Improve panic reports

Max Brunsfeld created

* Add an 'identifying_backtrace' field that only contains symbols in our
  codebase, which can be used for better deduplication.
* In the main backtrace, include file and line numbers for all symbols
  in our codebase

Change summary

crates/zed/src/main.rs | 85 ++++++++++++++++++++++++++++++++++++-------
1 file changed, 70 insertions(+), 15 deletions(-)

Detailed changes

crates/zed/src/main.rs 🔗

@@ -32,6 +32,7 @@ use std::{
     ffi::OsStr,
     fs::OpenOptions,
     io::Write as _,
+    ops::Not,
     os::unix::prelude::OsStrExt,
     panic,
     path::{Path, PathBuf},
@@ -371,13 +372,12 @@ struct Panic {
     #[serde(skip_serializing_if = "Option::is_none")]
     location_data: Option<LocationData>,
     backtrace: Vec<String>,
-    // TODO
-    // stripped_backtrace: String,
     release_channel: String,
     os_name: String,
     os_version: Option<String>,
     architecture: String,
     panicked_on: u128,
+    identifying_backtrace: Option<Vec<String>>,
 }
 
 #[derive(Serialize)]
@@ -396,18 +396,73 @@ fn init_panic_hook(app: &App) {
         let app_version = ZED_APP_VERSION
             .or_else(|| platform.app_version().ok())
             .map_or("dev".to_string(), |v| v.to_string());
-        let backtrace = Backtrace::new();
 
         let thread = thread::current();
         let thread = thread.name().unwrap_or("<unnamed>");
 
-        let payload = match info.payload().downcast_ref::<&'static str>() {
-            Some(s) => *s,
-            None => match info.payload().downcast_ref::<String>() {
-                Some(s) => &**s,
-                None => "Box<Any>",
-            },
-        };
+        let payload = info.payload();
+        let payload = None
+            .or_else(|| payload.downcast_ref::<&str>().map(|s| s.to_string()))
+            .or_else(|| payload.downcast_ref::<String>().map(|s| s.clone()))
+            .unwrap_or_else(|| "Box<Any>".to_string());
+
+        let backtrace = Backtrace::new();
+        let backtrace = backtrace
+            .frames()
+            .iter()
+            .filter_map(|frame| {
+                let symbol = frame.symbols().first()?;
+                let path = symbol.filename()?;
+                Some((path, symbol.lineno(), format!("{:#}", symbol.name()?)))
+            })
+            .collect::<Vec<_>>();
+
+        let this_file_path = Path::new(file!());
+
+        // Find the first frame in the backtrace for this panic hook itself. Exclude
+        // that frame and all frames before it.
+        let mut start_frame_ix = 0;
+        let mut codebase_root_path = None;
+        for (ix, (path, _, _)) in backtrace.iter().enumerate() {
+            if path.ends_with(this_file_path) {
+                start_frame_ix = ix + 1;
+                codebase_root_path = path.ancestors().nth(this_file_path.components().count());
+                break;
+            }
+        }
+
+        // Exclude any subsequent frames inside of rust's panic handling system.
+        while let Some((path, _, _)) = backtrace.get(start_frame_ix) {
+            if path.starts_with("/rustc") {
+                start_frame_ix += 1;
+            } else {
+                break;
+            }
+        }
+
+        // Build two backtraces:
+        // * one for display, which includes symbol names for all frames, and files
+        //   and line numbers for symbols in this codebase
+        // * one for identification and de-duplication, which only includes symbol
+        //   names for symbols in this codebase.
+        let mut display_backtrace = Vec::new();
+        let mut identifying_backtrace = Vec::new();
+        for (path, line, symbol) in &backtrace[start_frame_ix..] {
+            display_backtrace.push(symbol.clone());
+
+            if let Some(codebase_root_path) = &codebase_root_path {
+                if let Ok(suffix) = path.strip_prefix(&codebase_root_path) {
+                    identifying_backtrace.push(symbol.clone());
+
+                    let display_path = suffix.to_string_lossy();
+                    if let Some(line) = line {
+                        display_backtrace.push(format!("    {display_path}:{line}"));
+                    } else {
+                        display_backtrace.push(format!("    {display_path}"));
+                    }
+                }
+            }
+        }
 
         let panic_data = Panic {
             thread: thread.into(),
@@ -416,11 +471,6 @@ fn init_panic_hook(app: &App) {
                 file: location.file().into(),
                 line: location.line(),
             }),
-            backtrace: format!("{:?}", backtrace)
-                .split("\n")
-                .map(|line| line.to_string())
-                .collect(),
-            // modified_backtrace: None,
             release_channel: RELEASE_CHANNEL.dev_name().into(),
             os_name: platform.os_name().into(),
             os_version: platform
@@ -432,6 +482,11 @@ fn init_panic_hook(app: &App) {
                 .duration_since(UNIX_EPOCH)
                 .unwrap()
                 .as_millis(),
+            backtrace: display_backtrace,
+            identifying_backtrace: identifying_backtrace
+                .is_empty()
+                .not()
+                .then_some(identifying_backtrace),
         };
 
         if let Some(panic_data_json) = serde_json::to_string_pretty(&panic_data).log_err() {