vadimcn
Rust synth summary KeyError
OS:
% uname -a
Darwin BK-****** 22.4.0 Darwin Kernel Version 22.4.0: Mon Mar 6 20:59:28 PST 2023; root:xnu-8796.101.5~3/RELEASE_ARM64_T6000 arm6
% gcc -dumpmachine
arm64-apple-darwin22.4.
VSCode version:
I am actually using nvim:
% nvim --version
NVIM v0.9.0
Build type: Release
LuaJIT 2.1.0-beta3
CodeLLDB version: 1.9.2
Compiler
% rustc --version
rustc 1.68.2 (9eb3afe9e 2023-03-27
Debugee
Rust binary. A silly, simple program:
fn main() {
let s = Some("");
if s.is_some() {
let s1 = s.unwrap();
println!("s1: {}", s1);
}
println!("Hello, world!");
}
The Problem
While I am able to attach to the debugger, set breakpoints, and print variable names, on startup and each time I print a variable, I get Python stacktrace from a KeyError on get_synth_summary in formatters/rust.py for obj id 4294967295.
Console is in 'commands' mode, prefix expressions with '?'. Executing script: initCommands Launching: /Users/***/Code/nlsp-settings-demo/target/debug/nlsp-settings-demo Launched process 83874[debug-adapter stderr] ERROR(Python) 15:16:35 formatters.rust: 4294967295 Traceback (most recent call last): File "/Users//.vscode/extensions/vadimcn.vscode-lldb-1.9.2/formatters/rust.py", line 105, in get_synth_summary summary = RustSynthProvider.synth_by_id[obj_id].get_summary() File "/Users//.vscode/extensions/vadimcn.vscode-lldb-1.9.2/lldb/lib/python3.9/weakref.py", line 134, in getitem o = self.datakey KeyError: 4294967295
[debug-adapter stderr] Traceback (most recent call last): File "/Users//.vscode/extensions/vadimcn.vscode-lldb-1.9.2/formatters/rust.py", line 85, in summary_fn def summary_fn(valobj, dict): return get_synth_summary(synth_class, valobj, dict) File "/Users//.vscode/extensions/vadimcn.vscode-lldb-1.9.2/formatters/rust.py", line 105, in get_synth_summary summary = RustSynthProvider.synth_by_id[obj_id].get_summary() File "/Users/***/.vscode/extensions/vadimcn.vscode-lldb-1.9.2/lldb/lib/python3.9/weakref.py", line 134, in getitem o = self.datakey KeyError: 4294967295
[debug-adapter stderr] ERROR(Python) 15:16:35 formatters.rust: 4294967295 Traceback (most recent call last): File "/Users//.vscode/extensions/vadimcn.vscode-lldb-1.9.2/formatters/rust.py", line 105, in get_synth_summary summary = RustSynthProvider.synth_by_id[obj_id].get_summary() File "/Users//.vscode/extensions/vadimcn.vscode-lldb-1.9.2/lldb/lib/python3.9/weakref.py", line 134, in getitem o = self.datakey KeyError: 4294967295 Traceback (most recent call last): File "/Users//.vscode/extensions/vadimcn.vscode-lldb-1.9.2/formatters/rust.py", line 85, in summary_fn def summary_fn(valobj, dict): return get_synth_summary(synth_class, valobj, dict) File "/Users//.vscode/extensions/vadimcn.vscode-lldb-1.9.2/formatters/rust.py", line 105, in get_synth_summary summary = RustSynthProvider.synth_by_id[obj_id].get_summary() File "/Users/***/.vscode/extensions/vadimcn.vscode-lldb-1.9.2/lldb/lib/python3.9/weakref.py", line 134, in getitem o = self.datakey KeyError: 4294967295
Also, it may be useful to know that I am following the snippets in the nvim-dap Wiki for Rust lldb-vscode.
dap.configurations.rust = {
{
-- ... the previous config goes here ...,
initCommands = function()
-- Find out where to look for the pretty printer Python module
local rustc_sysroot = vim.fn.trim(vim.fn.system('rustc --print sysroot'))
local script_import = 'command script import "' .. rustc_sysroot .. '/lib/rustlib/etc/lldb_lookup.py"'
local commands_file = rustc_sysroot .. '/lib/rustlib/etc/lldb_commands'
local commands = {}
local file = io.open(commands_file, 'r')
if file then
for line in file:lines() do
table.insert(commands, line)
end
file:close()
end
table.insert(commands, 1, script_import)
return commands
end,
-- ...,
}
Thanks for the patience and not closing the issue. I pivoted over to another project for a while.
What exactly do you mean by "print a variable"?
Using nvim-dap-ui:
dap> ?program_path
{...}
: <error: No value>
[raw]: core::option::Option<alloc::string::String>::Some
Beautiful, this is great, thanks.
Can you please provide a verbose log?
Console is in 'commands' mode, prefix expressions with '?'.
Executing script: initCommands
[debug-adapter stderr] INFO(Python) 14:35:22 formatters: Initializing
[debug-adapter stderr] INFO(Python) 14:35:22 formatters.rust: Initializing
Launching: /Users/xxx/Code/path/to/my/exec with my args
Launched process 74911
[debug-adapter stderr] [ERROR codelldb::debug_session] [529] no available capacity
[debug-adapter stderr] [ERROR codelldb::debug_session] [529] no available capacity
[debug-adapter stderr] [ERROR codelldb::debug_session] [529] no available capacity
[debug-adapter stderr] [ERROR codelldb::debug_session] [529] no available capacity
[ERROR codelldb::debug_session] [529] no available capacity
[ERROR codelldb::debug_session] [529] no available capacity
[debug-adapter stderr] [ERROR codelldb::debug_session] [529] no available capacity
# The following repeats 12 times:
[debug-adapter stderr] ERROR(Python) 14:35:26 formatters.rust: 4294967295
Traceback (most recent call last):
File "/Users/xxx/.vscode/extensions/vadimcn.vscode-lldb-1.9.2/formatters/rust.py", line 105, in get_synth_summary
summary = RustSynthProvider.synth_by_id[obj_id].get_summary()
File "/Users/xxx/.vscode/extensions/vadimcn.vscode-lldb-1.9.2/lldb/lib/python3.9/weakref.py", line 134, in __getitem__
o = self.data[key]()
KeyError: 4294967295
[debug-adapter stderr] Traceback (most recent call last):
File "/Users/xxx/.vscode/extensions/vadimcn.vscode-lldb-1.9.2/formatters/rust.py", line 85, in summary_fn
def summary_fn(valobj, dict): return get_synth_summary(synth_class, valobj, dict)
File "/Users/xxx/.vscode/extensions/vadimcn.vscode-lldb-1.9.2/formatters/rust.py", line 105, in get_synth_summary
summary = RustSynthProvider.synth_by_id[obj_id].get_summary()
File "/Users/xxx/.vscode/extensions/vadimcn.vscode-lldb-1.9.2/lldb/lib/python3.9/weakref.py", line 134, in __getitem__
o = self.data[key]()
KeyError: 4294967295
# end repeats
FWIW, I am running in nvim. I was able to replicate the verbose logging in VSCode by setting RUST_LOG=error,codelldb=debug: https://github.com/vadimcn/codelldb/blob/f4b6ad6dfc20a31da922146b78cbea9543997e5d/extension/novsc/adapter.ts#L42
I was running into this too, and here's my findings for my case:
https://github.com/vadimcn/codelldb/blob/05502bf75e4e7878a99b0bf0a7a81bba2922cbe3/formatters/rust.py#L115
tries to retrieve an Index of a child with name, using the LLDB function uint32_t SBValue::GetIndexOfChildWithName, as defined at
https://github.com/llvm/llvm-project/blob/780a5116ba68ec8c53b65008b3407479478b2d5e/lldb/source/API/SBValue.cpp#L683
where we can see that UINT32_MAX, i.e. -1, is returned as a fallback value - It's essentially an error code.
There is no check for this error value before
https://github.com/vadimcn/codelldb/blob/05502bf75e4e7878a99b0bf0a7a81bba2922cbe3/formatters/rust.py#L116
Leading it to try to index on an error code.
In my case, the parent value (valobj) seems be either core::option::Option, or core::result::Result. In both cases, both options (Some and None for Option, Ok and Err for Result) throw this error.
I thought this might be generalised over all Enums because of this, but user-defined enums seem to be perfectly fine. It might be that it's enums with generics, but I haven't had the time to investigate that yet.
Workaround Update (@erichulburd): It seems to be possible to resolve this issue by adding
type summary add -F lldb_lookup.summary_lookup -e -x -h "^(core::([a-z_]+::)+)Option<.+>::(Some|None)$" --category Rust
type summary add -F lldb_lookup.summary_lookup -e -x -h "^(core::([a-z_]+::)+)Result<.+>::(Ok|Err)$" --category Rust
(or something that equivalently matches any FQN of Option<T>::(Some|None) and Result<T, E>::(Ok|Err))
to $(rustc --print sysroot)/lib/rustlib/etc/lldb_commands.
This means it should probably be resolved in https://github.com/rust-lang/rust/blob/master/src/etc/lldb_commands rather than it being a codelldb issue. I will look into it a bit more, and then likely make an issue and PR there
Alright, one more. Been at this all day:
The snippets me and @erichulburd have been using are only for lldb-vscode, which requires an external formatter for the Rust types, provided by the rust project.
codelldb has its own formatter, and does not require these scripts.
I think this ticket can be closed as the issue boils down to "Using configs meant for a different tool breaks this tool"