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LogStorage: fix log limits (lines/length/size) with multi-line log msgs #134

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Merged
syphar merged 1 commit into from
May 22, 2026
+86 −32
Merged

LogStorage: fix log limits (lines/length/size) with multi-line log msgs #134

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118 changes: 86 additions & 32 deletions src/logging.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -174,43 +174,45 @@ impl SealedLog for LogStorage {
if inner.truncated {
return;
}
if let Some(max_lines) = self.max_lines
&& inner.records.len() >= max_lines
{
inner.records.push(StoredRecord {
level: Level::Warn,
message: "too many lines in the log, truncating it".into(),
});
inner.truncated = true;
return;
}
let mut message = record.args().to_string();

if let Some(max_line_length) = self.max_line_length
&& message.len() > max_line_length
{
let mut length = max_line_length - 3;
while !message.is_char_boundary(length) {
length -= 1;

for mut message in record.args().to_string().lines().map(ToOwned::to_owned) {
if let Some(max_lines) = self.max_lines
&& inner.records.len() >= max_lines
{
inner.records.push(StoredRecord {
level: Level::Warn,
message: "too many lines in the log, truncating it".into(),
});
inner.truncated = true;
return;
}
message = format!("{}...", &message[..length]);
}

if let Some(max_size) = self.max_size
&& inner.size + message.len() >= max_size
{
if let Some(max_line_length) = self.max_line_length
&& message.len() > max_line_length
{
let mut length = max_line_length - 3;
while !message.is_char_boundary(length) {
length -= 1;
}
Comment on lines +193 to +196
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@Skgland Skgland May 21, 2026 •
edited
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Suggested change
let mut length = max_line_length - 3;
while !message.is_char_boundary(length) {
length -= 1;
}
let length = message.floor_char_boundary(max_line_length - 3);

Could this use str::floor_char_boundary or is this newer than rustwides msrv?

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@syphar syphar May 21, 2026

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we currently have 1.89 in there, that method case with 1.91.

I feel like this is not reason enough to push the msrv?

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@Skgland Skgland May 21, 2026

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Ok, sounds reasonable to not bump the msrv for just this.

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@syphar syphar May 21, 2026

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I'm also always wondering how many real-world users outside of the rust org actually exist, so if the msrv la really important to them

message = format!("{}...", &message[..length]);
}

if let Some(max_size) = self.max_size
&& inner.size + message.len() >= max_size
{
inner.records.push(StoredRecord {
level: Level::Warn,
message: "too much data in the log, truncating it".into(),
});
inner.truncated = true;
return;
}
inner.size += message.len();
inner.records.push(StoredRecord {
level: Level::Warn,
message: "too much data in the log, truncating it".into(),
level: record.level(),
message,
});
inner.truncated = true;
return;
}
inner.size += message.len();
inner.records.push(StoredRecord {
level: record.level(),
message,
});
}

fn flush(&self) {}
Expand Down Expand Up @@ -376,6 +378,58 @@ mod tests {
);
}

#[test]
fn test_multiline_messages_are_split_into_records() {
logging::init();

let storage = LogStorage::new(LevelFilter::Info);
logging::capture(&storage, || {
info!("first\nsecond\nthird");
});

assert_eq!(
storage.inner.lock().unwrap().records,
vec![
StoredRecord {
level: Level::Info,
message: "first".to_string(),
},
StoredRecord {
level: Level::Info,
message: "second".to_string(),
},
StoredRecord {
level: Level::Info,
message: "third".to_string(),
},
]
);
}

#[test]
fn test_multiline_messages_respect_max_lines() {
logging::init();

let mut storage = LogStorage::new(LevelFilter::Info);
storage.set_max_lines(2);
logging::capture(&storage, || {
info!("first\nsecond\nthird");
});

let inner = storage.inner.lock().unwrap();
assert_eq!(inner.records.len(), 3);
assert_eq!(inner.records[0].message, "first");
assert_eq!(inner.records[1].message, "second");
assert!(
inner
.records
.last()
.unwrap()
.message
.contains("too many lines")
);
}

#[test]
fn test_too_long_line() {
logging::init();
Expand Down
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