cmd/go: `go mod tidy -diff` will sometimes complain about things `go mod tidy` silently ignores

[doismellburning]

Go version

go version go1.25.1 linux/amd64

Output of go env in your module/workspace:

AR='ar'
CC='gcc'
CGO_CFLAGS='-O2 -g'
CGO_CPPFLAGS=''
CGO_CXXFLAGS='-O2 -g'
CGO_ENABLED='1'
CGO_FFLAGS='-O2 -g'
CGO_LDFLAGS='-O2 -g'
CXX='g++'
GCCGO='gccgo'
GO111MODULE=''
GOAMD64='v1'
GOARCH='amd64'
GOAUTH='netrc'
GOBIN=''
GOCACHE='/home/maior/.cache/go-build'
GOCACHEPROG=''
GODEBUG=''
GOENV='/home/maior/.config/go/env'
GOEXE=''
GOEXPERIMENT=''
GOFIPS140='off'
GOFLAGS=''
GOGCCFLAGS='-fPIC -m64 -pthread -Wl,--no-gc-sections -fmessage-length=0 -ffile-prefix-map=/tmp/go-build603266283=/tmp/go-build -gno-record-gcc-switches'
GOHOSTARCH='amd64'
GOHOSTOS='linux'
GOINSECURE=''
GOMOD='/home/maior/git/samoyed/go.mod'
GOMODCACHE='/home/maior/go/pkg/mod'
GONOPROXY=''
GONOSUMDB=''
GOOS='linux'
GOPATH='/home/maior/go'
GOPRIVATE=''
GOPROXY='https://proxy.golang.org,direct'
GOROOT='/home/maior/go-1.25'
GOSUMDB='sum.golang.org'
GOTELEMETRY='local'
GOTELEMETRYDIR='/home/maior/.config/go/telemetry'
GOTMPDIR=''
GOTOOLCHAIN='auto'
GOTOOLDIR='/home/maior/go-1.25/pkg/tool/linux_amd64'
GOVCS=''
GOVERSION='go1.25.1'
GOWORK=''
PKG_CONFIG='pkg-config'

What did you do?

I have a go.sum file where go mod tidy makes no changes and exits successfully without complaint, but go mod tidy -diff fails with a proposed reordering change. I believe these two should be consistent - if go mod tidy succeeds, go mod tidy -diff should succeed, and vice versa.

I am still trying to construct a minimal example, but I encountered this with https://github.com/doismellburning/samoyed/blob/3cf27a5666a703386fa6ae36347165589a8c0753/go.mod and https://github.com/doismellburning/samoyed/blob/3cf27a5666a703386fa6ae36347165589a8c0753/go.sum per below:

$ cat go.mod
module github.com/doismellburning/samoyed

go 1.25

require (
        github.com/brutella/dnssd v1.2.14
        github.com/creack/pty v1.1.24
        github.com/golang/geo v0.0.0-20180826223333-635502111454
        github.com/jochenvg/go-udev v0.0.0-20240801134859-b65ed646224b
        github.com/lestrrat-go/strftime v1.1.1
        github.com/pkg/term v1.1.0
        github.com/spf13/pflag v1.0.10
        github.com/stretchr/testify v1.11.1
        github.com/tzneal/coordconv v0.1.2
        github.com/warthog618/go-gpiocdev v0.9.1
        github.com/xylo04/goHamlib v0.0.0-20240309005711-30dd4ae13b38
        golang.org/x/sys v0.31.0
        gopkg.in/yaml.v3 v3.0.1
        pgregory.net/rapid v1.2.0
)

require (
        github.com/davecgh/go-spew v1.1.1 // indirect
        github.com/jkeiser/iter v0.0.0-20200628201005-c8aa0ae784d1 // indirect
        github.com/miekg/dns v1.1.61 // indirect
        github.com/pmezard/go-difflib v1.0.0 // indirect
        github.com/vishvananda/netlink v1.2.1-beta.2 // indirect
        github.com/vishvananda/netns v0.0.0-20200728191858-db3c7e526aae // indirect
        golang.org/x/mod v0.18.0 // indirect
        golang.org/x/net v0.38.0 // indirect
        golang.org/x/sync v0.7.0 // indirect
        golang.org/x/tools v0.22.0 // indirect
)

$ cat go.sum
github.com/brutella/dnssd v1.2.14 h1:qLpTnRTm5peo2jA30hqMIbCuWn8x3sFg3e9o9ODOobw=
github.com/brutella/dnssd v1.2.14/go.mod h1:tG4GE8orv6+irE5rdsNgb6MJSxm6cyMUKdC5jmD22gk=
github.com/creack/pty v1.1.24 h1:bJrF4RRfyJnbTJqzRLHzcGaZK1NeM5kTC9jGgovnR1s=
github.com/creack/pty v1.1.24/go.mod h1:08sCNb52WyoAwi2QDyzUCTgcvVFhUzewun7wtTfvcwE=
github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
github.com/golang/geo v0.0.0-20180826223333-635502111454 h1:UiKw4ZsXdOM6qRj2nP54DJY6Mp3Vd+aSu1OhPvPR+94=
github.com/golang/geo v0.0.0-20180826223333-635502111454/go.mod h1:vgWZ7cu0fq0KY3PpEHsocXOWJpRtkcbKemU4IUw0M60=
github.com/jkeiser/iter v0.0.0-20200628201005-c8aa0ae784d1 h1:smvLGU3obGU5kny71BtE/ibR0wIXRUiRFDmSn0Nxz1E=
github.com/jkeiser/iter v0.0.0-20200628201005-c8aa0ae784d1/go.mod h1:fP/NdyhRVOv09PLRbVXrSqHhrfQypdZwgE2L4h2U5C8=
github.com/jochenvg/go-udev v0.0.0-20240801134859-b65ed646224b h1:Pzf7tldbCVqwl3NnOnTamEWdh/rL41fsoYCn2HdHgRA=
github.com/jochenvg/go-udev v0.0.0-20240801134859-b65ed646224b/go.mod h1:IBDUGq30U56w969YNPomhMbRje1GrhUsCh7tHdwgLXA=
github.com/lestrrat-go/envload v0.0.0-20180220234015-a3eb8ddeffcc h1:RKf14vYWi2ttpEmkA4aQ3j4u9dStX2t4M8UM6qqNsG8=
github.com/lestrrat-go/envload v0.0.0-20180220234015-a3eb8ddeffcc/go.mod h1:kopuH9ugFRkIXf3YoqHKyrJ9YfUFsckUU9S7B+XP+is=
github.com/lestrrat-go/strftime v1.1.1 h1:zgf8QCsgj27GlKBy3SU9/8MMgegZ8UCzlCyHYrUF0QU=
github.com/lestrrat-go/strftime v1.1.1/go.mod h1:YDrzHJAODYQ+xxvrn5SG01uFIQAeDTzpxNVppCz7Nmw=
github.com/miekg/dns v1.1.61 h1:nLxbwF3XxhwVSm8g9Dghm9MHPaUZuqhPiGL+675ZmEs=
github.com/miekg/dns v1.1.61/go.mod h1:mnAarhS3nWaW+NVP2wTkYVIZyHNJ098SJZUki3eykwQ=
github.com/pkg/errors v0.9.1 h1:FEBLx1zS214owpjy7qsBeixbURkuhQAwrK5UwLGTwt4=
github.com/pkg/errors v0.9.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
github.com/pkg/term v1.1.0 h1:xIAAdCMh3QIAy+5FrE8Ad8XoDhEU4ufwbaSozViP9kk=
github.com/pkg/term v1.1.0/go.mod h1:E25nymQcrSllhX42Ok8MRm1+hyBdHY0dCeiKZ9jpNGw=
github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
github.com/spf13/pflag v1.0.10 h1:4EBh2KAYBwaONj6b2Ye1GiHfwjqyROoF4RwYO+vPwFk=
github.com/spf13/pflag v1.0.10/go.mod h1:McXfInJRrz4CZXVZOBLb0bTZqETkiAhM9Iw0y3An2Bg=
github.com/stretchr/testify v1.11.1 h1:7s2iGBzp5EwR7/aIZr8ao5+dra3wiQyKjjFuvgVKu7U=
github.com/stretchr/testify v1.11.1/go.mod h1:wZwfW3scLgRK+23gO65QZefKpKQRnfz6sD981Nm4B6U=
github.com/tzneal/coordconv v0.1.2 h1:/NHhypAezdfJDxkkZkvUKG/2j8AREmNwcwcsJ+AjbaI=
github.com/tzneal/coordconv v0.1.2/go.mod h1:Do+bbQ+Atbh2PwYWDwFEIJfTIIFShEzIQBt9oRIdTFc=
github.com/vishvananda/netlink v1.2.1-beta.2 h1:Llsql0lnQEbHj0I1OuKyp8otXp0r3q0mPkuhwHfStVs=
github.com/vishvananda/netlink v1.2.1-beta.2/go.mod h1:twkDnbuQxJYemMlGd4JFIcuhgX83tXhKS2B/PRMpOho=
github.com/vishvananda/netns v0.0.0-20200728191858-db3c7e526aae h1:4hwBBUfQCFe3Cym0ZtKyq7L16eZUtYKs+BaHDN6mAns=
github.com/vishvananda/netns v0.0.0-20200728191858-db3c7e526aae/go.mod h1:DD4vA1DwXk04H54A1oHXtwZmA0grkVMdPxx/VGLCah0=
github.com/warthog618/go-gpiocdev v0.9.1 h1:pwHPaqjJfhCipIQl78V+O3l9OKHivdRDdmgXYbmhuCI=
github.com/warthog618/go-gpiocdev v0.9.1/go.mod h1:dN3e3t/S2aSNC+hgigGE/dBW8jE1ONk9bDSEYfoPyl8=
github.com/warthog618/go-gpiosim v0.1.1 h1:MRAEv+T+itmw+3GeIGpQJBfanUVyg0l3JCTwHtwdre4=
github.com/warthog618/go-gpiosim v0.1.1/go.mod h1:YXsnB+I9jdCMY4YAlMSRrlts25ltjmuIsrnoUrBLdqU=
golang.org/x/mod v0.18.0 h1:5+9lSbEzPSdWkH32vYPBwEpX8KwDbM52Ud9xBUvNlb0=
golang.org/x/mod v0.18.0/go.mod h1:hTbmBsO62+eylJbnUtE2MGJUyE7QWk4xUqPFrRgJ+7c=
golang.org/x/net v0.38.0 h1:vRMAPTMaeGqVhG5QyLJHqNDwecKTomGeqbnfZyKlBI8=
golang.org/x/net v0.38.0/go.mod h1:ivrbrMbzFq5J41QOQh0siUuly180yBYtLp+CKbEaFx8=
golang.org/x/sync v0.7.0 h1:YsImfSBoP9QPYL0xyKJPq0gcaJdG3rInoqxTWbfQu9M=
golang.org/x/sync v0.7.0/go.mod h1:Czt+wKu1gCyEFDUtn0jG5QVvpJ6rzVqr5aXyt9drQfk=
golang.org/x/sys v0.0.0-20200217220822-9197077df867/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
golang.org/x/sys v0.0.0-20200728102440-3e129f6d46b1/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
github.com/xylo04/goHamlib v0.0.0-20240309005711-30dd4ae13b38 h1:i4T4cGNmQzrH8jC4y8aCs02sNdTnN4tIXS6s/2JTDr8=
github.com/xylo04/goHamlib v0.0.0-20240309005711-30dd4ae13b38/go.mod h1:5vG7aLrTt+9T+2ob8W5WHCF4WYBPl70GpYvcGxLgfck=
golang.org/x/sys v0.0.0-20200909081042-eff7692f9009/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
golang.org/x/sys v0.31.0 h1:ioabZlmFYtWhL+TRYpcnNlLwhyxaM9kWTDEmfnprqik=
golang.org/x/sys v0.31.0/go.mod h1:BJP2sWEmIv4KK5OTEluFJCKSidICx8ciO85XgH3Ak8k=
golang.org/x/tools v0.22.0 h1:gqSGLZqv+AI9lIQzniJ0nZDRG5GBPsSi+DRNHWNz6yA=
golang.org/x/tools v0.22.0/go.mod h1:aCwcsjqvq7Yqt6TNyX7QMU2enbQ/Gt0bo6krSeEri+c=
gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
pgregory.net/rapid v1.2.0 h1:keKAYRcjm+e1F0oAuU5F5+YPAWcyxNNRK2wud503Gnk=
pgregory.net/rapid v1.2.0/go.mod h1:PY5XlDGj0+V1FCq0o192FdRhpKHGTRIWBgqjDBTrq04=

$ go mod tidy
$ echo $?
0

$ go mod tidy -diff
diff current/go.sum tidy/go.sum
--- current/go.sum
+++ tidy/go.sum
@@ -36,6 +36,8 @@
 github.com/warthog618/go-gpiocdev v0.9.1/go.mod h1:dN3e3t/S2aSNC+hgigGE/dBW8jE1ONk9bDSEYfoPyl8=
 github.com/warthog618/go-gpiosim v0.1.1 h1:MRAEv+T+itmw+3GeIGpQJBfanUVyg0l3JCTwHtwdre4=
 github.com/warthog618/go-gpiosim v0.1.1/go.mod h1:YXsnB+I9jdCMY4YAlMSRrlts25ltjmuIsrnoUrBLdqU=
+github.com/xylo04/goHamlib v0.0.0-20240309005711-30dd4ae13b38 h1:i4T4cGNmQzrH8jC4y8aCs02sNdTnN4tIXS6s/2JTDr8=
+github.com/xylo04/goHamlib v0.0.0-20240309005711-30dd4ae13b38/go.mod h1:5vG7aLrTt+9T+2ob8W5WHCF4WYBPl70GpYvcGxLgfck=
 golang.org/x/mod v0.18.0 h1:5+9lSbEzPSdWkH32vYPBwEpX8KwDbM52Ud9xBUvNlb0=
 golang.org/x/mod v0.18.0/go.mod h1:hTbmBsO62+eylJbnUtE2MGJUyE7QWk4xUqPFrRgJ+7c=
 golang.org/x/net v0.38.0 h1:vRMAPTMaeGqVhG5QyLJHqNDwecKTomGeqbnfZyKlBI8=
@@ -44,8 +46,6 @@
 golang.org/x/sync v0.7.0/go.mod h1:Czt+wKu1gCyEFDUtn0jG5QVvpJ6rzVqr5aXyt9drQfk=
 golang.org/x/sys v0.0.0-20200217220822-9197077df867/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20200728102440-3e129f6d46b1/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
-github.com/xylo04/goHamlib v0.0.0-20240309005711-30dd4ae13b38 h1:i4T4cGNmQzrH8jC4y8aCs02sNdTnN4tIXS6s/2JTDr8=
-github.com/xylo04/goHamlib v0.0.0-20240309005711-30dd4ae13b38/go.mod h1:5vG7aLrTt+9T+2ob8W5WHCF4WYBPl70GpYvcGxLgfck=
 golang.org/x/sys v0.0.0-20200909081042-eff7692f9009/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.31.0 h1:ioabZlmFYtWhL+TRYpcnNlLwhyxaM9kWTDEmfnprqik=
 golang.org/x/sys v0.31.0/go.mod h1:BJP2sWEmIv4KK5OTEluFJCKSidICx8ciO85XgH3Ak8k=
$ echo $?
1

What did you see happen?

I ran go mod tidy and it exited successfully and made no changes, but go mod tidy -diff complained and generated a reordering diff for go.sum

What did you expect to see?

I believe that if go mod tidy exits successfully with no changes made, go mod tidy -diff should also exit successfully with no complaints

[gabyhelp]

Related Issues

• cmd/go: 'go mod tidy -diff' doesn't accurately indicate the changes that 'go mod tidy' will make #75299
• cmd/go: 'go mod tidy' retains sums for modules in the requirement graph but not the build list #39424 (closed)
• go mod download modifying go.sum after go mod tidy #44512 (closed)
• cmd/go: go mod download and go mod tidy produce different go.sum #35832 (closed)
• x/vuln/cmd/vulncheck: adds entries to `go.sum` #65170 (closed)
• cmd/go: spurious "missing go.sum entry" errors #63914 (closed)
• cmd/go: mod tidy result different from previous go version #47847 (closed)
• cmd/go: mod tidy doesn't remove unused dependencies in go.sum, in same cases #37842 (closed)
• cmd/go: `go mod tidy` and `go mod download` don't agree on same go.sum file. #44441 (closed)
• cmd/go: "mod tidy" on tip can tidy less than 1.17 #49598 (closed)

_{(Emoji vote if this was helpful or unhelpful; more detailed feedback welcome in this discussion.)}

[mrkfrmn]

@golang/command-line

[alain91]

How is it possible to have a go.sum file not sorted ?
At the present time, in the repository github.com/doismellburning/samoyed go.sum file is well sorted. Is the issue still available ?

[doismellburning]

@alain91 In this case, via git merge conflict resolution.

I suspect that there aren't many expected ways that would lead to an unsorted go.sum file (other than e.g. that, and adversarial editing), and that rarity is how this edge-case has slipped through.

If you grab https://github.com/doismellburning/samoyed/ at commit 3cf27a5666a703386fa6ae36347165589a8c0753 (which I've now tagged as golang/go/issues/77713 to avoid any gc etc.) you should be able to reproduce it

[alain91]

After investigation, to fix this issue one must insert a sort of currentGoSum in modload/load.go (near line 471) before to diff with tidyGoSum. This fix works on my PC.

But we could also say that the original behavior is correct because the two files are not exactly in the same order despite the fact that 'go mod tidy' doesn't complain (something like semantics vs syntaxics)

[matloob]

It's incorrect if go mod tidy and go mod tidy "disagree" with each other. If go mod tidy won't change a file, the diff returned by go mod tidy -diff should be empty.

[alain91]

At functional level, the two files shown have the same values for requiments. The order is not so important.

In a previous post, I suggest to add a sort of currentGoSum to fixe this issue and have an 0 exit code value.

[ethanmontgomery148-hub]

That resolved the issue on my end

…

On Mon, Mar 16, 2026, 4:14 PM alain91 ***@***.***> wrote: *alain91* left a comment (golang/go#77713) <#77713 (comment)> At functional level, the two files shown have the same values for requiments. The order is not so important. In a previous post, I suggest to add a sort of currentGoSum to fixe this issue and have an 0 exit code value. — Reply to this email directly, view it on GitHub <#77713 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/B7BKMDXM6KRKSYXTXJQEMCD4RBVB7AVCNFSM6AAAAACV2OLJ6KVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHM2DANZQGYZDSNJYGY> . You are receiving this because you are subscribed to this thread.Message ID: ***@***.***>