Limit the max size of logged eqwalizer errors

Summary:
When people turn on debug logging, it can generate strings that are too long for VS Code to handle, > 512MB.

These typically originate from eqwalizer, when it returns a problem.

Add function to limit a string length for logging, and apply it to possible origins in Eqwalizer ELP code.

There are two variants of the limiting function, one takes a max length, the other uses a constant value.

Reviewed By: VLanvin

Differential Revision: D69311050

fbshipit-source-id: 53188669f2096f25a5e5809a7e49cdc807cdc96f

crates/base_db/src/lib.rs

@@ -509,3 +509,20 @@ pub fn to_quoted_string(input: &str) -> Cow<str> {
         Cow::Owned(format!("'{}'", &input))
     }
 }
+
+// ---------------------------------------------------------------------
+
+// We make the limit fairly generous, we hit problems on the other
+// side with javascript strings > 512 Mb.
+pub const MAX_LOGGED_STRING_LEN: usize = 100_000;
+pub fn truncate_string(s: &str, n: usize) -> String {
+    let chars: Vec<char> = s.chars().collect();
+    if chars.len() > n {
+        format!("{}...", chars.iter().take(n).collect::<String>())
+    } else {
+        s.to_string()
+    }
+}
+pub fn limit_logged_string(s: &str) -> String {
+    truncate_string(s, MAX_LOGGED_STRING_LEN)
+}

crates/eqwalizer/src/ipc.rs

@@ -21,6 +21,7 @@ use std::time::Duration;
 use anyhow::bail;
 use anyhow::Context;
 use anyhow::Result;
+use elp_base_db::limit_logged_string;
 use elp_types_db::eqwalizer::types::Type;
 use elp_types_db::eqwalizer::EqwalizerDiagnostic;
 use fxhash::FxHashMap;
@@ -99,7 +100,7 @@ impl IpcHandle {
                     err, command_str, cmd, &attr
                 );
                 // Show up in error log
-                log::error!("{error_str}");
+                log::error!("{}", limit_logged_string(&error_str));
                 // And show up as an eqwalizer error
                 bail!(error_str);
             }

crates/eqwalizer/src/lib.rs

@@ -21,6 +21,7 @@ use anyhow::Context;
 use anyhow::Result;
 use ast::Error;
 use ast::Pos;
+use elp_base_db::limit_logged_string;
 use elp_base_db::ModuleName;
 use elp_base_db::ProjectId;
 use elp_types_db::eqwalizer::types::Type;
@@ -327,8 +328,8 @@ fn do_typecheck(
             }
             msg => {
                 log::warn!(
-                    "received unexpected message from eqwalizer, ignoring: {:?}",
-                    msg
+                    "received unexpected message from eqwalizer, ignoring: {}",
+                    limit_logged_string(&format!("{:?}", msg))
                 )
             }
         }
@@ -464,8 +465,8 @@ fn get_module_diagnostics(
             }
             msg => {
                 log::warn!(
-                    "received unexpected message from eqwalizer, ignoring: {:?}",
-                    msg
+                    "received unexpected message from eqwalizer, ignoring: {}",
+                    limit_logged_string(&format!("{:?}", msg))
                 )
             }
         }

crates/ide_db/src/lib.rs

@@ -13,6 +13,7 @@ use std::panic::RefUnwindSafe;
 use std::path::PathBuf;
 use std::sync::Arc;
 
+use elp_base_db::limit_logged_string;
 use elp_base_db::salsa;
 use elp_base_db::AbsPathBuf;
 use elp_base_db::FileId;
@@ -398,7 +399,11 @@ impl TypedSemantic for RootDatabase {
             ),
             EqwalizerDiagnostics::NoAst { .. } => Some(vec![]),
             EqwalizerDiagnostics::Error(err) => {
-                log::error!("EqWAlizer failed for {}: {}", module.as_str(), err);
+                log::error!(
+                    "EqWAlizer failed for {}: {}",
+                    module.as_str(),
+                    limit_logged_string(err)
+                );
                 Some(vec![])
             }
         }