Baymine opened a new pull request, #57472:
URL: https://github.com/apache/doris/pull/57472
### What problem does this PR solve?
Doris fails to read Parquet files containing empty arrays (e.g., `[]` or
`["{[]}"]`) with the following error:
Wrong data type for column 'array', expected Struct type, actual type id 15
Issue Number: close #xxx
Related PR: #xxx
Problem Summary:
The `is_struct_list_node()` function in `schema_desc.cpp` uses name-based
heuristics to distinguish between:
1. Simple list elements (e.g., `array<int>`)
2. List of struct elements (e.g., `array<struct<...>>`)
However, it fails to check whether a schema node has a **physical type**
before applying these heuristics.
In standard Parquet 3-level list encoding:
```
optional group column (LIST) {
repeated group array {
optional binary element (STRING);
}
```
The middle "array" node is just a **structural container** without a
physical type (`schema.__isset.type = false`). The current code incorrectly
treats this container as a struct type because of its name, leading to:
1. Parser takes wrong branch (treats as list-of-struct instead of simple
list)
2. Creates `StructColumnReader` instead of `ArrayColumnReader`
3. Runtime type mismatch: expects `TypeIndex::Struct`, gets
`TypeIndex::Array`
### Release note
None
### Check List (For Author)
- Test <!-- At least one of them must be included. -->
- [ ] Regression test
- [ ] Unit Test
- [ ] Manual test (add detailed scripts or steps below)
- [ ] No need to test or manual test. Explain why:
- [ ] This is a refactor/code format and no logic has been changed.
- [ ] Previous test can cover this change.
- [ ] No code files have been changed.
- [ ] Other reason <!-- Add your reason? -->
- Behavior changed:
- [ ] No.
- [ ] Yes. <!-- Explain the behavior change -->
- Does this need documentation?
- [ ] No.
- [ ] Yes. <!-- Add document PR link here. eg:
https://github.com/apache/doris-website/pull/1214 -->
### Check List (For Reviewer who merge this PR)
- [ ] Confirm the release note
- [ ] Confirm test cases
- [ ] Confirm document
- [ ] Add branch pick label <!-- Add branch pick label that this PR should
merge into -->
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