spring-projects / spring-projects/spring-ai
Stack overflow exception in trimAdjacentBlankLines() method due to inefficient regex in ExtractedTextFormatter
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Description
Bug description
When using TikaDocumentReader, I often encountered the following error:
java
Caused by: java.lang.StackOverflowError: null
at java.base/java.util.regex.Pattern$Caret.match(Pattern.java:3896)
at java.base/java.util.regex.Pattern$Curly.match1(Pattern.java:4597)
at java.base/java.util.regex.Pattern$Curly.match(Pattern.java:4546)
at java.base/java.util.regex.Pattern$Dollar.match(Pattern.java:3996)
at java.base/java.util.regex.Pattern$Caret.match(Pattern.java:3906)
at java.base/java.util.regex.Pattern$GroupHead.match(Pattern.java:4969).
After debugging, I found that the issue lies in the non-optimized regular expression from the trimAdjacentBlankLines() method in the ExtractedTextFormatter class. In my case, the problem occasionally occurred even with a files with small number of empty lines (~150) with default VM stack settings -Xmx8192m.
Steps to reproduce
For testing the occurrence of this error, I created an XLSX file with a large number of empty rows. I am attaching it to this issue.
Stack_overflow_exception_test.xlsx
Contributor guide
First steps
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Research direction
Start in ExtractedTextFormatter at trimAdjacentBlankLines() and inspect the regular expression used there. Run the attached Stack_overflow_exception_test.xlsx through TikaDocumentReader to reproduce the failure, then verify that formatting completes without StackOverflowError while adjacent blank lines are still trimmed.
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Assessment
- Tech stack
- java
- Domain
- backend, performance
- Issue type
- Bug
- Difficulty
- 2/5
- Estimated time
- 1-3 hours
- Activity status
- Quiet
- Clarity
- Clearly specified
- Newbie friendliness
- 68/100