Don't panic when can't __del__ object

coolreader18 · coolreader18 · commit fd87c238fca2 · 2021-03-14T12:49:59.000-05:00
diff --git a/vm/src/lib.rs b/vm/src/lib.rs
@@ -54,7 +54,7 @@ pub mod frame;
 mod frozen;
 pub mod function;
 pub mod import;
-mod iterator;
+pub mod iterator;
 mod py_io;
 pub mod py_serde;
 pub mod pyobject;
diff --git a/vm/src/pyobjectrc.rs b/vm/src/pyobjectrc.rs
@@ -307,7 +307,7 @@ impl Drop for PyObjectRef {
         // CPython-compatible drop implementation
         let zelf = self.clone();
         if let Some(del_slot) = self.class().mro_find_map(|cls| cls.slots.del.load()) {
-            crate::vm::thread::with_vm(&zelf, |vm| {
+            let ret = crate::vm::thread::with_vm(&zelf, |vm| {
                 if let Err(e) = del_slot(&zelf, vm) {
                     // exception in del will be ignored but printed
                     print!("Exception ignored in: ",);
@@ -327,6 +327,9 @@ impl Drop for PyObjectRef {
                     }
                 }
             });
+            if ret.is_none() {
+                warn!("couldn't run __del__ method for object")
+            }
         }
 
         // __del__ might have resurrected the object at this point, but that's fine,
diff --git a/vm/src/vm.rs b/vm/src/vm.rs
@@ -86,7 +86,7 @@ pub(crate) mod thread {
         })
     }
 
-    pub fn with_vm<F, R>(obj: &PyObjectRef, f: F) -> R
+    pub fn with_vm<F, R>(obj: &PyObjectRef, f: F) -> Option<R>
     where
         F: Fn(&VirtualMachine) -> R,
     {
@@ -101,14 +101,12 @@ pub(crate) mod thread {
                     debug_assert!(vm_owns_obj(x));
                     x
                 }
-                Err(mut others) => others
-                    .find(|x| vm_owns_obj(*x))
-                    .unwrap_or_else(|| panic!("can't get a vm for {:?}; none on stack", obj)),
+                Err(mut others) => others.find(|x| vm_owns_obj(*x))?,
             };
             // SAFETY: all references in VM_STACK should be valid, and should not be changed or moved
             // at least until this function returns and the stack unwinds to an enter_vm() call
             let vm = unsafe { intp.as_ref() };
-            f(vm)
+            Some(f(vm))
         })
     }
 }

Original file line number	Diff line number	Diff line change
`@@ -307,7 +307,7 @@ impl Drop for PyObjectRef {`
`307`	`307`	`// CPython-compatible drop implementation`
`308`	`308`	`let zelf = self.clone();`
`309`	`309`	`if let Some(del_slot) = self.class().mro_find_map(\|cls\| cls.slots.del.load()) {`
`310`		`- crate::vm::thread::with_vm(&zelf, \|vm\| {`
	`310`	`+ let ret = crate::vm::thread::with_vm(&zelf, \|vm\| {`
`311`	`311`	`if let Err(e) = del_slot(&zelf, vm) {`
`312`	`312`	`// exception in del will be ignored but printed`
`313`	`313`	`print!("Exception ignored in: ",);`
`@@ -327,6 +327,9 @@ impl Drop for PyObjectRef {`
`327`	`327`	`}`
`328`	`328`	`}`
`329`	`329`	`});`
	`330`	`+ if ret.is_none() {`
	`331`	`+ warn!("couldn't run __del__ method for object")`
	`332`	`+ }`
`330`	`333`	`}`
`331`	`334`
`332`	`335`	`// __del__ might have resurrected the object at this point, but that's fine,`
Original file line number	Diff line number	Diff line change
`@@ -86,7 +86,7 @@ pub(crate) mod thread {`
`86`	`86`	`})`
`87`	`87`	`}`
`88`	`88`
`89`		`- pub fn with_vm<F, R>(obj: &PyObjectRef, f: F) -> R`
	`89`	`+ pub fn with_vm<F, R>(obj: &PyObjectRef, f: F) -> Option<R>`
`90`	`90`	`where`
`91`	`91`	`F: Fn(&VirtualMachine) -> R,`
`92`	`92`	`{`
`@@ -101,14 +101,12 @@ pub(crate) mod thread {`
`101`	`101`	`debug_assert!(vm_owns_obj(x));`
`102`	`102`	`x`
`103`	`103`	`}`
`104`		`- Err(mut others) => others`
`105`		`- .find(\|x\| vm_owns_obj(*x))`
`106`		`- .unwrap_or_else(\|\| panic!("can't get a vm for {:?}; none on stack", obj)),`
	`104`	`+ Err(mut others) => others.find(\|x\| vm_owns_obj(*x))?,`
`107`	`105`	`};`
`108`	`106`	`// SAFETY: all references in VM_STACK should be valid, and should not be changed or moved`
`109`	`107`	`// at least until this function returns and the stack unwinds to an enter_vm() call`
`110`	`108`	`let vm = unsafe { intp.as_ref() };`
`111`		`- f(vm)`
	`109`	`+ Some(f(vm))`
`112`	`110`	`})`
`113`	`111`	`}`
`114`	`112`	`}`