Implement regular expression search for context (#272)

Support new operator `~` for matching patterns and `!~` for
negative matching patterns in the context rules.

Fix #226.

Author: psss

docs/context.rst

@@ -47,7 +47,7 @@ supported operators consult the following grammar outline::
     expression ::= 'true' | 'false'
     dimension ::= [[:alnum:]]+
     binary_operator ::= '==' | '!=' | '<' | '<=' | '>' | '>=' |
-        '~=' | '~!=' | '~<' | '~<=' | '~>' | '~>='
+        '~=' | '~!=' | '~<' | '~<=' | '~>' | '~>=' | '~' | '!~'
     unary_operator ::= 'is defined' | 'is not defined'
     values ::= value (',' value)*
     value ::= [[:alnum:]]+
@@ -65,6 +65,12 @@ Let's demonstrate the syntax on a couple of real-life examples::
     # check whether a dimension is defined
     collection is not defined
 
+    # search dimension value for a regular expression
+    initiator ~ .*-ci
+
+    # make sure that the value does not match given regular expression
+    arch !~ ppc64.*
+
     # disable adjust rule (e.g. during debugging / experimenting)
     false and <original rule>
 

docs/releases.rst

@@ -5,6 +5,14 @@
 ======================
 
 
+fmf-1.6.0
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+In order to search :ref:`context` dimension values using regular
+expressions, it is now possible to use operator ``~`` for matching
+patterns and operator ``!~`` for non matching patterns.
+
+
 fmf-1.5.0
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 

fmf/context.py

@@ -34,15 +34,18 @@ class InvalidContext(Exception):
 class ContextValue:
     """ Value for dimension """
 
-    def __init__(self, origin):
+    def __init__(self, raw):
         """
         ContextValue("foo-1.2.3")
         ContextValue(["foo", "1", "2", "3"])
         """
-        if isinstance(origin, (tuple, list)):
-            self._to_compare = tuple(origin)
+        if isinstance(raw, (tuple, list)):
+            self._to_compare = tuple(raw)
         else:
-            self._to_compare = self._split_to_version(origin)
+            self._to_compare = self._split_to_version(raw)
+
+        # Store the original string for regexp processing
+        self.raw = raw
 
     def __eq__(self, other):
         if isinstance(other, self.__class__):
@@ -238,6 +241,22 @@ def comparator(dimension_value, it_val):
 
         return self._op_core(dimension_name, values, comparator)
 
+    def _op_match(self, dimension_name, values):
+        """ '~' operator, regular expression matches """
+
+        def comparator(dimension_value, it_val):
+            return re.search(it_val.raw, dimension_value.raw) is not None
+
+        return self._op_core(dimension_name, values, comparator)
+
+    def _op_not_match(self, dimension_name, values):
+        """ '~' operator, regular expression does not match """
+
+        def comparator(dimension_value, it_val):
+            return re.search(it_val.raw, dimension_value.raw) is None
+
+        return self._op_core(dimension_name, values, comparator)
+
     def _op_minor_eq(self, dimension_name, values):
         """ '~=' operator """
 
@@ -371,6 +390,8 @@ def _op_core(self, dimension_name, values, comparator):
         "~>=": _op_minor_greater_or_equal,
         ">": _op_greater,
         "~>": _op_minor_greater,
+        "~": _op_match,
+        "!~": _op_not_match,
         }
 
     # Triple expression: dimension operator values
@@ -379,7 +400,7 @@ def _op_core(self, dimension_name, values, comparator):
         r"(\w+)"
         + r"\s*("
         + r"|".join(
-            set(operator_map.keys()) - {"is defined", "is not defined"})
+            [key for key in operator_map if key not in ["is defined", "is not defined"]])
         + r")\s*"
         + r"([^=].*)")
     # Double expression: dimension operator

tests/unit/test_context.py

@@ -282,6 +282,31 @@ def test_case_insensitive(self):
         assert python.matches("component > python3-3.7")
         assert python.matches("component < PYTHON3-3.9")
 
+    def test_regular_expression_matching(self):
+        """ Matching regular expressions """
+
+        assert Context(distro="fedora-42").matches("distro ~ ^fedora-42$")
+        assert Context(distro="fedora-42").matches("distro ~ fedora")
+        assert Context(distro="fedora-42").matches("distro ~ fedora|rhel")
+        assert Context(distro="fedora-42").matches("distro ~ fedora-4.*")
+        assert not Context(distro="fedora-42").matches("distro ~ fedora-3.*")
+        assert not Context(distro="fedora-42").matches("distro ~ ubuntu")
+
+        assert Context(arch="ppc64").matches("arch ~ ppc64.*")
+        assert Context(arch="ppc64le").matches("arch ~ ppc64.*")
+        assert not Context(arch="ppc64le").matches("arch ~ ppc64$")
+
+        assert not Context(distro="fedora-42").matches("distro !~ ^fedora-42$")
+        assert not Context(distro="fedora-42").matches("distro !~ fedora")
+        assert not Context(distro="fedora-42").matches("distro !~ fedora|rhel")
+        assert not Context(distro="fedora-42").matches("distro !~ fedora-4.*")
+        assert Context(distro="fedora-42").matches("distro !~ fedora-3.*")
+        assert Context(distro="fedora-42").matches("distro !~ ubuntu")
+
+        assert not Context(arch="ppc64").matches("arch !~ ppc64.*")
+        assert not Context(arch="ppc64le").matches("arch !~ ppc64.*")
+        assert Context(arch="ppc64le").matches("arch !~ ppc64$")
+
 
 class TestContextValue:
     impossible_split = ["x86_64", "ppc64", "fips", "errata"]