Add mapcss support for @supports

All rules in `@supports` blocks are dropped unless `-osmoseItemClassLevel` is set.

Also adds tests

mapcss/MapCSSListenerL.py

@@ -10,6 +10,7 @@ class MapCSSListenerL(MapCSSListener):
     # Enter a parse tree produced by MapCSSParser#stylesheet.
     def enterStylesheet(self, ctx:MapCSSParser.StylesheetContext):
         self.rules: List[Dict] = []
+        self.supportCondition = None
 
     # Exit a parse tree produced by MapCSSParser#stylesheet.
     def exitStylesheet(self, ctx:MapCSSParser.StylesheetContext):
@@ -24,7 +25,7 @@ def enterRule_(self, ctx:MapCSSParser.Rule_Context):
 
     # Exit a parse tree produced by MapCSSParser#rule_.
     def exitRule_(self, ctx:MapCSSParser.Rule_Context):
-        self.rules.append({'type': 'rule', 'selectors': self.selectors or self.attribute_selectors, 'declarations': self.declarations})
+        self.rules.append({'type': 'rule', 'selectors': self.selectors or self.attribute_selectors, 'declarations': self.declarations, 'in_supports_declaration': self.supportCondition is not None})
 
 
     # Enter a parse tree produced by MapCSSParser#selector.
@@ -304,3 +305,9 @@ def exitPrimaryExpression(self, ctx:MapCSSParser.PrimaryExpressionContext):
             'derefered': not (not (ctx.OP_MUL())),
             'value': (ctx.v and ctx.v.text) or v['osmtag'] or v['quoted'] or v['regexExpression'][0]
         }
+
+    def exitSupports_rule(self, ctx:MapCSSParser.Supports_ruleContext):
+        self.supportCondition = ctx.supports_condition().getText()
+
+    def exitSupports_block(self, ctx:MapCSSParser.Supports_blockContext):
+        self.supportCondition = None

mapcss/mapcss2osmose.py

@@ -606,6 +606,15 @@ def filter_typeselector_rules(rules):
         rules
     )))
 
+def filter_support_rules(rules):
+    # We don't parse the actual values of @supports
+    # Assume all rules within @supports {} are unsafe unless -osmoseItemClassLevel is set
+    return list(filter(lambda rule:
+        rule.get('_meta') or
+        not rule.get('in_supports_declaration') or
+        next(filter(lambda declaration: declaration.get('property') == '-osmoseItemClassLevel', rule['declarations']), None),
+        rules))
+
 
 class_map: Dict[Optional[str], int] = {}
 class_index = 0
@@ -898,6 +907,7 @@ def compile(inputfile, class_name, mapcss_url = None, only_for = [], not_for = [
     tree = filter_non_productive_rules(tree)
     tree = filter_osmose_none_rules(tree)
     tree = filter_typeselector_rules(tree)
+    tree = filter_support_rules(tree)
     selectors_type = segregate_selectors_type(tree)
 
     global class_, tests, regex_store, set_store

plugins/tests/test_mapcss_parsing_evaluation.validator.mapcss

@@ -429,6 +429,28 @@ node[a][concat(tag("a"), "bc", tag("d")) == "1bc"] {
   assertMatch: "node a=1";
 }
 
+@supports (min-josm-version: 12345) {
+  node[x] {
+    throwWarning: tr("I support supports {0}", "{0.tag}");
+    -osmoseItemClassLevel: "4/96:0/3";
+    assertMatch: "node x=2";
+  }
+}
+@supports not ((min-josm-version: 12345) and ((random-key) or (user-agent: josm))) {
+  node[x] {
+    throwWarning: tr("I support supports {0}", "{0.tag}");
+    -osmoseItemClassLevel: "4/96:1/3";
+    assertMatch: "node x=2";
+    set .supportsSet;
+  }
+  node[y] {
+    throwWarning: "I should be dropped!"; 
+    /* no -osmoseItemClassLevel so we don't know if this rule is safe for Osmose */
+    assertNoMatch: "node y=2";
+    set .thisSetShouldNotBeDefined;
+  }
+}
+
 node[URL_decode("M%C3%A1rio Leopoldo Pereira da C%C3%A2mara") == "Mário Leopoldo Pereira da Câmara"] {
   throwWarning: "test";
   assertMatch: "node x=abcde";