planner: fix assertion failure on LogicalJoin.EqualConditions

[zz-jason]

What problem does this PR solve?

127 func (p *LogicalJoin) columnSubstitute(schema *expression.Schema, exprs []expression.Expression) {
128     for i := len(p.EqualConditions) - 1; i >= 0; i-- {
129         p.EqualConditions[i] = expression.ColumnSubstitute(p.EqualConditions[i], schema, exprs).(*expression.ScalarFunction)
130         // After the column substitute, the equal condition may become single side condition.
131         if p.children[0].Schema().Contains(p.EqualConditions[i].GetArgs()[1].(*expression.Column)) {
132             p.LeftConditions = append(p.LeftConditions, p.EqualConditions[i])
133             p.EqualConditions = append(p.EqualConditions[:i], p.EqualConditions[i+1:]...)
134         } else if p.children[1].Schema().Contains(p.EqualConditions[i].GetArgs()[0].(*expression.Column)) {
135             p.RightConditions = append(p.RightConditions, p.EqualConditions[i])
136             p.EqualConditions = append(p.EqualConditions[:i], p.EqualConditions[i+1:]...)
137         }
138     }

At line 131, we assume that the left and right parameter of = is a column after expression.ColumnSubstitute(), which is incorrect.

What is changed and how it works?

Remove that assumption, add a new function expression.CoveredBySchema() to check whether all the columns used by an expression come from that schema.

Check List

Tests

• Unit test
• Integration test

Code changes

• Has exported function/method change

Related changes

• Need to cherry-pick to the release branch

[zz-jason]

/run-all-tests

[zz-jason]

/run-unit-test

[eurekaka]

LGTM

[codecov-io]

Codecov Report

Merging #9066 into master will increase coverage by 0.01%.
The diff coverage is 51.61%.

@@            Coverage Diff             @@
##           master    #9066      +/-   ##
==========================================
+ Coverage   67.26%   67.28%   +0.01%     
==========================================
  Files         371      371              
  Lines       77138    77156      +18     
==========================================
+ Hits        51889    51914      +25     
+ Misses      20617    20614       -3     
+ Partials     4632     4628       -4

Impacted Files	Coverage Δ
planner/core/logical_plans.go	72.24% <30%> (-1.49%)	⬇️
expression/schema.go	94.53% <90.9%> (-0.43%)	⬇️
executor/distsql.go	72.53% <0%> (-0.47%)	⬇️
store/tikv/lock_resolver.go	42.65% <0%> (+0.94%)	⬆️
executor/join.go	78.9% <0%> (+1.04%)	⬆️
infoschema/infoschema.go	77.63% <0%> (+1.31%)	⬆️
store/tikv/2pc.go	81.54% <0%> (+1.82%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update af99a0d...5d89b75. Read the comment docs.

[alivxxx]

LGTM