[core] Clear PATH cache when mutating PATH

Mem.SetNamed sets self.clear_path_cache every time 'PATH' is
modified. SearchPath checks for self.mem.clear_path_cache on every
CachedLookup, clearing the cache if necessary.

Fixes: #2445

Signed-off-by: Andrii Sultanov <[email protected]>

Author: last-genius

core/executor.py

@@ -128,7 +128,7 @@ def _RewriteExternToBuiltin(argv):
 
     Why hidden in OSH?  Because regex engines can have MINOR syntax
     differences, like []] for char classes.  But it could be ON in YSH,
-    specifically so you can AVOID those differences!  
+    specifically so you can AVOID those differences!
 
     Meh: explicit builtin grep / builtin sed is better.  Make a note about
     performance in doc/ref.
@@ -246,6 +246,10 @@ def LookupReflect(self, name, do_all):
     def CachedLookup(self, name):
         # type: (str) -> Optional[str]
         #log('name %r', name)
+        if self.mem.clear_path_cache:
+            self.ClearCache()
+            self.mem.clear_path_cache = False
+
         if name in self.cache:
             return self.cache[name]
 

core/state.py

@@ -1385,6 +1385,8 @@ def __init__(
         from core import sh_init
         self.env_config = sh_init.EnvConfig(self, defaults)
 
+        self.clear_path_cache = False  # a hack. Read and modified by SearchPath
+
     def __repr__(self):
         # type: () -> str
         parts = []  # type: List[str]
@@ -2023,6 +2025,12 @@ def SetNamed(self, lval, val, which_scopes, flags=0):
         This can be used to FLIP flags, while NOT changing the variable.  Or it
         can also be used to initialize?
         """
+
+        # Hack: let SearchPath know it needs to reset the path
+        # cache before looking up a command
+        if lval.name == 'PATH':
+            self.clear_path_cache = True
+
         if flags & SetNameref or flags & ClearNameref:
             # declare -n ref=x  # refers to the ref itself
             cell, var_frame = self._ResolveNameOnly(lval.name, which_scopes)