chore: replace viper with koanf

go.mod

@@ -11,13 +11,17 @@ require (
 	github.com/creack/pty v1.1.23
 	github.com/gobwas/glob v0.2.3
 	github.com/google/go-cmp v0.6.0
+	github.com/knadh/koanf/parsers/json v0.1.0
+	github.com/knadh/koanf/parsers/toml/v2 v2.1.0
+	github.com/knadh/koanf/parsers/yaml v0.1.0
+	github.com/knadh/koanf/providers/fs v0.1.0
+	github.com/knadh/koanf/v2 v2.1.1
 	github.com/mattn/go-tty v0.0.7
 	github.com/mitchellh/mapstructure v1.5.0
 	github.com/rogpeppe/go-internal v1.12.0
 	github.com/schollz/progressbar/v3 v3.14.6
 	github.com/spf13/afero v1.11.0
 	github.com/spf13/cobra v1.8.1
-	github.com/spf13/viper v1.19.0
 	github.com/stretchr/testify v1.9.0
 	gopkg.in/alessio/shellescape.v1 v1.0.0-20170105083845-52074bc9df61
 )
@@ -26,37 +30,31 @@ require (
 	github.com/aymanbagabas/go-osc52/v2 v2.0.1 // indirect
 	github.com/charmbracelet/x/ansi v0.1.4 // indirect
 	github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc // indirect
+	github.com/go-viper/mapstructure/v2 v2.1.0 // indirect
+	github.com/knadh/koanf/maps v0.1.1 // indirect
+	github.com/kr/pretty v0.3.1 // indirect
 	github.com/mitchellh/colorstring v0.0.0-20190213212951-d06e56a500db // indirect
+	github.com/mitchellh/copystructure v1.2.0 // indirect
+	github.com/mitchellh/reflectwalk v1.0.2 // indirect
 	github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2 // indirect
-	github.com/sagikazarmark/locafero v0.4.0 // indirect
-	github.com/sagikazarmark/slog-shim v0.1.0 // indirect
-	github.com/sourcegraph/conc v0.3.0 // indirect
-	go.uber.org/atomic v1.9.0 // indirect
-	go.uber.org/multierr v1.9.0 // indirect
-	golang.org/x/exp v0.0.0-20230905200255-921286631fa9 // indirect
 	golang.org/x/tools v0.13.0 // indirect
+	gopkg.in/check.v1 v1.0.0-20190902080502-41f04d3bba15 // indirect
 )
 
 require (
 	github.com/alessio/shellescape v1.4.1 // indirect
 	github.com/fatih/color v1.14.1 // indirect
-	github.com/fsnotify/fsnotify v1.7.0 // indirect
-	github.com/hashicorp/hcl v1.0.0 // indirect
 	github.com/inconshreveable/mousetrap v1.1.0 // indirect
 	github.com/lucasb-eyer/go-colorful v1.2.0 // indirect
-	github.com/magiconair/properties v1.8.7 // indirect
 	github.com/mattn/go-colorable v0.1.13 // indirect
 	github.com/mattn/go-isatty v0.0.20
 	github.com/mattn/go-runewidth v0.0.16 // indirect
 	github.com/muesli/termenv v0.15.2 // indirect
 	github.com/pelletier/go-toml/v2 v2.2.3
 	github.com/rivo/uniseg v0.4.7 // indirect
-	github.com/spf13/cast v1.6.0 // indirect
 	github.com/spf13/pflag v1.0.5 // indirect
-	github.com/subosito/gotenv v1.6.0 // indirect
 	golang.org/x/sys v0.22.0 // indirect
 	golang.org/x/term v0.22.0 // indirect
 	golang.org/x/text v0.14.0 // indirect
-	gopkg.in/ini.v1 v1.67.0 // indirect
 	gopkg.in/yaml.v3 v3.0.1
 )

go.sum

@@ -11,6 +11,7 @@ github.com/charmbracelet/lipgloss v0.13.0/go.mod h1:nw4zy0SBX/F/eAO1cWdcvy6qnkDU
 github.com/charmbracelet/x/ansi v0.1.4 h1:IEU3D6+dWwPSgZ6HBH+v6oUuZ/nVawMiWj5831KfiLM=
 github.com/charmbracelet/x/ansi v0.1.4/go.mod h1:dk73KoMTT5AX5BsX0KrqhsTqAnhZZoCBjs7dGWp4Ktw=
 github.com/cpuguy83/go-md2man/v2 v2.0.4/go.mod h1:tgQtvFlXSQOSOSIRvRPT7W67SCa46tRHOmNcaadrF8o=
+github.com/creack/pty v1.1.9/go.mod h1:oKZEueFk5CKHvIhNR5MUki03XCEU+Q6VDXinZuGJ33E=
 github.com/creack/pty v1.1.23 h1:4M6+isWdcStXEf15G/RbrMPOQj1dZ7HPZCGwE4kOeP0=
 github.com/creack/pty v1.1.23/go.mod h1:08sCNb52WyoAwi2QDyzUCTgcvVFhUzewun7wtTfvcwE=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
@@ -19,27 +20,33 @@ github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc h1:U9qPSI2PIWSS1
 github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/fatih/color v1.14.1 h1:qfhVLaG5s+nCROl1zJsZRxFeYrHLqWroPOQ8BWiNb4w=
 github.com/fatih/color v1.14.1/go.mod h1:2oHN61fhTpgcxD3TSWCgKDiH1+x4OiDVVGH8WlgGZGg=
-github.com/frankban/quicktest v1.14.6 h1:7Xjx+VpznH+oBnejlPUj8oUpdxnVs4f8XU8WnHkI4W8=
-github.com/frankban/quicktest v1.14.6/go.mod h1:4ptaffx2x8+WTWXmUCuVU6aPUX1/Mz7zb5vbUoiM6w0=
-github.com/fsnotify/fsnotify v1.7.0 h1:8JEhPFa5W2WU7YfeZzPNqzMP6Lwt7L2715Ggo0nosvA=
-github.com/fsnotify/fsnotify v1.7.0/go.mod h1:40Bi/Hjc2AVfZrqy+aj+yEI+/bRxZnMJyTJwOpGvigM=
+github.com/go-viper/mapstructure/v2 v2.1.0 h1:gHnMa2Y/pIxElCH2GlZZ1lZSsn6XMtufpGyP1XxdC/w=
+github.com/go-viper/mapstructure/v2 v2.1.0/go.mod h1:oJDH3BJKyqBA2TXFhDsKDGDTlndYOZ6rGS0BRZIxGhM=
 github.com/gobwas/glob v0.2.3 h1:A4xDbljILXROh+kObIiy5kIaPYD8e96x1tgBhUI5J+Y=
 github.com/gobwas/glob v0.2.3/go.mod h1:d3Ez4x06l9bZtSvzIay5+Yzi0fmZzPgnTbPcKjJAkT8=
 github.com/google/go-cmp v0.6.0 h1:ofyhxvXcZhMsU5ulbFiLKl/XBFqE1GSq7atu8tAmTRI=
 github.com/google/go-cmp v0.6.0/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
-github.com/hashicorp/hcl v1.0.0 h1:0Anlzjpi4vEasTeNFn2mLJgTSwt0+6sfsiTG8qcWGx4=
-github.com/hashicorp/hcl v1.0.0/go.mod h1:E5yfLk+7swimpb2L/Alb/PJmXilQ/rhwaUYs4T20WEQ=
 github.com/inconshreveable/mousetrap v1.1.0 h1:wN+x4NVGpMsO7ErUn/mUI3vEoE6Jt13X2s0bqwp9tc8=
 github.com/inconshreveable/mousetrap v1.1.0/go.mod h1:vpF70FUmC8bwa3OWnCshd2FqLfsEA9PFc4w1p2J65bw=
 github.com/k0kubun/go-ansi v0.0.0-20180517002512-3bf9e2903213/go.mod h1:vNUNkEQ1e29fT/6vq2aBdFsgNPmy8qMdSay1npru+Sw=
+github.com/knadh/koanf/maps v0.1.1 h1:G5TjmUh2D7G2YWf5SQQqSiHRJEjaicvU0KpypqB3NIs=
+github.com/knadh/koanf/maps v0.1.1/go.mod h1:npD/QZY3V6ghQDdcQzl1W4ICNVTkohC8E73eI2xW4yI=
+github.com/knadh/koanf/parsers/json v0.1.0 h1:dzSZl5pf5bBcW0Acnu20Djleto19T0CfHcvZ14NJ6fU=
+github.com/knadh/koanf/parsers/json v0.1.0/go.mod h1:ll2/MlXcZ2BfXD6YJcjVFzhG9P0TdJ207aIBKQhV2hY=
+github.com/knadh/koanf/parsers/toml/v2 v2.1.0 h1:EUdIKIeezfDj6e1ABDhIjhbURUpyrP1HToqW6tz8R0I=
+github.com/knadh/koanf/parsers/toml/v2 v2.1.0/go.mod h1:0KtwfsWJt4igUTQnsn0ZjFWVrP80Jv7edTBRbQFd2ho=
+github.com/knadh/koanf/parsers/yaml v0.1.0 h1:ZZ8/iGfRLvKSaMEECEBPM1HQslrZADk8fP1XFUxVI5w=
+github.com/knadh/koanf/parsers/yaml v0.1.0/go.mod h1:cvbUDC7AL23pImuQP0oRw/hPuccrNBS2bps8asS0CwY=
+github.com/knadh/koanf/providers/fs v0.1.0 h1:9Hln9GS3bWTItAnGVFYyfkoAIxAFq7pvlF64pTNiDdQ=
+github.com/knadh/koanf/providers/fs v0.1.0/go.mod h1:Cva1yH8NBxkEeVZx8CUmF5TunbgO72E+GwqDbqpP2sE=
+github.com/knadh/koanf/v2 v2.1.1 h1:/R8eXqasSTsmDCsAyYj+81Wteg8AqrV9CP6gvsTsOmM=
+github.com/knadh/koanf/v2 v2.1.1/go.mod h1:4mnTRbZCK+ALuBXHZMjDfG9y714L7TykVnZkXbMU3Es=
 github.com/kr/pretty v0.3.1 h1:flRD4NNwYAUpkphVc1HcthR4KEIFJ65n8Mw5qdRn3LE=
 github.com/kr/pretty v0.3.1/go.mod h1:hoEshYVHaxMs3cyo3Yncou5ZscifuDolrwPKZanG3xk=
 github.com/kr/text v0.2.0 h1:5Nx0Ya0ZqY2ygV366QzturHI13Jq95ApcVaJBhpS+AY=
 github.com/kr/text v0.2.0/go.mod h1:eLer722TekiGuMkidMxC/pM04lWEeraHUUmBw8l2grE=
 github.com/lucasb-eyer/go-colorful v1.2.0 h1:1nnpGOrhyZZuNyfu1QjKiUICQ74+3FNCN69Aj6K7nkY=
 github.com/lucasb-eyer/go-colorful v1.2.0/go.mod h1:R4dSotOR9KMtayYi1e77YzuveK+i7ruzyGqttikkLy0=
-github.com/magiconair/properties v1.8.7 h1:IeQXZAiQcpL9mgcAe1Nu6cX9LLw6ExEHKjN0VQdvPDY=
-github.com/magiconair/properties v1.8.7/go.mod h1:Dhd985XPs7jluiymwWYZ0G4Z61jb3vdS329zhj2hYo0=
 github.com/mattn/go-colorable v0.1.13 h1:fFA4WZxdEF4tXPZVKMLwD8oUnCTTo08duU7wxecdEvA=
 github.com/mattn/go-colorable v0.1.13/go.mod h1:7S9/ev0klgBDR4GtXTXX8a3vIGJpMovkB8vQcUbaXHg=
 github.com/mattn/go-isatty v0.0.16/go.mod h1:kYGgaQfpe5nmfYZH+SKPsOc2e4SrIfOl2e/yFXSvRLM=
@@ -51,51 +58,39 @@ github.com/mattn/go-tty v0.0.7 h1:KJ486B6qI8+wBO7kQxYgmmEFDaFEE96JMBQ7h400N8Q=
 github.com/mattn/go-tty v0.0.7/go.mod h1:f2i5ZOvXBU/tCABmLmOfzLz9azMo5wdAaElRNnJKr+k=
 github.com/mitchellh/colorstring v0.0.0-20190213212951-d06e56a500db h1:62I3jR2EmQ4l5rM/4FEfDWcRD+abF5XlKShorW5LRoQ=
 github.com/mitchellh/colorstring v0.0.0-20190213212951-d06e56a500db/go.mod h1:l0dey0ia/Uv7NcFFVbCLtqEBQbrT4OCwCSKTEv6enCw=
+github.com/mitchellh/copystructure v1.2.0 h1:vpKXTN4ewci03Vljg/q9QvCGUDttBOGBIa15WveJJGw=
+github.com/mitchellh/copystructure v1.2.0/go.mod h1:qLl+cE2AmVv+CoeAwDPye/v+N2HKCj9FbZEVFJRxO9s=
 github.com/mitchellh/mapstructure v1.5.0 h1:jeMsZIYE/09sWLaz43PL7Gy6RuMjD2eJVyuac5Z2hdY=
 github.com/mitchellh/mapstructure v1.5.0/go.mod h1:bFUtVrKA4DC2yAKiSyO/QUcy7e+RRV2QTWOzhPopBRo=
+github.com/mitchellh/reflectwalk v1.0.2 h1:G2LzWKi524PWgd3mLHV8Y5k7s6XUvT0Gef6zxSIeXaQ=
+github.com/mitchellh/reflectwalk v1.0.2/go.mod h1:mSTlrgnPZtwu0c4WaC2kGObEpuNDbx0jmZXqmk4esnw=
 github.com/muesli/termenv v0.15.2 h1:GohcuySI0QmI3wN8Ok9PtKGkgkFIk7y6Vpb5PvrY+Wo=
 github.com/muesli/termenv v0.15.2/go.mod h1:Epx+iuz8sNs7mNKhxzH4fWXGNpZwUaJKRS1noLXviQ8=
 github.com/pelletier/go-toml/v2 v2.2.3 h1:YmeHyLY8mFWbdkNWwpr+qIL2bEqT0o95WSdkNHvL12M=
 github.com/pelletier/go-toml/v2 v2.2.3/go.mod h1:MfCQTFTvCcUyyvvwm1+G6H/jORL20Xlb6rzQu9GuUkc=
+github.com/pkg/diff v0.0.0-20210226163009-20ebb0f2a09e/go.mod h1:pJLUxLENpZxwdsKMEsNbx1VGcRFpLqf3715MtcvvzbA=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2 h1:Jamvg5psRIccs7FGNTlIRMkT8wgtp5eCXdBlqhYGL6U=
 github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/rivo/uniseg v0.2.0/go.mod h1:J6wj4VEh+S6ZtnVlnTBMWIodfgj8LQOQFoIToxlJtxc=
 github.com/rivo/uniseg v0.4.7 h1:WUdvkW8uEhrYfLC4ZzdpI2ztxP1I582+49Oc5Mq64VQ=
 github.com/rivo/uniseg v0.4.7/go.mod h1:FN3SvrM+Zdj16jyLfmOkMNblXMcoc8DfTHruCPUcx88=
+github.com/rogpeppe/go-internal v1.9.0/go.mod h1:WtVeX8xhTBvf0smdhujwtBcq4Qrzq/fJaraNFVN+nFs=
 github.com/rogpeppe/go-internal v1.12.0 h1:exVL4IDcn6na9z1rAb56Vxr+CgyK3nn3O+epU5NdKM8=
 github.com/rogpeppe/go-internal v1.12.0/go.mod h1:E+RYuTGaKKdloAfM02xzb0FW3Paa99yedzYV+kq4uf4=
 github.com/russross/blackfriday/v2 v2.1.0/go.mod h1:+Rmxgy9KzJVeS9/2gXHxylqXiyQDYRxCVz55jmeOWTM=
-github.com/sagikazarmark/locafero v0.4.0 h1:HApY1R9zGo4DBgr7dqsTH/JJxLTTsOt7u6keLGt6kNQ=
-github.com/sagikazarmark/locafero v0.4.0/go.mod h1:Pe1W6UlPYUk/+wc/6KFhbORCfqzgYEpgQ3O5fPuL3H4=
-github.com/sagikazarmark/slog-shim v0.1.0 h1:diDBnUNK9N/354PgrxMywXnAwEr1QZcOr6gto+ugjYE=
-github.com/sagikazarmark/slog-shim v0.1.0/go.mod h1:SrcSrq8aKtyuqEI1uvTDTK1arOWRIczQRv+GVI1AkeQ=
 github.com/schollz/progressbar/v3 v3.14.6 h1:GyjwcWBAf+GFDMLziwerKvpuS7ZF+mNTAXIB2aspiZs=
 github.com/schollz/progressbar/v3 v3.14.6/go.mod h1:Nrzpuw3Nl0srLY0VlTvC4V6RL50pcEymjy6qyJAaLa0=
-github.com/sourcegraph/conc v0.3.0 h1:OQTbbt6P72L20UqAkXXuLOj79LfEanQ+YQFNpLA9ySo=
-github.com/sourcegraph/conc v0.3.0/go.mod h1:Sdozi7LEKbFPqYX2/J+iBAM6HpqSLTASQIKqDmF7Mt0=
 github.com/spf13/afero v1.11.0 h1:WJQKhtpdm3v2IzqG8VMqrr6Rf3UYpEF239Jy9wNepM8=
 github.com/spf13/afero v1.11.0/go.mod h1:GH9Y3pIexgf1MTIWtNGyogA5MwRIDXGUr+hbWNoBjkY=
-github.com/spf13/cast v1.6.0 h1:GEiTHELF+vaR5dhz3VqZfFSzZjYbgeKDpBxQVS4GYJ0=
-github.com/spf13/cast v1.6.0/go.mod h1:ancEpBxwJDODSW/UG4rDrAqiKolqNNh2DX3mk86cAdo=
 github.com/spf13/cobra v1.8.1 h1:e5/vxKd/rZsfSJMUX1agtjeTDf+qv1/JdBF8gg5k9ZM=
 github.com/spf13/cobra v1.8.1/go.mod h1:wHxEcudfqmLYa8iTfL+OuZPbBZkmvliBWKIezN3kD9Y=
 github.com/spf13/pflag v1.0.5 h1:iy+VFUOCP1a+8yFto/drg2CJ5u0yRoB7fZw3DKv/JXA=
 github.com/spf13/pflag v1.0.5/go.mod h1:McXfInJRrz4CZXVZOBLb0bTZqETkiAhM9Iw0y3An2Bg=
-github.com/spf13/viper v1.19.0 h1:RWq5SEjt8o25SROyN3z2OrDB9l7RPd3lwTWU8EcEdcI=
-github.com/spf13/viper v1.19.0/go.mod h1:GQUN9bilAbhU/jgc1bKs99f/suXKeUMct8Adx5+Ntkg=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=
 github.com/stretchr/testify v1.9.0 h1:HtqpIVDClZ4nwg75+f6Lvsy/wHu+3BoSGCbBAcpTsTg=
 github.com/stretchr/testify v1.9.0/go.mod h1:r2ic/lqez/lEtzL7wO/rwa5dbSLXVDPFyf8C91i36aY=
-github.com/subosito/gotenv v1.6.0 h1:9NlTDc1FTs4qu0DDq7AEtTPNw6SVm7uBMsUCUjABIf8=
-github.com/subosito/gotenv v1.6.0/go.mod h1:Dk4QP5c2W3ibzajGcXpNraDfq2IrhjMIvMSWPKKo0FU=
-go.uber.org/atomic v1.9.0 h1:ECmE8Bn/WFTYwEW/bpKD3M8VtR/zQVbavAoalC1PYyE=
-go.uber.org/atomic v1.9.0/go.mod h1:fEN4uk6kAWBTFdckzkM89CLk9XfWZrxpCo0nPH17wJc=
-go.uber.org/multierr v1.9.0 h1:7fIwc/ZtS0q++VgcfqFDxSBZVv/Xo49/SYnDFupUwlI=
-go.uber.org/multierr v1.9.0/go.mod h1:X2jQV1h+kxSjClGpnseKVIxpmcjrj7MNnI0bnlfKTVQ=
-golang.org/x/exp v0.0.0-20230905200255-921286631fa9 h1:GoHiUyI/Tp2nVkLI2mCxVkOjsbSXD66ic0XW0js0R9g=
-golang.org/x/exp v0.0.0-20230905200255-921286631fa9/go.mod h1:S2oDrQGGwySpoQPVqRShND87VCbxmc6bL1Yd2oYrm6k=
 golang.org/x/sys v0.0.0-20220811171246-fbc7d0a398ab/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.6.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.22.0 h1:RI27ohtqKCnwULzJLqkv897zojh5/DwS/ENaMzUOaWI=
@@ -111,7 +106,5 @@ gopkg.in/alessio/shellescape.v1 v1.0.0-20170105083845-52074bc9df61/go.mod h1:IfM
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/check.v1 v1.0.0-20190902080502-41f04d3bba15 h1:YR8cESwS4TdDjEe65xsg0ogRM/Nc3DYOhEAlW+xobZo=
 gopkg.in/check.v1 v1.0.0-20190902080502-41f04d3bba15/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
-gopkg.in/ini.v1 v1.67.0 h1:Dgnx+6+nfE+IfzjUEISNeydPJh9AXNNsWbGP9KzCsOA=
-gopkg.in/ini.v1 v1.67.0/go.mod h1:pNLf8WUiyNEtQjuu5G5vTm06TEv9tsIgeAvK8hOrP4k=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
 gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

internal/config/command.go

@@ -4,7 +4,7 @@ import (
 	"errors"
 	"strings"
 
-	"github.com/spf13/viper"
+	"github.com/knadh/koanf/v2"
 
 	"github.com/evilmartians/lefthook/internal/git"
 	"github.com/evilmartians/lefthook/internal/system"
@@ -55,21 +55,21 @@ func (c Command) ExecutionPriority() int {
 	return c.Priority
 }
 
-func mergeCommands(base, extra *viper.Viper) (map[string]*Command, error) {
+func mergeCommands(base, extra *koanf.Koanf) (map[string]*Command, error) {
 	if base == nil && extra == nil {
 		return nil, nil
 	}
 
 	if base == nil {
-		return unmarshalCommands(extra.Sub("commands"))
+		return unmarshalCommands(extra.Cut("commands"))
 	}
 
 	if extra == nil {
-		return unmarshalCommands(base.Sub("commands"))
+		return unmarshalCommands(base.Cut("commands"))
 	}
 
-	commandsOrigin := base.Sub("commands")
-	commandsOverride := extra.Sub("commands")
+	commandsOrigin := base.Cut("commands")
+	commandsOverride := extra.Cut("commands")
 	if commandsOrigin == nil {
 		return unmarshalCommands(commandsOverride)
 	}
@@ -78,22 +78,22 @@ func mergeCommands(base, extra *viper.Viper) (map[string]*Command, error) {
 	}
 
 	runReplaces := make(map[string]*commandRunReplace)
-	for key := range commandsOrigin.AllSettings() {
+	for key := range commandsOrigin.Raw() {
 		var replace commandRunReplace
 
-		substructure := commandsOrigin.Sub(key)
+		substructure := commandsOrigin.Cut(key)
 		if substructure == nil {
 			continue
 		}
 
-		if err := substructure.Unmarshal(&replace); err != nil {
+		if err := substructure.Unmarshal("", &replace); err != nil {
 			return nil, err
 		}
 
 		runReplaces[key] = &replace
 	}
 
-	err := commandsOrigin.MergeConfigMap(commandsOverride.AllSettings())
+	err := commandsOrigin.Merge(commandsOverride)
 	if err != nil {
 		return nil, err
 	}
@@ -112,13 +112,9 @@ func mergeCommands(base, extra *viper.Viper) (map[string]*Command, error) {
 	return commands, nil
 }
 
-func unmarshalCommands(v *viper.Viper) (map[string]*Command, error) {
-	if v == nil {
-		return nil, nil
-	}
-
+func unmarshalCommands(k *koanf.Koanf) (map[string]*Command, error) {
 	commands := make(map[string]*Command)
-	if err := v.Unmarshal(&commands); err != nil {
+	if err := k.Unmarshal("", &commands); err != nil {
 		return nil, err
 	}
 

internal/config/hook.go

@@ -5,7 +5,7 @@ import (
 	"os"
 	"strings"
 
-	"github.com/spf13/viper"
+	"github.com/knadh/koanf/v2"
 
 	"github.com/evilmartians/lefthook/internal/git"
 	"github.com/evilmartians/lefthook/internal/system"
@@ -48,7 +48,7 @@ func (h *Hook) DoSkip(gitState git.State) bool {
 	return skipChecker.check(gitState, h.Skip, h.Only)
 }
 
-func unmarshalHooks(base, extra *viper.Viper) (*Hook, error) {
+func unmarshalHooks(base, extra *koanf.Koanf) (*Hook, error) {
 	if base == nil && extra == nil {
 		return nil, nil
 	}
@@ -71,12 +71,12 @@ func unmarshalHooks(base, extra *viper.Viper) (*Hook, error) {
 	if base == nil {
 		base = extra
 	} else if extra != nil {
-		if err = base.MergeConfigMap(extra.AllSettings()); err != nil {
+		if err = base.Merge(extra); err != nil {
 			return nil, err
 		}
 	}
 
-	if err := base.Unmarshal(&hook); err != nil {
+	if err := base.Unmarshal("", &hook); err != nil {
 		return nil, err
 	}