fix(pii): Don't redact already redacted text [INGEST-109]

CHANGELOG.md

@@ -14,6 +14,7 @@
 **Bug Fixes**:
 
 - Fix regression in CSP report parsing. ([#1174](https://github.com/getsentry/relay/pull/1174))
+- Don't redact already redacted text. ([#1177](https://github.com/getsentry/relay/pull/1177))
 
 ## 22.1.0
 

relay-general/src/pii/processor.rs

@@ -240,13 +240,22 @@ fn apply_regex_to_chunks<'a>(
     // on the chunks, but the `regex` crate does not support that.
 
     let mut search_string = String::new();
+    let mut text_present = false;
     for chunk in &chunks {
         match chunk {
-            Chunk::Text { text } => search_string.push_str(&text.replace("\x00", "")),
+            Chunk::Text { text } => {
+                search_string.push_str(&text.replace("\x00", ""));
+                text_present = true;
+            }
             Chunk::Redaction { .. } => search_string.push('\x00'),
         }
     }
 
+    // Early exit if there isn't any text to be redacted
+    if !text_present {
+        return chunks;
+    }
+
     // Early exit if this regex does not match and return the original chunks.
     let mut captures_iter = regex.captures_iter(&search_string).peekable();
     if captures_iter.peek().is_none() {
@@ -356,7 +365,7 @@ fn insert_replacement_chunks(rule: &RuleRef, text: &str, output: &mut Vec<Chunk<
 
 #[cfg(test)]
 use {
-    crate::pii::PiiConfig,
+    crate::pii::{PiiConfig, ReplaceRedaction},
     crate::processor::process_value,
     crate::protocol::{
         Addr, DebugImage, DebugMeta, Event, ExtraValue, Headers, LogEntry, NativeDebugImage,
@@ -945,3 +954,27 @@ fn test_ip_address_hashing_does_not_overwrite_id() {
 
     assert_eq!(user.id.value().unwrap().as_str(), "123");
 }
+
+#[test]
+fn test_replace_replaced_text() {
+    let chunks = vec![Chunk::Redaction {
+        text: "[Filtered]".into(),
+        rule_id: "@password:filter".into(),
+        ty: RemarkType::Substituted,
+    }];
+    let rule = RuleRef {
+        id: String::from("@password:filter"),
+        origin: String::from("@password:filter"),
+        ty: RuleType::Password,
+        redaction: Redaction::Replace(ReplaceRedaction {
+            text: String::from("[Filtered]"),
+        }),
+    };
+    let res = apply_regex_to_chunks(
+        chunks.clone(),
+        &rule,
+        &Regex::new(r#".*"#).unwrap(),
+        ReplaceBehavior::Value,
+    );
+    assert_eq!(chunks, res);
+}