compile errors under 0.25.3

[svix-jbrown]

With 0.25.3 and go1.26.4, this tool fails to compile:

$ go run github.com/hashicorp/copywrite headers -d .. --config ../.copywrite.hcl
# github.com/hashicorp/copywrite/config
../../../go/pkg/mod/github.com/hashicorp/copywrite@v0.25.3/config/config.go:172:48: cannot use ko (variable of type *"github.com/knadh/koanf/v2".Koanf) as *"github.com/knadh/koanf".Koanf value in argument to posflag.ProviderWithFla

Worked fine with 0.25.2...

[thaolaptrinh]

Adding a root-cause analysis since I just hit this in a downstream project.

What broke

v0.25.3 does not compile:

# github.com/hashicorp/copywrite/config
copywrite@v0.25.3/config/config.go:172:48: cannot use ko (variable of type
*"github.com/knadh/koanf/v2".Koanf) as *"github.com/knadh/koanf".Koanf value
in argument to posflag.ProviderWithFlag

v0.25.2 builds cleanly.

Root cause

Commit 04fdad9 ("bump konaf 1.5.0 > 2.3.4") performed a partial koanf v2 migration. It moved the core import to github.com/knadh/koanf/v2 but left the providers/parsers imports on their v1 paths:

config/config.go:

"github.com/knadh/koanf/parsers/hcl"       // v1
"github.com/knadh/koanf/providers/confmap" // v1
"github.com/knadh/koanf/providers/file"    // v1
"github.com/knadh/koanf/providers/posflag" // v1
"github.com/knadh/koanf/v2"                // v2

github/github/client.go:

"github.com/knadh/koanf/parsers/dotenv" // v1
"github.com/knadh/koanf/parsers/yaml"   // v1
"github.com/knadh/koanf/providers/env"  // v1
"github.com/knadh/koanf/providers/file" // v1
"github.com/knadh/koanf/v2"             // v2

The v1 provider packages depend on koanf v1 internally, so posflag.ProviderWithFlag(...) expects a *koanf.Koanf (v1), while the code now passes a *koanf/v2.Koanf. Hence the type clash.

Why the "obvious" fix does not work

The instinct is to change the provider/parser imports to their v2 paths (github.com/knadh/koanf/v2/providers/posflag, etc.). That is not possible today: the koanf project ships providers/* and parsers/* as separate modules, and none of them have v2 module paths yet. The current latest tags are all v1.x:

• github.com/knadh/koanf/providers/posflag → latest v1.0.1
• github.com/knadh/koanf/providers/confmap → latest v1.0.0
• github.com/knadh/koanf/providers/file → latest v1.2.1
• github.com/knadh/koanf/providers/env → latest v1.1.0
• github.com/knadh/koanf/parsers/hcl → latest v1.0.0

The koanf/v2 module (v2.3.4) contains only the core (koanf.go, interfaces.go, options.go, getters.go, mock/) — no providers/ or parsers/ subdirectories.

In other words, bumping the core to koanf v2 was done before the koanf ecosystem itself published v2-compatible providers/parsers, so the migration cannot be finished downstream right now.

Suggested recovery

Either of:

1. Revert the koanf v2 bump (commit 04fdad9) and return to koanf v1.5.0 across the board, restoring v0.25.2's buildability, or
2. Wait for / coordinate with koanf to publish v2 module paths for providers/* and parsers/*, then complete the migration for all 7 imports (not just the core).

Workaround for consumers

Pin copywrite v0.25.2 and ignore v0.25.3 until a fixed release is out.