILD fields
+    """
+
+    fields: dict[str, PkgbuildPatch]
+
+    _ARRAY_ASSIGNMENT = re.compile(r"^(?P<key>\w+)=$")
+    _STRING_ASSIGNMENT = re.compile(r"^(?P<key>\w+)=(?P<value>.+)$")
+    # in addition, functions can have dash to usual assignment
+    _FUNCTION_DECLARATION = re.compile(r"^(?P<key>[\w-]+)$")
+
+    @property
+    def variables(self) -> dict[str, str]:
+        """
+        list of variables defined and (maybe) used in this PKGBUILD
+
+        Returns:
+            dict[str, str]: map of variable name to its value. The value will be included here in case if it presented
+            in the internal dictionary, it is not a function and the value has string type
+        """
+        return {
+            key: value.value
+            for key, value in self.fields.items()
+            if not value.is_function and isinstance(value.value, str)
+        }
+
+    @classmethod
+    def from_file(cls, path: Path) -> Self:
+        """
+        parse PKGBUILD from the file
+
+        Args:
+            path(Path): path to the PKGBUILD file
+
+        Returns:
+            Self: constructed instance of self
+        """
+        with path.open() as input_file:
+            return cls.from_io(input_file)
+
+    @classmethod
+    def from_io(cls, stream: IO[str]) -> Self:
+        """
+        parse PKGBUILD from input stream
+
+        Args:
+            stream: IO[str]: input stream containing PKGBUILD content
+
+        Returns:
+            Self: constructed instance of self
+        """
+        fields = {}
+
+        parser = shlex.shlex(stream, posix=True, punctuation_chars=True)
+        # ignore substitution and extend bash symbols
+        parser.wordchars += "${}#:+"
+        # in case of default behaviour, it will ignore, for example, segment part of url outside of quotes
+        parser.commenters = ""
+        while token := parser.get_token():
+            try:
+                key, value = cls._parse_token(token, parser)
+                fields[key] = value
+            except StopIteration:
+                break
+
+        return cls(fields)
+
+    @staticmethod
+    def _parse_array(parser: shlex.shlex) -> list[str]:
+        """
+        parse array from the PKGBUILD. This method will extract tokens from parser until it matches closing array,
+        modifying source parser state
+
+        Args:
+            parser(shlex.shlex): shell parser instance
+
+        Returns:
+            list[str]: extracted arrays elements
+
+        Raises:
+            ValueError: if array is not closed
+        """
+        def extract() -> Generator[str, None, None]:
+            while token := parser.get_token():
+                if token == PkgbuildToken.ArrayEnds:
+                    break
+                yield token
+
+            if token != PkgbuildToken.ArrayEnds:
+                raise ValueError("No closing array bracket found")
+
+        return list(extract())
+
+    @staticmethod
+    def _parse_function(parser: shlex.shlex) -> str:
+        """
+        parse function from the PKGBUILD. This method will extract tokens from parser until it matches closing function,
+        modifying source parser state. Instead of trying to combine tokens together, it uses positions of the file
+        and read content again in this range
+
+        Args:
+            parser(shlex.shlex): shell parser instance
+
+        Returns:
+            str: function body
+
+        Raises:
+            ValueError: if function body wasn't found or parser input stream doesn't support position reading
+        """
+        io: IO[str] = parser.instream  # type: ignore[assignment]
+
+        # find start and end positions
+        start_position, end_position = -1, -1
+        while token := parser.get_token():
+            match token:
+                case PkgbuildToken.FunctionStarts:
+                    start_position = io.tell()
+                case PkgbuildToken.FunctionEnds:
+                    end_position = io.tell()
+                    break
+
+        if not 0 < start_position < end_position:
+            raise ValueError("Function body wasn't found")
+
+        # read the specified interval from source stream
+        io.seek(start_position - 1)  # start from the previous symbol ("{")
+        content = io.read(end_position - start_position + 1)
+
+        return content
+
+    @staticmethod
+    def _parse_token(token: str, parser: shlex.shlex) -> tuple[str, PkgbuildPatch]:
+        """
+        parse single token to the PKGBUILD field
+
+        Args:
+            token(str): current token
+            parser(shlex.shlex): shell parser instance
+
+        Returns:
+            tuple[str, PkgbuildPatch]: extracted a pair of key and its value
+
+        Raises:
+            StopIteration: if iteration reaches the end of the file
+        """
+        # simple assignment rule
+        if (match := Pkgbuild._STRING_ASSIGNMENT.match(token)) is not None:
+            key = match.group("key")
+            value = match.group("value")
+            return key, PkgbuildPatch(key, value)
+
+        match parser.get_token():
+            # array processing. Arrays will be sent as "key=", "(", values, ")"
+            case PkgbuildToken.ArrayStarts if (match := Pkgbuild._ARRAY_ASSIGNMENT.match(token)) is not None:
+                key = match.group("key")
+                value = Pkgbuild._parse_array(parser)
+                return key, PkgbuildPatch(key, value)
+
+            # functions processing. Function will be sent as "name", "()", "{", body, "}"
+            case PkgbuildToken.FunctionDeclaration if Pkgbuild._FUNCTION_DECLARATION.match(token):
+                key = f"{token}{PkgbuildToken.FunctionDeclaration}"
+                value = Pkgbuild._parse_function(parser)
+                return token, PkgbuildPatch(key, value)  # this is not mistake, assign to token without ()
+
+            # special function case, where "(" and ")" are separated tokens, e.g. "pkgver ( )"
+            case PkgbuildToken.ArrayStarts if Pkgbuild._FUNCTION_DECLARATION.match(token):
+                next_token = parser.get_token()
+                if next_token == PkgbuildToken.ArrayEnds:  # replace closing bracket with "()"
+                    next_token = PkgbuildToken.FunctionDeclaration
+                parser.push_token(next_token)  # type: ignore[arg-type]
+                return Pkgbuild._parse_token(token, parser)
+
+            # some random token received without continuation, lets guess it is empty assignment (i.e. key=)
+            case other if other is not None:
+                return Pkgbuild._parse_token(other, parser)
+
+            # reached the end of the parser
+            case None:
+                raise StopIteration
+
+    def get_as(self, key: str, **kwargs: T | U) -> T | U:
+        """
+        type guard for getting value by key
+
+        Args:
+            key(str): key name
+            default(U, optional): default value to return if no key found
+
+        Returns:
+            T | U: value associated with key or default value if no value found and fallback is provided
+
+        Raises:
+            KeyError: if no key found and no default has been provided
+        """
+        if key not in self:
+            if "default" in kwargs:
+                return kwargs["default"]
+            raise KeyError(key)
+
+        return cast(T, self[key])
+
+    def packages(self) -> dict[str, Self]:
+        """
+        extract properties from internal package functions
+
+        Returns:
+            dict[str, Self]: map of package name to its inner properties if defined
+        """
+        packages = [self["pkgname"]] if isinstance(self["pkgname"], str) else self["pkgname"]
+
+        def io(package_name: str) -> IO[str]:
+            # try to read package specific function and fallback to default otherwise
+            content = self.get_as(f"package_{package_name}", default=None) or self.get_as("package")
+            return StringIO(content)
+
+        return {package: self.from_io(io(package)) for package in packages}
+
+    def __getitem__(self, key: str) -> str | list[str]:
+        """
+        get the field of the PKGBUILD
+
+        Args:
+            key(str): key name
+
+        Returns:
+            str | list[str]: value by the key
+        """
+        return self.fields[key].substitute(self.variables)
+
+    def __iter__(self) -> Iterator[str]:
+        """
+        iterate over the fields
+
+        Returns:
+            Iterator[str]: keys iterator
+        """
+        return iter(self.fields)
+
+    def __len__(self) -> int:
+        """
+        get length of the mapping
+
+        Returns:
+            int: amount of the fields in this PKGBUILD
+        """
+        return len(self.fields)

src/ahriman/models/pkgbuild_patch.py

@@ -21,6 +21,7 @@ import shlex
 
 from dataclasses import dataclass, fields
 from pathlib import Path
+from string import Template
 from typing import Any, Generator, Self
 
 from ahriman.core.utils import dataclass_view, filter_json
@@ -167,6 +168,21 @@ class PkgbuildPatch:
             return f"{self.key} {self.value}"  # no quoting enabled here
         return f"""{self.key}={PkgbuildPatch.quote(self.value)}"""
 
+    def substitute(self, variables: dict[str, str]) -> str | list[str]:
+        """
+        substitute variables into the value
+
+        Args:
+            variables(dict[str, str]): map of variables available for usage
+
+        Returns:
+            str | list[str]: substituted value. All unknown variables will remain as links to their values.
+            This function doesn't support recursive substitution
+        """
+        if isinstance(self.value, str):
+            return Template(self.value).safe_substitute(variables)
+        return [Template(value).safe_substitute(variables) for value in self.value]
+
     def view(self) -> dict[str, Any]:
         """
         generate json patch view