Provide context for macro expansions

When using multiple instances of Specfile, macros have to be expanded
in the right context (because RPM uses a single global macro context,
so this global context has to be emptied and repopulated on every
context switch).

Signed-off-by: Nikola Forró <[email protected]>

Author: nforro

specfile/sourcelist.py

@@ -2,12 +2,15 @@
 # SPDX-License-Identifier: MIT
 
 import collections
-from typing import List, Optional, SupportsIndex, overload
+from typing import TYPE_CHECKING, List, Optional, SupportsIndex, overload
 
 from specfile.rpm import Macros
 from specfile.sections import Section
 from specfile.tags import Comments
 
+if TYPE_CHECKING:
+    from specfile.specfile import Specfile
+
 
 class SourcelistEntry:
     """
@@ -18,9 +21,23 @@ class SourcelistEntry:
         comments: List of comments associated with the source/patch.
     """
 
-    def __init__(self, location: str, comments: Comments) -> None:
+    def __init__(
+        self, location: str, comments: Comments, context: Optional["Specfile"] = None
+    ) -> None:
+        """
+        Constructs a `SourceListEntry` object.
+
+        Args:
+            location: Literal location of the source/patch as stored in the spec file.
+            comments: List of comments associated with the source/patch.
+            context: `Specfile` instance that defines the context for macro expansions.
+
+        Returns:
+            Constructed instance of `SourceListEntry` class.
+        """
         self.location = location
         self.comments = comments.copy()
+        self._context = context
 
     def __eq__(self, other: object) -> bool:
         if not isinstance(other, SourcelistEntry):
@@ -34,6 +51,8 @@ def __repr__(self) -> str:
     @property
     def expanded_location(self) -> str:
         """URL of the source/patch after expanding macros."""
+        if self._context:
+            return self._context.expand(self.location)
         return Macros.expand(self.location)
 
 
@@ -88,12 +107,15 @@ def copy(self) -> "Sourcelist":
         return Sourcelist(self.data, self._remainder)
 
     @classmethod
-    def parse(cls, section: Section) -> "Sourcelist":
+    def parse(
+        cls, section: Section, context: Optional["Specfile"] = None
+    ) -> "Sourcelist":
         """
         Parses a section into sources/patches.
 
         Args:
             section: %sourcelist/%patchlist section.
+            context: `Specfile` instance that defines the context for macro expansions.
 
         Returns:
             Constructed instance of `Sourcelist` class.
@@ -102,7 +124,7 @@ def parse(cls, section: Section) -> "Sourcelist":
         buffer: List[str] = []
         for line in section:
             if line and not line.lstrip().startswith("#"):
-                data.append(SourcelistEntry(line, Comments.parse(buffer)))
+                data.append(SourcelistEntry(line, Comments.parse(buffer), context))
                 buffer = []
             else:
                 buffer.append(line)

specfile/sources.py

@@ -5,14 +5,17 @@
 import re
 import urllib.parse
 from abc import ABC, abstractmethod
-from typing import Iterable, List, Optional, Tuple, Union, cast, overload
+from typing import TYPE_CHECKING, Iterable, List, Optional, Tuple, Union, cast, overload
 
 from specfile.exceptions import DuplicateSourceException
 from specfile.rpm import Macros
 from specfile.sourcelist import Sourcelist, SourcelistEntry
 from specfile.tags import Comments, Tag, Tags
 from specfile.utils import get_filename_from_location
 
+if TYPE_CHECKING:
+    from specfile.specfile import Specfile
+
 
 class Source(ABC):
     """Class that represents a source."""
@@ -218,6 +221,7 @@ def __init__(
         allow_duplicates: bool = False,
         default_to_implicit_numbering: bool = False,
         default_source_number_digits: int = 1,
+        context: Optional["Specfile"] = None,
     ) -> None:
         """
         Constructs a `Sources` object.
@@ -228,6 +232,7 @@ def __init__(
             allow_duplicates: Whether to allow duplicate entries when adding new sources.
             default_to_implicit_numbering: Use implicit numbering (no source numbers) by default.
             default_source_number_digits: Default number of digits in a source number.
+            context: `Specfile` instance that defines the context for macro expansions.
 
         Returns:
             Constructed instance of `Sources` class.
@@ -237,6 +242,7 @@ def __init__(
         self._allow_duplicates = allow_duplicates
         self._default_to_implicit_numbering = default_to_implicit_numbering
         self._default_source_number_digits = default_source_number_digits
+        self._context = context
 
     def __repr__(self) -> str:
         tags = repr(self._tags)
@@ -306,6 +312,11 @@ def __delitem__(self, i: Union[int, slice]) -> None:
             _, container, index = items[i]
             del container[index]
 
+    def _expand(self, s: str) -> str:
+        if self._context:
+            return self._context.expand(s)
+        return Macros.expand(s)
+
     def _get_tags(self) -> List[Tuple[TagSource, Tags, int]]:
         """
         Gets all tag sources.
@@ -474,7 +485,7 @@ def insert(self, i: int, location: str) -> None:
                 name, separator = self._get_tag_format(source, number)
                 container.insert(
                     index,
-                    Tag(name, location, Macros.expand(location), separator, Comments()),
+                    Tag(name, location, self._expand(location), separator, Comments()),
                 )
                 self._deduplicate_tag_names(i)
             else:
@@ -488,7 +499,7 @@ def insert(self, i: int, location: str) -> None:
             index, name, separator = self._get_initial_tag_setup()
             self._tags.insert(
                 index,
-                Tag(name, location, Macros.expand(location), separator, Comments()),
+                Tag(name, location, self._expand(location), separator, Comments()),
             )
 
     def insert_numbered(self, number: int, location: str) -> int:
@@ -522,7 +533,7 @@ def insert_numbered(self, number: int, location: str) -> int:
             i = 0
             index, name, separator = self._get_initial_tag_setup(number)
         self._tags.insert(
-            index, Tag(name, location, Macros.expand(location), separator, Comments())
+            index, Tag(name, location, self._expand(location), separator, Comments())
         )
         self._deduplicate_tag_names(i)
         return i

specfile/specfile.py

@@ -233,7 +233,9 @@ def sources(
         """
         with self.sections() as sections, self.tags(sections.package) as tags:
             sourcelists = [
-                (s, Sourcelist.parse(s)) for s in sections if s.name == "sourcelist"
+                (s, Sourcelist.parse(s, context=self))
+                for s in sections
+                if s.name == "sourcelist"
             ]
             try:
                 yield Sources(
@@ -242,6 +244,7 @@ def sources(
                     allow_duplicates,
                     default_to_implicit_numbering,
                     default_source_number_digits,
+                    context=self,
                 )
             finally:
                 for section, sourcelist in sourcelists:
@@ -267,7 +270,9 @@ def patches(
         """
         with self.sections() as sections, self.tags(sections.package) as tags:
             patchlists = [
-                (s, Sourcelist.parse(s)) for s in sections if s.name == "patchlist"
+                (s, Sourcelist.parse(s, context=self))
+                for s in sections
+                if s.name == "patchlist"
             ]
             try:
                 yield Patches(
@@ -276,6 +281,7 @@ def patches(
                     allow_duplicates,
                     default_to_implicit_numbering,
                     default_source_number_digits,
+                    context=self,
                 )
             finally:
                 for section, patchlist in patchlists:
@@ -572,7 +578,9 @@ class Entity:
         entities.update({k.upper(): v for k, v in entities.items() if v.type == Tag})
 
         def update(value, requested_value):
-            regex, template = ValueParser.construct_regex(value, entities.keys())
+            regex, template = ValueParser.construct_regex(
+                value, entities.keys(), context=self
+            )
             m = regex.match(requested_value)
             if m:
                 d = m.groupdict()

specfile/value_parser.py

@@ -5,12 +5,15 @@
 import re
 from abc import ABC
 from string import Template
-from typing import List, Tuple
+from typing import TYPE_CHECKING, List, Optional, Tuple
 from typing.re import Pattern
 
 from specfile.exceptions import UnterminatedMacroException
 from specfile.rpm import Macros
 
+if TYPE_CHECKING:
+    from specfile.specfile import Specfile
+
 SUBSTITUTION_GROUP_PREFIX = "sub_"
 
 
@@ -227,7 +230,10 @@ def find_macro_end(index):
 
     @classmethod
     def construct_regex(
-        cls, value: str, modifiable_entities: List[str]
+        cls,
+        value: str,
+        modifiable_entities: List[str],
+        context: Optional["Specfile"] = None,
     ) -> Tuple[Pattern, Template]:
         """
         Parses the given value and constructs a regex that allows matching
@@ -250,18 +256,24 @@ def construct_regex(
             value: Value string to parse.
             modifiable_entities: Names of modifiable entities, i.e. local macro definitions
               and tags.
+            context: `Specfile` instance that defines the context for macro expansions.
 
         Returns:
             Tuple in the form of (constructed regex, corresponding template).
         """
 
+        def expand(s):
+            if context:
+                return context.expand(s)
+            return Macros.expand(s)
+
         def flatten(nodes):
             # get rid of conditional macro expansions
             result = []
             for node in nodes:
                 if isinstance(node, ConditionalMacroExpansion):
                     # evaluate the condition
-                    if Macros.expand(f"%{node.prefix}{node.name}"):
+                    if expand(f"%{node.prefix}{node.name}"):
                         result.append(f"%{{{node.prefix}{node.name}:")
                         result.extend(flatten(node.body))
                         result.append("}")
@@ -281,13 +293,13 @@ def flatten(nodes):
             elif isinstance(node, StringLiteral):
                 tokens.append(("v", node.value, ""))
             elif isinstance(node, (ShellExpansion, ExpressionExpansion)):
-                const = Macros.expand(str(node))
+                const = expand(str(node))
                 tokens.append(("c", const, str(node)))
             elif isinstance(node, MacroSubstitution):
                 if node.prefix.count("!") % 2 == 0 and node.name in modifiable_entities:
                     tokens.append(("g", node.name, str(node)))
                 else:
-                    const = Macros.expand(str(node))
+                    const = expand(str(node))
                     tokens.append(("c", const, str(node)))
             elif isinstance(node, EnclosedMacroSubstitution):
                 if (
@@ -297,7 +309,7 @@ def flatten(nodes):
                 ):
                     tokens.append(("g", node.name, str(node)))
                 else:
-                    const = Macros.expand(str(node))
+                    const = expand(str(node))
                     tokens.append(("c", const, str(node)))
 
         def escape(s):

tests/integration/test_specfile.py

@@ -333,3 +333,14 @@ def test_update_tag(spec_macros):
         assert md.minorver.body == "2"
     with spec.sources() as sources:
         assert sources[1].location == "tests-86.tar.xz"
+
+
+def test_multiple_instances(spec_minimal, spec_autosetup):
+    spec1 = Specfile(spec_minimal)
+    spec2 = Specfile(spec_autosetup)
+    spec1.version = "14.2"
+    assert spec2.expanded_version == "0.1"
+    with spec2.sources() as sources:
+        assert sources[0].expanded_location == "test-0.1.tar.xz"
+        sources.append("tests-%{version}.tar.xz")
+        assert sources[1].expanded_location == "tests-0.1.tar.xz"