zhengruifeng opened a new pull request, #44752:
URL: https://github.com/apache/spark/pull/44752

   ### What changes were proposed in this pull request?
   before https://github.com/apache/spark/pull/44689, `df["*"]` and 
`sf.col("*")` are both convert to `UnresolvedStar`, and then 
`Count(UnresolvedStar)` is converted to `Count(1)` in Analyzer:
   
https://github.com/apache/spark/blob/381f3691bd481abc8f621ca3f282e06db32bea31/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/Analyzer.scala#L1893-L1897
   
   in the fix, we introduced a new node `UnresolvedDataFrameStar` for `df["*"]` 
which will be replaced to `ResolvedStar` later. Unfortunately, it doesn't match 
`Count(UnresolvedStar)` any more.
   So it causes:
   ```
   In [1]: from pyspark.sql import functions as sf
   
   In [2]: df1 = spark.createDataFrame([{"id": 1, "val": "v"}])
   
   In [3]: df1.select(sf.count(df1["*"]))
   Out[3]: DataFrame[count(id, val): bigint]
   ```
   
   which should be
   ```
   In [3]: df1.select(sf.count(df1["*"]))
   Out[3]: DataFrame[count(1): bigint]
   ```
   
   In vanilla Spark, it is up to the `count` function to make such conversion 
`sf.count(df1["*"])` -> `sf.count(sf.lit(1))`, see
   
   
https://github.com/apache/spark/blob/e8dfcd3081abe16b2115bb2944a2b1cb547eca8e/sql/core/src/main/scala/org/apache/spark/sql/functions.scala#L422-L436
   
   So it is a natural way to match this behavior on the client side.
   
   ### Why are the changes needed?
   to keep the behavior
   
   
   ### Does this PR introduce _any_ user-facing change?
   it fix the behavior change introduced in 
https://github.com/apache/spark/pull/44689
   
   
   ### How was this patch tested?
   added ut
   
   
   ### Was this patch authored or co-authored using generative AI tooling?
   no


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