Merge pull request #2606 from Kodiologist/with-pull-out

Fix statement pull-out in multi-item `with`

NEWS.rst

@@ -11,6 +11,8 @@ Bug Fixes
 ------------------------------
 * Fixed a crash on Python 3.12.6.
 * Keyword objects can now be compared to each other with `<` etc.
+* The order of evaluation in multi-item `with`\s now matches that of
+  nested one-item `with`\s.
 * Fixed a bug in which the REPL misinterpreted the symbol `pass`.
 
 0.29.0 (released 2024-05-20)

hy/core/result_macros.py

@@ -1116,22 +1116,39 @@ def compile_with_expression(compiler, expr, root, args, body):
         expr, targets=[name], value=asty.Constant(expr, value=None)
     )
 
+    [args] = args
     ret = Result(stmts=[initial_assign])
     items = []
     was_async = None
     cbody = None
-    for i, (is_async, variable, ctx) in enumerate(args[0]):
+    for i, (is_async, variable, ctx) in enumerate(args):
         is_async = bool(is_async)
         if was_async is None:
             was_async = is_async
         elif is_async != was_async:
             # We're compiling a `with` that mixes synchronous and
             # asynchronous context managers. Python doesn't support
             # this directly, so start a new `with` inside the body.
-            cbody = compile_with_expression(compiler, expr, root, [args[0][i:]], body)
+            cbody = compile_with_expression(compiler, expr, root, [args[i:]], body)
             break
-        ctx = compiler.compile(ctx)
-        ret += ctx
+        if not isinstance(ctx, Result):
+            # In a non-recursive call, `ctx` has not yet been compiled,
+            # and thus is not yet a `Result`.
+            ctx = compiler.compile(ctx)
+            if i == 0:
+                ret += ctx
+            elif ctx.stmts:
+                # We need to include some statements as part of this
+                # context manager, but this `with` already has at
+                # least one prior context manager. So, put our
+                # statements in the body and then start a new `with`.
+                cbody = ctx + compile_with_expression(
+                    compiler,
+                    expr,
+                    root,
+                    [((is_async, variable, ctx), *args[i + 1:])],
+                    body)
+                break
         variable = (
             None
             if variable == Symbol("_")

tests/native_tests/with.hy

@@ -1,7 +1,8 @@
 (import
   asyncio
+  unittest.mock [Mock]
   pytest
-  tests.resources [async-test AsyncWithTest])
+  tests.resources [async-test AsyncWithTest async-exits])
 
 (defn test-context []
   (with [fd (open "tests/resources/text.txt" "r")] (assert fd))
@@ -12,36 +13,43 @@
     (with [fd (open filename "r" :encoding "UTF-8")] (.read fd)))
   (assert (= (read-file "tests/resources/text.txt") "TAARGÜS TAARGÜS\n")))
 
+(setv exits [])
 (defclass WithTest [object]
   (defn __init__ [self val]
-    (setv self.val val)
-    None)
+    (setv self.val val))
 
   (defn __enter__ [self]
     self.val)
 
   (defn __exit__ [self type value traceback]
-    (setv self.val None)))
+    (.append exits self.val)))
 
 (defn test-single-with []
+  (setv (cut exits) [])
   (with [t (WithTest 1)]
     (setv out t))
-  (assert (= out 1)))
+  (assert (= out 1))
+  (assert (= exits [1])))
 
 (defn test-quince-with []
+  (setv (cut exits) [])
   (with [t1 (WithTest 1)  t2 (WithTest 2)  t3 (WithTest 3)  _ (WithTest 4)]
     (setv out [t1 t2 t3]))
-  (assert (= out [1 2 3])))
+  (assert (= out [1 2 3]))
+  (assert (= exits [4 3 2 1])))
 
 (defn [async-test] test-single-with-async []
+  (setv (cut async-exits) [])
   (setv out [])
   (asyncio.run
     ((fn :async []
       (with [:async t (AsyncWithTest 1)]
         (.append out t)))))
-  (assert (= out [1])))
+  (assert (= out [1]))
+  (assert (= async-exits [1])))
 
 (defn [async-test] test-quince-with-async []
+  (setv (cut async-exits) [])
   (setv out [])
   (asyncio.run
     ((fn :async []
@@ -51,9 +59,11 @@
           :async t3 (AsyncWithTest 3)
           :async _ (AsyncWithTest 4)]
         (.extend out [t1 t2 t3])))))
-  (assert (= out [1 2 3])))
+  (assert (= out [1 2 3]))
+  (assert (= async-exits [4 3 2 1])))
 
 (defn [async-test] test-with-mixed-async []
+  (setv (cut exits) [])
   (setv out [])
   (asyncio.run
     ((fn :async []
@@ -97,3 +107,17 @@
   (setv w (with [(SuppressZDE)] (.append l w) (/ 1 0) 5))
   (assert (is w None))
   (assert (= l [7])))
+
+(defn test-statements []
+
+  (setv m (Mock))
+  (with [t (do (m) (WithTest 2))]
+    (setv out t))
+  (assert (= m.call-count 1))
+  (assert (= out 2))
+
+  ; https://github.com/hylang/hy/issues/2605
+  (with [t1 (WithTest 1)  t2 (do (setv foo t1) (WithTest 2))]
+    (setv out [t1 t2]))
+  (assert (= out [1 2]))
+  (assert (= foo 1)))

tests/resources/__init__.py

@@ -19,6 +19,7 @@ def function_with_a_dash():
 )
 
 
+async_exits = []
 class AsyncWithTest:
     def __init__(self, val):
         self.val = val
@@ -27,7 +28,7 @@ async def __aenter__(self):
         return self.val
 
     async def __aexit__(self, exc_type, exc, traceback):
-        self.val = None
+        async_exits.append(self.val)
 
 
 async def async_loop(items):