alamb opened a new issue, #17508:
URL: https://github.com/apache/datafusion/issues/17508

   the following PR adds uuids to certain substrait identifiers to disambiguate 
them, but this may make the plans non reproducable. @Blizzara has some ideas 
how how we can avoid the UUIDs
   - https://github.com/apache/datafusion/pull/17299
   
   
   FWIW, I looked a bit at what it'd take to fix the tracker. I think a core of 
the issue is that DF checks name ambiguity in two ways: there's the 
AmbiguousColumn exception you're running into, and then there is a 
`validate_unique_names()` function which gets called on the creation of the 
Project. The former needs unique non-qualified names, while the latter needs 
unique schema names (which _can_ be qualified). 
   
   An easy fix for the former would be to change `name_for_alias()` into 
`qualified_name()._1` here 
https://github.com/apache/datafusion/blob/1d9e13845021c2e82a012c2e83938c2a7661f295/datafusion/substrait/src/logical_plan/consumer/utils.rs#L398.
 However, that then regresses the latter check (including in the test case for 
this PR), since there will then be a project node with an expr `CAST(B.C as 
Utf8)` with a qualified name ([no qualifier], "B.C") and a schema name "B.C", 
as well as a reference to the original column `B.C` with a qualified name ("B", 
"C") and also schema name "B.C". As the qualified name's name parts are 
different, it wouldn't be renamed (after the change I propose), and then it'd 
fail the `validate_unique_names()` check. So maybe for a proper fix, 
NameTracker would need to track **both the schema name and the name-part of the 
qualified name**, and rename until both are unique.
   
   (A simple example of the behavior of the CAST and validate_unique_names() is 
that `SELECT data.a, CAST(data.a as string) from data;` also fails in 
datafusion-cli.)
   
   _Originally posted by @Blizzara in 
https://github.com/apache/datafusion/pull/17299#discussion_r2330926518_
               


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