gner56 opened a new pull request, #70511:
URL: https://github.com/apache/doris/pull/70511

   …runing
   
   `PluginDrivenScanNode.buildRemainingFilter` decides which conjuncts a 
connector receives for scan planning. The neutral converter, 
`ExprToConnectorExpressionConverter`, unwraps every `CastExpr`, so a connector 
that returns `true` from `supportsCastPredicatePushdown` sees `CAST(col AS T) 
<op> literal` as `col <op> literal`. Iceberg returns `true` and hands the 
result to `TableScan.filter`, which prunes manifests and data files at the 
source.
   
   Issue Number: close #70503
   Related PR: #67933 (the same row loss fixed in the Paimon converter on 
branch-4.x), #55804 (same CAST stripping, string column cast to datetime; not 
fixed by this PR)
   PR Type: Bugfix
   
   Problem Summary:
   
   A predicate comparing an integer column as a string, such as `CAST(id AS 
VARCHAR) >= '100'`, silently returns too few rows on Iceberg tables. The CAST 
is stripped and the string literal is bound to the column's type, so Iceberg 
prunes on `id >= 100`; string and numeric order disagree (`'15' >= '100'`, but 
`15 < 100`), so a data file holding only `15` is skipped and its rows are never 
read. This keeps any conjunct that casts a non-string column to a string type 
in Doris, next to the existing `containsTimestampTzCast` check, so Iceberg and 
every other connector accepting CASTs no longer prune on it. Results become 
correct; such predicates no longer prune files.
   
   - **Frequency:** Every query on an Iceberg table that compares a non-string 
column cast to a string with a range or inequality, when the table's files are 
laid out so the numeric bound excludes a whole file (common once files are 
compacted or sorted by that column). No error is raised.
   - **Root cause:** `ExprToConnectorExpressionConverter.convert` returns 
`convert(expr.getChild(0))` for every `CastExpr`, and 
`IcebergPredicateConverter.extractIcebergLiteral` parses the string literal 
into the column's type (`Integer.parseInt` for INTEGER). Doris still evaluates 
the original predicate on the rows it reads, so only rows in pruned files are 
lost. The `supportsCastPredicatePushdown` javadoc in `IcebergConnectorMetadata` 
names this risk as accepted, with no defect observed.
   - **Why existing tests missed it:** `PluginDrivenScanNodeCastPredicateTest` 
covers only a connector that rejects CASTs (Paimon); with CASTs accepted it 
asserts the conjunct is pushed. No Iceberg suite casts an integer column to a 
string with values split across files.
   - **Fix:** `containsColumnCastToString` matches a `CastExpr` to a string 
type whose child is a non-string `SlotRef`; `buildRemainingFilter` keeps such 
conjuncts local for every connector. A cast of a constant (e.g. `varchar_col > 
date '2023-03-07'`, where Nereids casts the date literal) still compares in 
string order on both sides and keeps being pushed, as 
`test_iceberg_predicate_conversion` q01 expects. Casts to non-string types keep 
being pushed as before.
   - **Other paths and branches:** `buildFilterConstraint` / `applyFilter` is 
not gated; Iceberg does not prune from it, so it is left as is. branch-4.1 and 
branch-4.2 have the same bug in `IcebergUtils.convertDorisExprToSlotRef`, which 
unwraps any `CastExpr` around a `SlotRef`; they need a separate backport.
   
   - Reproduced the bug manually on Doris 4.1.0 with a local Iceberg (hadoop) 
catalog: two INSERTs (`15`, `150`) and `CAST(id AS VARCHAR) >= '100' AND 
CAST(id AS VARCHAR) < '200'` return only `150`, with `icebergPredicatePushdown` 
showing `ref(name="id") >= 100` and one of two splits scanned.
   - Added `columnCastToStringStaysInDorisWhenTheConnectorAcceptsCasts` and 
`otherCastsArePushedWhenTheConnectorAcceptsCasts` to 
`PluginDrivenScanNodeCastPredicateTest`, and the regression suite 
`test_iceberg_cast_to_string_predicate`.
   - Not run locally: the FE build, the unit tests and the regression suite. 
The suite's `.out` file is not included, since it must be generated by running 
the suite; it needs `run external` in CI.
   
   - Two unit cases depend on Nereids keeping the CAST as a `CastExpr`: 
`cast(id as varchar) >= '15' or id = 1` (asserted as a precondition) and 
`cast(id as bigint) > 5` (passes either way). If Nereids rewrites the first, it 
needs a different shape.
   - Matching only casts of a column, not of constants, is deliberate; see Fix 
above.
   
   Fix Iceberg queries that compare a non-string column cast to a string (e.g. 
`CAST(int_col AS VARCHAR) >= '100'`) silently returning too few rows.
   
   - Behavior changed: No
   - Does this need documentation: No
   - Pre-submission status: Partially verified: the fix and tests are not built 
or run locally; the bug was reproduced manually on 4.1.0.
   
   - Tool: Claude Code (Claude)
   - Generated: the code change, the unit and regression tests, and this 
description
   - Human review: EDIT-ME
   
   ### Background
   
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plain sentences, for a reviewer who doesn't know it. Link the user doc if there 
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   ### What problem does this PR solve?
   
   <!-- Issue Number: "close #N" if this PR resolves the issue, "#N" if it only 
relates to it, "None" if there is none. A Feature needs an issue. -->
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such as "#123 (introduced the bug)", separated by commas. Write "None" if no 
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Build/CI/Chore, Revert, Release/Dependency, or Other. -->
   
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   Problem Summary:
   
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   ### Details
   
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answer", in this order:
     Bugfix: Frequency, Root cause, Why existing tests missed it, Fix, Other 
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     Performance: Why it was slow, Optimization, Results, Applicability and cost
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Performance impact, Rollback
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   ### Testing
   
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   ### Notes for Reviewers
   
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   ### Release note
   
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   ### Check List (For Author)
   
   <!-- Behavior changed: "No", or "Yes (see Details)" with a Behavior change 
field in Details. -->
   <!-- Does this need documentation: "No", or "Yes" with the 
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verified; or "Not ready: " and why, for a Draft PR. -->
   
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   ### AI Disclosure
   
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