Hello Quanlong Huang, Daniel Becker, Joe McDonnell, Csaba Ringhofer, Impala 
Public Jenkins,

I'd like you to reexamine a change. Please visit

    http://gerrit.cloudera.org:8080/20425

to look at the new patch set (#4).

Change subject: IMPALA-10086: Implicit cast comparing char and varchar
......................................................................

IMPALA-10086: Implicit cast comparing char and varchar

Until IMPALA-7368, Impala allowed comparing char and varchar slots as in

  select * from functional.chars_tiny where cs = vc;

IMPALA-7368 added DATE type support, and as part of that changed
function call resolution to use a fit function based on the number of
arguments that match the call types. Previously the comparison above
would take the first matching function, which happened to be equality
between STRING and STRING; CHAR and VARCHAR can both be implicitly cast
to STRING, so this function worked. With the new function resolution,
the best fit is equality between VARCHAR and VARCHAR, however implicit
casting to VARCHAR(*) from CHAR wasn't allowed.

The behavior before IMPALA-7368 was somewhat accidental; it depended on
the order that builtin EQ functions are added via
BinaryPredicate.initBuiltins -> Type.getSupportedTypes. Supported types
happened to be ordered with STRING preceding VARCHAR and CHAR. The fit
function makes sense and changing its behavior may have other
consequences; it also makes sense that CHAR should be castable to
VARCHAR.

This change allows implicit cast between matching types. That includes
equals, and adds casting to a compatible type when it is a char or
varchar and the target type is a wildcard version of the same.

Adds tests covering cast comparison and other implicit conversions.

Does not attempt to address differences from CHAR padding (IMPALA-1652).

Change-Id: Ib89d0a391bc8f2152ecd9151c8872a01ba19c436
---
M fe/src/main/java/org/apache/impala/analysis/Expr.java
M fe/src/test/java/org/apache/impala/analysis/AnalyzeExprsTest.java
M tests/query_test/test_cast_with_format.py
3 files changed, 72 insertions(+), 9 deletions(-)


  git pull ssh://gerrit.cloudera.org:29418/Impala-ASF refs/changes/25/20425/4
--
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Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-MessageType: newpatchset
Gerrit-Change-Id: Ib89d0a391bc8f2152ecd9151c8872a01ba19c436
Gerrit-Change-Number: 20425
Gerrit-PatchSet: 4
Gerrit-Owner: Michael Smith <michael.sm...@cloudera.com>
Gerrit-Reviewer: Csaba Ringhofer <csringho...@cloudera.com>
Gerrit-Reviewer: Daniel Becker <daniel.bec...@cloudera.com>
Gerrit-Reviewer: Impala Public Jenkins <impala-public-jenk...@cloudera.com>
Gerrit-Reviewer: Joe McDonnell <joemcdonn...@cloudera.com>
Gerrit-Reviewer: Michael Smith <michael.sm...@cloudera.com>
Gerrit-Reviewer: Quanlong Huang <huangquanl...@gmail.com>

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