Merge pull request #225 from benfred/fix_dump_locals

Fix dump --locals

src/python_data_access.rs

@@ -148,9 +148,14 @@ const PY_TPFLAGS_STRING_SUBCLASS: usize = 1 << 28;
 const PY_TPFLAGS_DICT_SUBCLASS: usize =    1 << 29;
 
 /// Converts a python variable in the other process to a human readable string
-/// similar to stringify_pyobject - but has knows the type of the python interpreter
 pub fn format_variable<I>(process: &remoteprocess::Process, version: &Version, addr: usize, max_length: isize)
         -> Result<String, Error> where I: InterpreterState {
+    // We need at least 5 characters remaining for all this code to work, replace with an ellipsis if
+    // we're out of space
+    if max_length <= 5 {
+        return Ok("...".to_owned());
+    }
+
     let value: I::Object = process.copy_struct(addr)?;
     let value_type = process.copy_pointer(value.ob_type())?;
 
@@ -229,13 +234,13 @@ pub fn format_variable<I>(process: &remoteprocess::Process, version: &Version, a
         let mut values = Vec::new();
         let mut remaining = max_length - 2;
         for i in 0..object.size() {
+            let value_addr: *mut I::Object = process.copy_struct(object.address(addr, i))?;
+            let value = format_variable::<I>(process, version, value_addr as usize, remaining)?;
+            remaining -= value.len() as isize + 2;
             if remaining <= 5 {
                 values.push("...".to_owned());
                 break;
             }
-            let value_addr: *mut I::Object = process.copy_struct(object.address(addr, i))?;
-            let value = format_variable::<I>(process, version, value_addr as usize, remaining)?;
-            remaining -= value.len() as isize + 2;
             values.push(value);
         }
         format!("({})", values.join(", "))

src/stack_trace.rs

@@ -50,7 +50,7 @@ pub struct LocalVariable {
 }
 
 /// Given an InterpreterState, this function returns a vector of stack traces for each thread
-pub fn get_stack_traces<I>(interpreter: &I, process: &Process) -> Result<(Vec<StackTrace>), Error>
+pub fn get_stack_traces<I>(interpreter: &I, process: &Process) -> Result<Vec<StackTrace>, Error>
         where I: InterpreterState {
     // TODO: deprecate this method
     let mut ret = Vec::new();

tests/integration_test.rs

@@ -194,7 +194,7 @@ fn test_local_vars() {
     let frame = &trace.frames[0];
     let locals = frame.locals.as_ref().unwrap();
 
-    assert_eq!(locals.len(), 8);
+    assert_eq!(locals.len(), 9);
 
     let arg1 = &locals[0];
     assert_eq!(arg1.name, "arg1");
@@ -235,6 +235,10 @@ fn test_local_vars() {
     assert_eq!(local5.name, "local5");
     assert!(!local5.arg);
 
+    let local6 = &locals[8];
+    assert_eq!(local6.name, "local6");
+    assert!(!local6.arg);
+
     // we only support dictionary lookup on python 3.6+ right now
     if runner.spy.version.major == 3 && runner.spy.version.minor >= 6 {
         assert_eq!(local5.repr, Some("{\"a\": False, \"b\": (1, 2, 3)}".to_owned()));

tests/scripts/local_vars.py

@@ -7,7 +7,10 @@ def local_variable_lookup(arg1="foo", arg2=None, arg3=True):
     local3 = 123456789123456789
     local4 = 3.1415
     local5 = {"a": False, "b": (1, 2, 3)}
+    # https://github.com/benfred/py-spy/issues/224
+    local6 = ("-" * 115, {"key": {"key": {"key": "value"}}})
     time.sleep(100000)
 
+
 if __name__ == "__main__":
     local_variable_lookup()