Gorm offset and limit working unexpectedly, resulting limit 0 in compiled SQL

Environment

golang version: 1.18
gorm version: v1.24.3

Problem

We've been using gorm in our production environment. Recently, I noticed a bad case when setting limit(0). - Prior to v1.24.0: gorm ignores limit 0 - Since v1.24.0: gorm adds limit 0 to the compiled SQL if we set the query condition to db.Offset(0).Limit(0)

Below are some cases I use to explain to problem.

package main

import (
    "fmt"
    "sync"

    "gorm.io/gorm"
    "gorm.io/gorm/clause"
    "gorm.io/gorm/schema"
    "gorm.io/gorm/utils/tests"
)

var db, _ = gorm.Open(tests.DummyDialector{}, nil)

type User struct {
    ID  int `gorm:"column:id" json:"id"`
    Age int `gorm:"column:age" json:"age"`
}

func main() {
    db.DryRun = true
    user, _ := schema.Parse(&User{}, &sync.Map{}, db.NamingStrategy)
    stmt := gorm.Statement{DB: db, Table: user.Table, Schema: user, Clauses: map[string]clause.Clause{}}
    db.Statement = &stmt
    s1 := db.Where("id=?", 1).Offset(0).Limit(0).Find(&User{})
    fmt.Printf("sql is %+v\n", s1.Statement.SQL.String())
    s2 := db.Where("id=?", 1).Limit(0).Offset(0).Find(&User{})
    fmt.Printf("sql is %+v\n", s2.Statement.SQL.String())
        s3 := db.Where("id=?", 1).Limit(0).Find(&User{})
    fmt.Printf("sql is %+v\n", s3.Statement.SQL.String())
}

s1 ouputs: sql is SELECT * FROM `users` WHERE id=? LIMIT 0
s2 outputs: sql is SELECT * FROM `users` WHERE id=?
s3 outputs: sql is SELECT * FROM `users` WHERE id=? LIMIT 0

Which change caused the problem

This commit changed the behavior in clause/limit.go, resulting in the problem.

Possible solution

Since I'm not familiar with the design priciples of gorm, I decide to report an issue instead of submitting a pull request.

I believe the expected behavior of offset and limit would be: - no condition: no extra clauses - limit(0): no extra clauses - offset(0): offset 0 or no extra clauses - limit(a): limit a - offset(b): offset b - limit(0).offset(0): offset 0 or no extra clauses - limit(a).offset(0): offset 0 limit a or limit a - limit(0).offset(b): offset b - limit(a).offset(b): offset b limit a

To conclude: - set limit when limit is not zero - set offset when offset is not zero

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Comment From: Hanwn

Yes, case mentioned by this issue (https://github.com/go-gorm/gorm/issues/5735#issue-1395194394 ) is :

Specifying a limit of 0 results in all rows being returned instead of none

When I execute Limit(0) firstly, then Offset(0) , it will result in sql generted without limit and offset suffix, which means all data satified condition will be returned.

I can try to make a pr to fix it.

Comment From: github-actions[bot]

Comment From: darrenqc

commit

Comment From: darrenqc

commit

Comment From: darrenqc

Yes, case mentioned by this issue (#5735 (comment) ) is :

Specifying a limit of 0 results in all rows being returned instead of none

When I execute Limit(0) firstly, then Offset(0) , it will result in sql generted without limit and offset suffix, which means all data satified condition will be returned.

I can try to make a pr to fix it.

Thanks for attaching the related issue. Do you mean that you will try to solve the difference between Limit(0).Offset(0) and Offset(0).Limit(0) but the behavior for zero values would remain what it is now?

Comment From: github-actions[bot]