fix: AfterQuery using safer right trim to clear FROM clause's joins #7150
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added 2 commits
August 9, 2024 16:48
| @@ -288,7 +288,7 @@ func AfterQuery(db *gorm.DB) { | |||
| // clear the joins after query because preload need it | |||
| if v, ok := db.Statement.Clauses["FROM"].Expression.(clause.From); ok { | |||
| fromClause := db.Statement.Clauses["FROM"] | |||
| fromClause.Expression = clause.From{Tables: v.Tables, Joins: v.Joins[:len(v.Joins)-len(db.Statement.Joins)]} // keep the original From Joins | |||
| fromClause.Expression = clause.From{Tables: v.Tables, Joins: utils.RTrimSlice(v.Joins, len(v.Joins)-len(db.Statement.Joins))} // keep the original From Joins | |||
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utils.RTrimSlice makes sure no panic when v.Joins is empty while db.Statement.Joins is not
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As a fix to this issue , clearing of db.Statement.Clauses["FROM"] was in introduced in this pull-request
At https://github.com/go-gorm/gorm/blob/master/callbacks/query.go#L291 , it can cause a panic if
db.Statement.Clauses["FROM"].Joinsslice is being sliced using negative upper bound index. Please observe below the case reproduced in current source codeIn the case above, wrong column name
pets.names(instead of pets.name) is passed as query.When
Count()is called afterFind()on the the samegorm.DBinstance with a wrong query, it calls AfterQuery twice which in turn tries to trim the slice twice which now is empty after first trim. Hence instead of obtaining actual SQL error, it causes a panic due to index out of bound error.What did this pull request do?
This Pull Request:
db.Statement.Clauses["FROM"].JoinsUser Case Description
User Case:
In one of my our projects, we are using gorm (just fantastic) as ORM support for Postgres. After upgrading gorm version from
v1.9.16->v1.25.11, we identified panic in API due to broken migration which changes a column name causing the query to be wrong.Of course this is a minor fix requirement but much needed to prevent API server error and handle SQL error gracefully.