Resolve test_inspect bytecode parity gaps by youknowone · Pull Request #7926 · RustPython/RustPython

🌐 Web query:

In CPython, does the compiler always store the synthetic classcellinto the class locals namespace, even when the class body declaresglobal classcellornonlocal classcell?

💡 Result:

No—CPython does not always end up storing the synthetic classcell into the class-body locals namespace when the class body declares global classcell or nonlocal classcell. In CPython, the zero-argument super() mechanism is implemented by injecting a hidden class / classcell cell during compilation, but CPython also standardizes behavior so that class and (in 3.6+) classcell do not show up in the class locals while the class body executes [1]. Additionally, the generator/symbol-table machinery for class/classcell interacts “strangely” with explicit nonlocal class in nested namespaces: the injection behaves like a closure/free variable and can be accessed via nonlocal from a nested class, without being treated as a normal local in the class-body locals mapping [1]. This directly implies that declaring nonlocal classcell (analogous to the class case discussed) prevents classcell from being stored like a regular local entry in the class locals namespace. So, when you explicitly declare global classcell or nonlocal classcell, CPython’s compiler/symbol-table handling will not necessarily (and in these cases generally does not) place the synthetic classcell into the class locals mapping the way it would for a normal class body without such declarations; instead the injected cell remains hidden/handled specially for LOAD_BUILD_CLASS and zero-argument super() semantics [1].

Citations:

• 1: https://bugs.python.org/issue28891

🏁 Script executed:

# First, check the file size and read the relevant sections
wc -l crates/codegen/src/compile.rs

Repository: RustPython/RustPython

Length of output: 101

🏁 Script executed:

# Read around line 6717
sed -n '6710,6725p' crates/codegen/src/compile.rs

Repository: RustPython/RustPython

Length of output: 690

🏁 Script executed:

# Read around line 6731
sed -n '6724,6738p' crates/codegen/src/compile.rs

Repository: RustPython/RustPython

Length of output: 557

🏁 Script executed:

# Find the store_name method definition to understand its behavior
rg -n "fn store_name" crates/codegen/src/compile.rs | head -5

Repository: RustPython/RustPython

Length of output: 134

🏁 Script executed:

# Search for any special handling of __classcell__ or __classdictcell__
rg -n "__classcell__|__classdictcell__" crates/codegen/src/compile.rs

Repository: RustPython/RustPython

Length of output: 661

🏁 Script executed:

# Read the store_name implementation
sed -n '3146,3160p' crates/codegen/src/compile.rs

Repository: RustPython/RustPython

Length of output: 684

🏁 Script executed:

# Search for any method that might do unconditional class-local stores
rg -n "store_.*local|store_cell|STORE_DEREF|STORE_GLOBAL" crates/codegen/src/compile.rs | head -20

Repository: RustPython/RustPython

Length of output: 380

🏁 Script executed:

# Get broader context around line 6717 - understand the class body compilation
sed -n '6690,6745p' crates/codegen/src/compile.rs

Repository: RustPython/RustPython

Length of output: 1960

🏁 Script executed:

# Find compile_name implementation
rg -n "fn compile_name" crates/codegen/src/compile.rs

Repository: RustPython/RustPython

Length of output: 154

🏁 Script executed:

# Search for enum NameUsage to understand Store variant
rg -n "enum NameUsage" crates/codegen/src/compile.rs -A 10

Repository: RustPython/RustPython

Length of output: 386

🏁 Script executed:

# Look for direct instruction emitters that might bypass name resolution
rg -n "Instruction::Store|PseudoInstruction::Store" crates/codegen/src/compile.rs | head -20

Repository: RustPython/RustPython

Length of output: 1639

🏁 Script executed:

# Check how __static_attributes__ is handled (line 6707 shows it uses store_name too)
# Let's see if there's any special handling for class protocol names
rg -n "__staticattr|__firstlineno__|__module__|__qualname__" crates/codegen/src/compile.rs | head -20

Repository: RustPython/RustPython

Length of output: 1309

🏁 Script executed:

# Confirm that __classdict__ uses direct STORE_DEREF
sed -n '6648,6656p' crates/codegen/src/compile.rs

Repository: RustPython/RustPython

Length of output: 502

🏁 Script executed:

# Check what the exact instruction types are for these stores
rg -n "Instruction::(StoreDeref|StoreName|StoreGlobal|StoreFast)" crates/codegen/src/compile.rs | grep -E "6(6|7)[0-9]{2}:" | head -20

Repository: RustPython/RustPython

Length of output: 234