Getting "file not found" error for external package interfaces with v3 but not v2

[takanuva15]

Description

I'm trying to migrate our mockery config from v2 to v3. Here's my v2 config:

dir: "test/mocks/{{.InterfaceDirRelative}}"
filename: "{{.InterfaceNameSnake}}_mock.go"
mockname: "{{.InterfaceName}}Mock"
include-auto-generated: false
packages:
  mockery3pkggen:
    config:
      all: true
  github.com/stevenferrer/solr-go:
    config:
      all: true
      recursive: true

And here's what mockery3 generated via mockery migrate in .mockery_v3.yml:

dir: test/mocks/{{.InterfaceDirRelative}}
include-auto-generated: false
structname: '{{.InterfaceName}}Mock'
template: testify
template-data:
  unroll-variadic: true
packages:
  github.com/stevenferrer/solr-go:
    config:
      all: true
      recursive: true
  mockery3pkggen:
    config:
      all: true

After running mockery3 --config .mockery_v3.yml, I just get this error:

$ mockery3 --config .mockery_v3.yml 
2026-04-01T17:30:44.482480000-04:00 INF Starting mockery config-file=.mockery_v3.yml version=v3.7.0
2026-04-01T17:30:44.482567000-04:00 INF Parsing configured packages... version=v3.7.0
2026-04-01T17:30:44.793681000-04:00 INF Done parsing configured packages. version=v3.7.0
2026-04-01T17:30:44.794416000-04:00 INF adding interface to collection collection=../go/pkg/mod/github.com/stevenferrer/solr-go@v0.4.0/mocks_test.go interface=Client package-path=github.com/stevenferrer/solr-go version=v3.7.0
2026-04-01T17:30:44.794512000-04:00 INF adding interface to collection collection=../go/pkg/mod/github.com/stevenferrer/solr-go@v0.4.0/mocks_test.go interface=Faceter package-path=github.com/stevenferrer/solr-go version=v3.7.0
2026-04-01T17:30:44.794593000-04:00 INF adding interface to collection collection=../go/pkg/mod/github.com/stevenferrer/solr-go@v0.4.0/mocks_test.go interface=QueryParser package-path=github.com/stevenferrer/solr-go version=v3.7.0
2026-04-01T17:30:44.794673000-04:00 INF adding interface to collection collection=../go/pkg/mod/github.com/stevenferrer/solr-go@v0.4.0/mocks_test.go interface=RequestSender package-path=github.com/stevenferrer/solr-go version=v3.7.0
2026-04-01T17:30:44.795657000-04:00 ERR failed to find output package path error="file not found" file=../go/pkg/mod/github.com/stevenferrer/solr-go@v0.4.0/mocks_test.go out-pkg-name=solr outPkgFSPath=/Users/myuser/Documents/Repositories/go/pkg/mod/github.com/stevenferrer/solr-go@v0.4.0 src-pkg-name=solr srcPkgFSPath=/Users/myuser/go/pkg/mod/github.com/stevenferrer/solr-go@v0.4.0 version=v3.7.0                                                                                                                                                                                                                                       
2026-04-01T17:30:44.795671000-04:00 FTL app failed error="file not found" version=v3.7.0

The v2 file works fine with mockery2 and generates the interfaces without error, so I'm confused what's wrong?

Reproducer

1. Clone https://github.com/takanuva15/mockery3pkggen-error-mve
2. Generate interfaces using mockery v2: mockery
3. Generate interfaces using mockery v3 and observe error: mockery3 --config .mockery_v3.yml

Expected behavior

No error

Mockery version

v3.7.0

Installation Mechanism

• go get
• Pre-built release
• homebrew
• Other: [please describe]

Go version

go version go1.26.0 darwin/arm64

[LandonTClipp]

Can you describe what is the expected path you want for the github.com/stevenferrer/solr-go mocks?

This took me a while to understand. For your external repo being pulled in, the config templates are being rendered with this data:

ConfigDir:. 
InterfaceDir:/Users/lclipp/go/pkg/mod/github.com/stevenferrer/solr-go@v0.4.0 
InterfaceDirRelative:../../../go/pkg/mod/github.com/stevenferrer/solr-go@v0.4.0 
InterfaceFile:/Users/lclipp/go/pkg/mod/github.com/stevenferrer/solr-go@v0.4.0/request_sender.go 
InterfaceName:RequestSender 
Mock:Mock 
StructName:{{.InterfaceName}}Mock 
SrcPackageName:solr 
SrcPackagePath:github.com/stevenferrer/solr-go 
Template:testify

So dir: test/mocks/{{.InterfaceDirRelative}} becomes ../go/pkg/mod/github.com/stevenferrer/solr-go@v0.4.0 because it's equal to test/mocks/../../../go/pkg/mod/github.com/stevenferrer/solr-go@v0.4.0. This gets interpreted as relative to CWD, which when made absolute is:

/Users/lclipp/git/takanuva15/go/pkg/mod/github.com/stevenferrer/solr-go@v0.4.0

This path doesn't exist because it escaped outside of the original git repo through ../. That's not good :(

InterfaceDirRelative honestly has been more of a headache for me than I anticipated, especially when it comes to external repos like this. You're better off using {{.InterfaceDir}} or {{.SrcPackagePath}} depending on what you want the path to actually look like.

I will await your response and will update the documentation to make this clearer depending on where your confusion was.

[LandonTClipp]

Also to be clear, I'm open to trying to make the behavior identical between v2 and v3 but this topic has come up before and I recall it being hard due to fixing this requiring backwards incompatible changes. I don't remember off the top of my head what that was, I'll have to look it up.

[takanuva15]

I was expecting it to generate in the same location as v2 does it: <repository root>/test/mocks/github.com/stevenferrer/solr-go/*

I don't mind using InterfaceDir or SrcPackagePath, but what do I put in my config so it generates in the same directory with the same folder pattern like v2 is doing it?

[LandonTClipp]

Using dir: "test/mocks/{{.SrcPackagePath}}" for external repos and dir: "test/mocks/{{.InterfaceDirRelative}}" for internal packages should work. InterfaceDirRelative seems broken for external packages so I need to consider how to fix this.

[takanuva15]

Ok cool, that's working for me. If you remember what were the "backwards incompatible changes" you mentioned, please let us know. Otherwise maybe you can just make a new template method like {{ .InterfaceDirRelativeRemappingExternalOnCwd }} that does the same behavior as v2 (ie normal folder path for internal, <root>/github.com/stevenferrer/solr-go/* for external). Then deprecate or rename the original InterfaceDirRelative method to indicate that it uses absolute paths based on PC install location

My final v3 file for future reference (committed to my MVE repo for live demo):

dir: test/mocks/{{.SrcPackagePath}}
include-auto-generated: false
structname: '{{.InterfaceName}}Mock'
template: testify
template-data:
  unroll-variadic: true
packages:
  github.com/stevenferrer/solr-go:
    config:
      all: true
      recursive: true
  mockery3pkggen:
    config:
      all: true
      dir: "test/mocks/{{.InterfaceDirRelative}}"

[LandonTClipp]

Yes I do need to look into what was the difference. I marked this as a bug so I just need to investigate. I actually think it might be possible to fix the parameter without creating a new one because as you've seen here, it's currently totally broken for external repos.

[takanuva15]

@LandonTClipp is it fine if I tried to raise a PR to fix this? (I didn't want to step over you if you already had a fix branch open)

[LandonTClipp]

Absolutely feel free to submit a PR. I haven't started on anything yet. All we need to do is add a generic "is this repo path outside of our go.mod" function, and if so, make InterfaceDirRelative equal to the fully qualified repo path instead of the relative directory path. I think v2 might have simply tried to see if it could make the repo path relative to go.mod for that check. Once that logic is added then I think it should be at parity with v2.