oelint.vars.layerconf: add new rule

to check that only layer.conf specific variables
are set in a layer.conf

Relates to #607

Signed-off-by: Konrad Weihmann <[email protected]>

docs/wiki/oelint.vars.layerconf.md

@@ -0,0 +1,31 @@
+# oelint.vars.layerconf
+
+severity: warn
+
+## Example
+
+```
+IMAGE_INSTALL += "my-recipe"
+```
+
+## Why is this bad?
+
+A setting from a ``layer.conf`` becomes effective, just by including the layer into the build.
+Adding settings beyond the pure layer configuration should be reserved for machine, distro or image configuration.
+
+## Ways to fix it
+
+Only the following variables should be set as part of a ``layer.conf``
+
+- BBFILES
+- BBFILES_DYNAMIC
+- BBFILE_COLLECTIONS
+- BBFILE_PATTERN_.*
+- BBFILE_PRIORITY_.*
+- BBPATH
+- HOSTTOOLS_NONFATAL
+- LAYERDEPENDS_.*
+- LAYERRECOMMENDS_.*
+- LAYERSERIES_COMPAT_.*
+- LAYERVERSION_.*
+- LICENSE_PATH

oelint_adv/rule_base/rule_vars_layerconf.py

@@ -0,0 +1,43 @@
+import fnmatch
+from typing import List, Tuple
+
+from oelint_parser.cls_item import Variable
+from oelint_parser.cls_stash import Stash
+from oelint_parser.rpl_regex import RegexRpl
+
+from oelint_adv.cls_rule import Rule
+
+
+class VarsLayerConf(Rule):
+    def __init__(self) -> None:
+        self.good = [
+            r'BBFILES',
+            r'BBFILES_DYNAMIC',
+            r'BBFILE_COLLECTIONS',
+            r'BBFILE_PATTERN_.*',
+            r'BBFILE_PRIORITY_.*',
+            r'BBPATH',
+            r'HOSTTOOLS_NONFATAL',
+            r'LAYERDEPENDS_.*',
+            r'LAYERRECOMMENDS_.*',
+            r'LAYERSERIES_COMPAT_.*',
+            r'LAYERVERSION_.*',
+            r'LICENSE_PATH',
+        ]
+
+        super().__init__(id='oelint.vars.layerconf',
+                         severity='warn',
+                         message='{var} should not be set as part of a layer configuration')
+
+    def check(self, _file: str, stash: Stash) -> List[Tuple[str, int, str]]:
+        res = []
+        items: List[Variable] = stash.GetItemsFor(filename=_file, classifier=Variable.CLASSIFIER,
+                                                  attribute=Variable.ATTR_VAR)
+
+        for i in items:
+            if not fnmatch.fnmatch(i.Origin, '*/layer.conf'):
+                continue
+            if not any(RegexRpl.match(x, i.VarName) for x in self.good):
+                res += self.finding(_file, i.Line,
+                                    self.Msg.format(var=i.VarName))
+        return res