build(deps): bump github.com/Abirdcfly/dupword from 0.1.1 to 0.1.3 (#5062)

Co-authored-by: Fernandez Ludovic <ldez@users.noreply.github.com>

.github/workflows/pr.yml

@@ -39,11 +39,9 @@ jobs:
           # ex:
           # - 1.18beta1 -> 1.18.0-beta.1
           # - 1.18rc1 -> 1.18.0-rc.1
-          # TODO(ldez) must be changed after the first release of golangci-lint with go1.23
-          # go-version: ${{ env.GO_VERSION }}
-          go-version: '1.22'
+          go-version: ${{ env.GO_VERSION }}
       - name: lint
-        uses: golangci/golangci-lint-action@v6.1.0
+        uses: golangci/golangci-lint-action@v6.1.1
         with:
           version: latest
 

.golangci.next.reference.yml

@@ -890,6 +890,9 @@ linters-settings:
       # Detects input and output parameters that have a type of pointer to referential type.
       # https://go-critic.com/overview.html#ptrToRefParam
       - ptrToRefParam
+      # Detects append all its data while range it.
+      # https://go-critic.com/overview.html#rangeAppendAll
+      - rangeAppendAll
       # Detects expensive copies of `for` loop range expressions.
       # https://go-critic.com/overview.html#rangeExprCopy
       - rangeExprCopy
@@ -1086,6 +1089,7 @@ linters-settings:
       - preferStringWriter
       - preferWriteByte
       - ptrToRefParam
+      - rangeAppendAll
       - rangeExprCopy
       - rangeValCopy
       - redundantSprint
@@ -2115,14 +2119,17 @@ linters-settings:
     min-complexity: 4
 
   nilnil:
+    # In addition, detect opposite situation (simultaneous return of non-nil error and valid value).
+    # Default: false
+    detect-opposite: true
     # List of return types to check.
-    # Default: ["ptr", "func", "iface", "map", "chan", "uintptr", "unsafeptr"]
+    # Default: ["chan", "func", "iface", "map", "ptr", "uintptr", "unsafeptr"]
     checked-types:
-      - ptr
+      - chan
       - func
       - iface
       - map
-      - chan
+      - ptr
       - uintptr
       - unsafeptr
 
@@ -3269,7 +3276,9 @@ linters-settings:
       - blank-import
       - bool-compare
       - compares
+      - contains
       - empty
+      - encoded-compare
       - error-is-as
       - error-nil
       - expected-actual
@@ -3279,6 +3288,7 @@ linters-settings:
       - len
       - negative-positive
       - nil-compare
+      - regexp
       - require-error
       - suite-broken-parallel
       - suite-dont-use-pkg
@@ -3292,15 +3302,17 @@ linters-settings:
     disable-all: true
     # Enable checkers by name
     # (in addition to default
-    #   blank-import, bool-compare, compares, empty, error-is-as, error-nil, expected-actual, go-require, float-compare,
-    #   formatter, len, negative-positive, nil-compare, require-error, suite-broken-parallel, suite-dont-use-pkg,
-    #   suite-extra-assert-call, suite-subtest-run, useless-assert
+    #   blank-import, bool-compare, compares, contains, empty, encoded-compare, error-is-as, error-nil, expected-actual,
+    #   go-require, float-compare, formatter, len, negative-positive, nil-compare, regexp, require-error,
+    #   suite-broken-parallel, suite-dont-use-pkg, suite-extra-assert-call, suite-subtest-run, useless-assert
     # ).
     enable:
       - blank-import
       - bool-compare
       - compares
+      - contains
       - empty
+      - encoded-compare
       - error-is-as
       - error-nil
       - expected-actual
@@ -3310,6 +3322,7 @@ linters-settings:
       - len
       - negative-positive
       - nil-compare
+      - regexp
       - require-error
       - suite-broken-parallel
       - suite-dont-use-pkg

docs/src/docs/welcome/install.mdx

@@ -132,31 +132,26 @@ Colored output:
 docker run -t --rm -v $(pwd):/app -w /app golangci/golangci-lint:{.LatestVersion} golangci-lint run -v
 ```
 
-### Install from Source
+### Install from Sources
 
-Note: such `go install`/`go get` installation aren't guaranteed to work. We recommend using binary installation.
+Such `go install`/`go get` or "tools pattern" installations aren't guaranteed to work.
 
-<details>
-<summary>Why?</summary>
+We recommend using binary installation.
 
-`go install`/`go get` installation isn't recommended because of the following points:
+Those installations aren't recommended because of the following points:
 
-1. Some users use `-u` flag for `go get`, which upgrades our dependencies. Resulting configuration wasn't tested and isn't guaranteed to work.
-2. [`go.mod`](https://github.com/golangci/golangci-lint/blob/master/go.mod) replacement directive doesn't apply. It means a user will be using patched version of `golangci-lint` if we use such replacements.
-3. We've encountered a lot of issues with Go modules hashes.
-4. It allows installation from `master` branch which can't be considered stable.
-5. It's slower than binary installation.
-
-</details>
-
-<div style="margin-top: 2em;">
+1. Those installations are compiling golangci-lint locally, the Go version used to build will depend on your local Go version.
+2. Some users use `-u` flag for `go get`, which upgrades our dependencies. Resulting binary was not tested and is not guaranteed to work.
+3. When using "tools pattern", the dependencies of a tool can modify the dependencies of another. Resulting binary was not tested and is not guaranteed to work.
+4. We've encountered issues with Go modules hashes due to unexpected recreation of dependency tags.
+5. `go.mod` replacement directives don't apply transitively. It means a user will be using patched version of `golangci-lint` if we use such replacements.
+6. It allows installation from main branch which can't be considered stable.
+7. It's slower than binary installation.
 
 ```sh
 go install github.com/golangci/golangci-lint/cmd/golangci-lint@{.LatestVersion}
 ```
 
-</div>
-
 ## Next
 
 [Quick Start: how to use `golangci-lint`](/welcome/quick-start/).

go.mod

@@ -6,10 +6,10 @@ require (
 	4d63.com/gocheckcompilerdirectives v1.2.1
 	4d63.com/gochecknoglobals v0.2.1
 	github.com/4meepo/tagalign v1.3.4
-	github.com/Abirdcfly/dupword v0.1.1
-	github.com/Antonboom/errname v0.1.13
-	github.com/Antonboom/nilnil v0.1.9
-	github.com/Antonboom/testifylint v1.4.3
+	github.com/Abirdcfly/dupword v0.1.3
+	github.com/Antonboom/errname v1.0.0
+	github.com/Antonboom/nilnil v1.0.0
+	github.com/Antonboom/testifylint v1.5.0
 	github.com/BurntSushi/toml v1.4.1-0.20240526193622-a339e1f7089c
 	github.com/Crocmagnon/fatcontext v0.5.2
 	github.com/Djarvur/go-err113 v0.0.0-20210108212216-aea10b59be24
@@ -38,7 +38,7 @@ require (
 	github.com/firefart/nonamedreturns v1.0.5
 	github.com/fzipp/gocyclo v0.6.0
 	github.com/ghostiam/protogetter v0.3.8
-	github.com/go-critic/go-critic v0.11.4
+	github.com/go-critic/go-critic v0.11.5
 	github.com/go-viper/mapstructure/v2 v2.2.1
 	github.com/go-xmlfmt/xmlfmt v1.1.2
 	github.com/gofrs/flock v0.12.1
@@ -126,7 +126,7 @@ require (
 	go-simpler.org/sloglint v0.7.2
 	go.uber.org/automaxprocs v1.6.0
 	golang.org/x/exp v0.0.0-20240909161429-701f63a606c0
-	golang.org/x/tools v0.25.0
+	golang.org/x/tools v0.26.0
 	gopkg.in/yaml.v3 v3.0.1
 	honnef.co/go/tools v0.5.1
 	mvdan.cc/gofumpt v0.7.0
@@ -192,7 +192,7 @@ require (
 	golang.org/x/exp/typeparams v0.0.0-20240314144324-c7f7c6466f7f // indirect
 	golang.org/x/mod v0.21.0 // indirect
 	golang.org/x/sync v0.8.0 // indirect
-	golang.org/x/sys v0.25.0 // indirect
+	golang.org/x/sys v0.26.0 // indirect
 	golang.org/x/text v0.18.0 // indirect
 	google.golang.org/protobuf v1.34.2 // indirect
 	gopkg.in/ini.v1 v1.67.0 // indirect

go.sum

@@ -37,14 +37,14 @@ cloud.google.com/go/storage v1.10.0/go.mod h1:FLPqc6j+Ki4BU591ie1oL6qBQGu2Bl/tZ9
 dmitri.shuralyov.com/gpu/mtl v0.0.0-20190408044501-666a987793e9/go.mod h1:H6x//7gZCb22OMCxBHrMx7a5I7Hp++hsVxbQ4BYO7hU=
 github.com/4meepo/tagalign v1.3.4 h1:P51VcvBnf04YkHzjfclN6BbsopfJR5rxs1n+5zHt+w8=
 github.com/4meepo/tagalign v1.3.4/go.mod h1:M+pnkHH2vG8+qhE5bVc/zeP7HS/j910Fwa9TUSyZVI0=
-github.com/Abirdcfly/dupword v0.1.1 h1:Bsxe0fIw6OwBtXMIncaTxCLHYO5BB+3mcsR5E8VXloY=
-github.com/Abirdcfly/dupword v0.1.1/go.mod h1:B49AcJdTYYkpd4HjgAcutNGG9HZ2JWwKunH9Y2BA6sM=
-github.com/Antonboom/errname v0.1.13 h1:JHICqsewj/fNckzrfVSe+T33svwQxmjC+1ntDsHOVvM=
-github.com/Antonboom/errname v0.1.13/go.mod h1:uWyefRYRN54lBg6HseYCFhs6Qjcy41Y3Jl/dVhA87Ns=
-github.com/Antonboom/nilnil v0.1.9 h1:eKFMejSxPSA9eLSensFmjW2XTgTwJMjZ8hUHtV4s/SQ=
-github.com/Antonboom/nilnil v0.1.9/go.mod h1:iGe2rYwCq5/Me1khrysB4nwI7swQvjclR8/YRPl5ihQ=
-github.com/Antonboom/testifylint v1.4.3 h1:ohMt6AHuHgttaQ1xb6SSnxCeK4/rnK7KKzbvs7DmEck=
-github.com/Antonboom/testifylint v1.4.3/go.mod h1:+8Q9+AOLsz5ZiQiiYujJKs9mNz398+M6UgslP4qgJLA=
+github.com/Abirdcfly/dupword v0.1.3 h1:9Pa1NuAsZvpFPi9Pqkd93I7LIYRURj+A//dFd5tgBeE=
+github.com/Abirdcfly/dupword v0.1.3/go.mod h1:8VbB2t7e10KRNdwTVoxdBaxla6avbhGzb8sCTygUMhw=
+github.com/Antonboom/errname v1.0.0 h1:oJOOWR07vS1kRusl6YRSlat7HFnb3mSfMl6sDMRoTBA=
+github.com/Antonboom/errname v1.0.0/go.mod h1:gMOBFzK/vrTiXN9Oh+HFs+e6Ndl0eTFbtsRTSRdXyGI=
+github.com/Antonboom/nilnil v1.0.0 h1:n+v+B12dsE5tbAqRODXmEKfZv9j2KcTBrp+LkoM4HZk=
+github.com/Antonboom/nilnil v1.0.0/go.mod h1:fDJ1FSFoLN6yoG65ANb1WihItf6qt9PJVTn/s2IrcII=
+github.com/Antonboom/testifylint v1.5.0 h1:dlUIsDMtCrZWUnvkaCz3quJCoIjaGi41GzjPBGkkJ8A=
+github.com/Antonboom/testifylint v1.5.0/go.mod h1:wqaJbu0Blb5Wag2wv7Z5xt+CIV+eVLxtGZrlK13z3AE=
 github.com/BurntSushi/toml v0.3.1/go.mod h1:xHWCNGjB5oqiDr8zfno3MHue2Ht5sIBksp03qcyfWMU=
 github.com/BurntSushi/toml v1.4.1-0.20240526193622-a339e1f7089c h1:pxW6RcqyfI9/kWtOwnv/G+AzdKuy2ZrqINhenH4HyNs=
 github.com/BurntSushi/toml v1.4.1-0.20240526193622-a339e1f7089c/go.mod h1:ukJfTF/6rtPPRCnwkur4qwRxa8vTRFBF0uk2lLoLwho=
@@ -149,8 +149,8 @@ github.com/fzipp/gocyclo v0.6.0 h1:lsblElZG7d3ALtGMx9fmxeTKZaLLpU8mET09yN4BBLo=
 github.com/fzipp/gocyclo v0.6.0/go.mod h1:rXPyn8fnlpa0R2csP/31uerbiVBugk5whMdlyaLkLoA=
 github.com/ghostiam/protogetter v0.3.8 h1:LYcXbYvybUyTIxN2Mj9h6rHrDZBDwZloPoKctWrFyJY=
 github.com/ghostiam/protogetter v0.3.8/go.mod h1:WZ0nw9pfzsgxuRsPOFQomgDVSWtDLJRfQJEhsGbmQMA=
-github.com/go-critic/go-critic v0.11.4 h1:O7kGOCx0NDIni4czrkRIXTnit0mkyKOCePh3My6OyEU=
-github.com/go-critic/go-critic v0.11.4/go.mod h1:2QAdo4iuLik5S9YG0rT4wcZ8QxwHYkrr6/2MWAiv/vc=
+github.com/go-critic/go-critic v0.11.5 h1:TkDTOn5v7EEngMxu8KbuFqFR43USaaH8XRJLz1jhVYA=
+github.com/go-critic/go-critic v0.11.5/go.mod h1:wu6U7ny9PiaHaZHcvMDmdysMqvDem162Rh3zWTrqk8M=
 github.com/go-gl/glfw v0.0.0-20190409004039-e6da0acd62b1/go.mod h1:vR7hzQXu2zJy9AVAgeJqvqgH9Q5CA+iKCZ2gyEVpxRU=
 github.com/go-gl/glfw/v3.3/glfw v0.0.0-20191125211704-12ad95a8df72/go.mod h1:tQ2UAYgL5IevRw8kRxooKSPJfGvJ9fJQFa0TUsXzTg8=
 github.com/go-gl/glfw/v3.3/glfw v0.0.0-20200222043503-6f7a984d4dc4/go.mod h1:tQ2UAYgL5IevRw8kRxooKSPJfGvJ9fJQFa0TUsXzTg8=
@@ -697,8 +697,8 @@ golang.org/x/net v0.1.0/go.mod h1:Cx3nUiGt4eDBEyega/BKRp+/AlGL8hYe7U9odMt2Cco=
 golang.org/x/net v0.2.0/go.mod h1:KqCZLdyyvdV855qA2rE3GC2aiw5xGR5TEjj8smXukLY=
 golang.org/x/net v0.5.0/go.mod h1:DivGGAXEgPSlEBzxGzZI+ZLohi+xUj054jfeKui00ws=
 golang.org/x/net v0.6.0/go.mod h1:2Tu9+aMcznHK/AK1HMvgo6xiTLG5rD5rZLDS+rp2Bjs=
-golang.org/x/net v0.29.0 h1:5ORfpBpCs4HzDYoodCDBbwHzdR5UrLBZ3sOnUJmFoHo=
-golang.org/x/net v0.29.0/go.mod h1:gLkgy8jTGERgjzMic6DS9+SP0ajcu6Xu3Orq/SpETg0=
+golang.org/x/net v0.30.0 h1:AcW1SDZMkb8IpzCdQUaIq2sP4sZ4zw+55h6ynffypl4=
+golang.org/x/net v0.30.0/go.mod h1:2wGyMJ5iFasEhkwi13ChkO/t1ECNC4X4eBKkVFyYFlU=
 golang.org/x/oauth2 v0.0.0-20180821212333-d2e6202438be/go.mod h1:N/0e6XlmueqKjAGxoOufVs8QHGRruUQn6yWY3a++T0U=
 golang.org/x/oauth2 v0.0.0-20190226205417-e64efc72b421/go.mod h1:gOpvHmFTYa4IltrdGE7lF6nIHvwfUNPOp7c8zoXwtLw=
 golang.org/x/oauth2 v0.0.0-20190604053449-0f29369cfe45/go.mod h1:gOpvHmFTYa4IltrdGE7lF6nIHvwfUNPOp7c8zoXwtLw=
@@ -777,8 +777,8 @@ golang.org/x/sys v0.5.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.6.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.8.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.11.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.25.0 h1:r+8e+loiHxRqhXVl6ML1nO3l1+oFoWbnlu2Ehimmi34=
-golang.org/x/sys v0.25.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
+golang.org/x/sys v0.26.0 h1:KHjCJyddX0LoSTb3J+vWpupP9p0oznkqVk/IfjymZbo=
+golang.org/x/sys v0.26.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
 golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
 golang.org/x/term v0.0.0-20210927222741-03fcf44c2211/go.mod h1:jbD1KX2456YbFQfuXm/mYQcufACuNUgVhRMnK/tPxf8=
 golang.org/x/term v0.1.0/go.mod h1:jbD1KX2456YbFQfuXm/mYQcufACuNUgVhRMnK/tPxf8=
@@ -860,8 +860,8 @@ golang.org/x/tools v0.2.0/go.mod h1:y4OqIKeOV/fWJetJ8bXPU1sEVniLMIyDAZWeHdV+NTA=
 golang.org/x/tools v0.3.0/go.mod h1:/rWhSS2+zyEVwoJf8YAX6L2f0ntZ7Kn/mGgAWcipA5k=
 golang.org/x/tools v0.5.0/go.mod h1:N+Kgy78s5I24c24dU8OfWNEotWjutIs8SnJvn5IDq+k=
 golang.org/x/tools v0.6.0/go.mod h1:Xwgl3UAJ/d3gWutnCtw505GrjyAbvKui8lOU390QaIU=
-golang.org/x/tools v0.25.0 h1:oFU9pkj/iJgs+0DT+VMHrx+oBKs/LJMV+Uvg78sl+fE=
-golang.org/x/tools v0.25.0/go.mod h1:/vtpO8WL1N9cQC3FN5zPqb//fRXskFHbLKk4OW1Q7rg=
+golang.org/x/tools v0.26.0 h1:v/60pFQmzmT9ExmjDv2gGIfi3OqfKoEP6I5+umXlbnQ=
+golang.org/x/tools v0.26.0/go.mod h1:TPVVj70c7JJ3WCazhD8OdXcZg/og+b9+tH/KxylGwH0=
 golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 golang.org/x/xerrors v0.0.0-20191011141410-1b5146add898/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=

jsonschema/golangci.next.jsonschema.json

@@ -68,6 +68,7 @@
         "preferStringWriter",
         "preferWriteByte",
         "ptrToRefParam",
+        "rangeAppendAll",
         "rangeExprCopy",
         "rangeValCopy",
         "redundantSprint",
@@ -2188,13 +2189,18 @@
           "type": "object",
           "additionalProperties": false,
           "properties": {
+            "detect-opposite": {
+              "type": "boolean",
+              "description": "In addition, detect opposite situation (simultaneous return of non-nil error and valid value).",
+              "default": false
+            },
             "checked-types": {
               "type": "array",
               "description": "List of return types to check.",
               "items": {
-                "enum": ["ptr", "func", "iface", "map", "chan", "uintptr", "unsafeptr"]
+                "enum": ["chan", "func", "iface", "map", "ptr", "uintptr", "unsafeptr"]
               },
-              "default": ["ptr", "func", "iface", "map", "chan", "uintptr", "unsafeptr"]
+              "default": ["chan", "func", "iface", "map", "ptr", "uintptr", "unsafeptr"]
             }
           }
         },
@@ -2905,7 +2911,9 @@
                   "blank-import",
                   "bool-compare",
                   "compares",
+                  "contains",
                   "empty",
+                  "encoded-compare",
                   "error-is-as",
                   "error-nil",
                   "expected-actual",
@@ -2915,6 +2923,7 @@
                   "len",
                   "negative-positive",
                   "nil-compare",
+                  "regexp",
                   "require-error",
                   "suite-broken-parallel",
                   "suite-dont-use-pkg",
@@ -2928,16 +2937,19 @@
                 "blank-import",
                 "bool-compare",
                 "compares",
+                "contains",
                 "empty",
+                "encoded-compare",
                 "error-is-as",
                 "error-nil",
                 "expected-actual",
                 "float-compare",
-                "float-compare",
+                "formatter",
                 "go-require",
                 "len",
                 "negative-positive",
                 "nil-compare",
+                "regexp",
                 "require-error",
                 "suite-broken-parallel",
                 "suite-dont-use-pkg",
@@ -2954,7 +2966,9 @@
                   "blank-import",
                   "bool-compare",
                   "compares",
+                  "contains",
                   "empty",
+                  "encoded-compare",
                   "error-is-as",
                   "error-nil",
                   "expected-actual",
@@ -2964,6 +2978,7 @@
                   "len",
                   "negative-positive",
                   "nil-compare",
+                  "regexp",
                   "require-error",
                   "suite-broken-parallel",
                   "suite-dont-use-pkg",

pkg/config/linters_settings.go

@@ -733,7 +733,8 @@ type NestifSettings struct {
 }
 
 type NilNilSettings struct {
-	CheckedTypes []string `mapstructure:"checked-types"`
+	DetectOpposite bool     `mapstructure:"detect-opposite"`
+	CheckedTypes   []string `mapstructure:"checked-types"`
 }
 
 type NlreturnSettings struct {

pkg/goanalysis/runner_loadingpackage.go

@@ -4,6 +4,7 @@ import (
 	"errors"
 	"fmt"
 	"go/ast"
+	"go/build"
 	"go/parser"
 	"go/scanner"
 	"go/types"
@@ -164,6 +165,7 @@ func (lp *loadingPackage) loadFromSource(loadMode LoadMode) error {
 			pkg.Errors = append(pkg.Errors, lp.convertError(err)...)
 		},
 		GoVersion: rv, // TODO(ldez) temporary workaround
+		Sizes:     types.SizesFor(build.Default.Compiler, build.Default.GOARCH),
 	}
 
 	_ = types.NewChecker(tc, pkg.Fset, pkg.Types, pkg.TypesInfo).Files(pkg.Syntax)

pkg/golinters/errname/testdata/errname.go

@@ -11,11 +11,11 @@ var (
 	ErrEndOfFile = errors.New("end of file")
 	errEndOfFile = errors.New("end of file")
 
-	EndOfFileError = errors.New("end of file") // want "the variable name `EndOfFileError` should conform to the `ErrXxx` format"
-	ErrorEndOfFile = errors.New("end of file") // want "the variable name `ErrorEndOfFile` should conform to the `ErrXxx` format"
-	EndOfFileErr   = errors.New("end of file") // want "the variable name `EndOfFileErr` should conform to the `ErrXxx` format"
-	endOfFileError = errors.New("end of file") // want "the variable name `endOfFileError` should conform to the `errXxx` format"
-	errorEndOfFile = errors.New("end of file") // want "the variable name `errorEndOfFile` should conform to the `errXxx` format"
+	EndOfFileError = errors.New("end of file") // want "the sentinel error name `EndOfFileError` should conform to the `ErrXxx` format"
+	ErrorEndOfFile = errors.New("end of file") // want "the sentinel error name `ErrorEndOfFile` should conform to the `ErrXxx` format"
+	EndOfFileErr   = errors.New("end of file") // want "the sentinel error name `EndOfFileErr` should conform to the `ErrXxx` format"
+	endOfFileError = errors.New("end of file") // want "the sentinel error name `endOfFileError` should conform to the `errXxx` format"
+	errorEndOfFile = errors.New("end of file") // want "the sentinel error name `errorEndOfFile` should conform to the `errXxx` format"
 )
 
 const maxSize = 256
@@ -24,8 +24,8 @@ var (
 	ErrOutOfSize = fmt.Errorf("out of size (max %d)", maxSize)
 	errOutOfSize = fmt.Errorf("out of size (max %d)", maxSize)
 
-	OutOfSizeError = fmt.Errorf("out of size (max %d)", maxSize) // want "the variable name `OutOfSizeError` should conform to the `ErrXxx` format"
-	outOfSizeError = fmt.Errorf("out of size (max %d)", maxSize) // want "the variable name `outOfSizeError` should conform to the `errXxx` format"
+	OutOfSizeError = fmt.Errorf("out of size (max %d)", maxSize) // want "the sentinel error name `OutOfSizeError` should conform to the `ErrXxx` format"
+	outOfSizeError = fmt.Errorf("out of size (max %d)", maxSize) // want "the sentinel error name `outOfSizeError` should conform to the `errXxx` format"
 )
 
 func errInsideFuncIsNotSentinel() error {
@@ -42,14 +42,14 @@ type DNSConfigError struct{}
 
 func (D DNSConfigError) Error() string { return "DNS config error" }
 
-type someTypeWithoutPtr struct{}           // want "the type name `someTypeWithoutPtr` should conform to the `xxxError` format"
+type someTypeWithoutPtr struct{}           // want "the error type name `someTypeWithoutPtr` should conform to the `xxxError` format"
 func (s someTypeWithoutPtr) Error() string { return "someTypeWithoutPtr" }
 
-type SomeTypeWithoutPtr struct{}           // want "the type name `SomeTypeWithoutPtr` should conform to the `XxxError` format"
+type SomeTypeWithoutPtr struct{}           // want "the error type name `SomeTypeWithoutPtr` should conform to the `XxxError` format"
 func (s SomeTypeWithoutPtr) Error() string { return "SomeTypeWithoutPtr" }
 
-type someTypeWithPtr struct{}            // want "the type name `someTypeWithPtr` should conform to the `xxxError` format"
+type someTypeWithPtr struct{}            // want "the error type name `someTypeWithPtr` should conform to the `xxxError` format"
 func (s *someTypeWithPtr) Error() string { return "someTypeWithPtr" }
 
-type SomeTypeWithPtr struct{}            // want "the type name `SomeTypeWithPtr` should conform to the `XxxError` format"
+type SomeTypeWithPtr struct{}            // want "the error type name `SomeTypeWithPtr` should conform to the `XxxError` format"
 func (s *SomeTypeWithPtr) Error() string { return "SomeTypeWithPtr" }

pkg/golinters/nilnil/nilnil.go

@@ -1,8 +1,6 @@
 package nilnil
 
 import (
-	"strings"
-
 	"github.com/Antonboom/nilnil/pkg/analyzer"
 	"golang.org/x/tools/go/analysis"
 
@@ -10,13 +8,16 @@ import (
 	"github.com/golangci/golangci-lint/pkg/goanalysis"
 )
 
-func New(cfg *config.NilNilSettings) *goanalysis.Linter {
+func New(settings *config.NilNilSettings) *goanalysis.Linter {
 	a := analyzer.New()
 
 	cfgMap := make(map[string]map[string]any)
-	if cfg != nil && len(cfg.CheckedTypes) != 0 {
+	if settings != nil {
 		cfgMap[a.Name] = map[string]any{
-			"checked-types": strings.Join(cfg.CheckedTypes, ","),
+			"detect-opposite": settings.DetectOpposite,
+		}
+		if len(settings.CheckedTypes) != 0 {
+			cfgMap[a.Name]["checked-types"] = settings.CheckedTypes
 		}
 	}
 

pkg/golinters/nilnil/testdata/nilnil.go

@@ -3,8 +3,11 @@ package testdata
 
 import (
 	"bytes"
+	"errors"
+	"fmt"
 	"go/token"
 	"io"
+	"net"
 	"net/http"
 	"os"
 	"unsafe"
@@ -13,100 +16,100 @@ import (
 type User struct{}
 
 func primitivePtr() (*int, error) {
-	return nil, nil // want "return both the `nil` error and invalid value: use a sentinel error instead"
+	return nil, nil // want "return both a `nil` error and an invalid value: use a sentinel error instead"
 }
 
 func structPtr() (*User, error) {
-	return nil, nil // want "return both the `nil` error and invalid value: use a sentinel error instead"
+	return nil, nil // want "return both a `nil` error and an invalid value: use a sentinel error instead"
 }
 
 func emptyStructPtr() (*struct{}, error) {
-	return nil, nil // want "return both the `nil` error and invalid value: use a sentinel error instead"
+	return nil, nil // want "return both a `nil` error and an invalid value: use a sentinel error instead"
 }
 
 func anonymousStructPtr() (*struct{ ID string }, error) {
-	return nil, nil // want "return both the `nil` error and invalid value: use a sentinel error instead"
+	return nil, nil // want "return both a `nil` error and an invalid value: use a sentinel error instead"
 }
 
 func unsafePtr() (unsafe.Pointer, error) {
-	return nil, nil // want "return both the `nil` error and invalid value: use a sentinel error instead"
+	return nil, nil // want "return both a `nil` error and an invalid value: use a sentinel error instead"
 }
 
 func uintPtr() (uintptr, error) {
-	return 0, nil // want "return both the `nil` error and invalid value: use a sentinel error instead"
+	return 0, nil // want "return both a `nil` error and an invalid value: use a sentinel error instead"
 }
 
 func uintPtr0b() (uintptr, error) {
-	return 0b0, nil // want "return both the `nil` error and invalid value: use a sentinel error instead"
+	return 0b0, nil // want "return both a `nil` error and an invalid value: use a sentinel error instead"
 }
 
 func uintPtr0x() (uintptr, error) {
-	return 0x00, nil // want "return both the `nil` error and invalid value: use a sentinel error instead"
+	return 0x00, nil // want "return both a `nil` error and an invalid value: use a sentinel error instead"
 }
 
 func uintPtr0o() (uintptr, error) {
-	return 0o000, nil // want "return both the `nil` error and invalid value: use a sentinel error instead"
+	return 0o000, nil // want "return both a `nil` error and an invalid value: use a sentinel error instead"
 }
 
 func chBi() (chan int, error) {
-	return nil, nil // want "return both the `nil` error and invalid value: use a sentinel error instead"
+	return nil, nil // want "return both a `nil` error and an invalid value: use a sentinel error instead"
 }
 
 func chIn() (chan<- int, error) {
-	return nil, nil // want "return both the `nil` error and invalid value: use a sentinel error instead"
+	return nil, nil // want "return both a `nil` error and an invalid value: use a sentinel error instead"
 }
 
 func chOut() (<-chan int, error) {
-	return nil, nil // want "return both the `nil` error and invalid value: use a sentinel error instead"
+	return nil, nil // want "return both a `nil` error and an invalid value: use a sentinel error instead"
 }
 
 func fun() (func(), error) {
-	return nil, nil // want "return both the `nil` error and invalid value: use a sentinel error instead"
+	return nil, nil // want "return both a `nil` error and an invalid value: use a sentinel error instead"
 }
 
 func funWithArgsAndResults() (func(a, b, c int) (int, int), error) {
-	return nil, nil // want "return both the `nil` error and invalid value: use a sentinel error instead"
+	return nil, nil // want "return both a `nil` error and an invalid value: use a sentinel error instead"
 }
 
 func iface() (interface{}, error) {
-	return nil, nil // want "return both the `nil` error and invalid value: use a sentinel error instead"
+	return nil, nil // want "return both a `nil` error and an invalid value: use a sentinel error instead"
 }
 
 func anyType() (any, error) {
-	return nil, nil // want "return both the `nil` error and invalid value: use a sentinel error instead"
+	return nil, nil // want "return both a `nil` error and an invalid value: use a sentinel error instead"
 }
 
 func m1() (map[int]int, error) {
-	return nil, nil // want "return both the `nil` error and invalid value: use a sentinel error instead"
+	return nil, nil // want "return both a `nil` error and an invalid value: use a sentinel error instead"
 }
 
 func m2() (map[int]*User, error) {
-	return nil, nil // want "return both the `nil` error and invalid value: use a sentinel error instead"
+	return nil, nil // want "return both a `nil` error and an invalid value: use a sentinel error instead"
 }
 
 type mapAlias = map[int]*User
 
 func m3() (mapAlias, error) {
-	return nil, nil // want "return both the `nil` error and invalid value: use a sentinel error instead"
+	return nil, nil // want "return both a `nil` error and an invalid value: use a sentinel error instead"
 }
 
 type Storage struct{}
 
 func (s *Storage) GetUser() (*User, error) {
-	return nil, nil // want "return both the `nil` error and invalid value: use a sentinel error instead"
+	return nil, nil // want "return both a `nil` error and an invalid value: use a sentinel error instead"
 }
 
 func ifReturn() (*User, error) {
 	var s Storage
 	if _, err := s.GetUser(); err != nil {
-		return nil, nil // want "return both the `nil` error and invalid value: use a sentinel error instead"
+		return nil, nil // want "return both a `nil` error and an invalid value: use a sentinel error instead"
 	}
 	return new(User), nil
 }
 
 func forReturn() (*User, error) {
 	for {
-		return nil, nil // want "return both the `nil` error and invalid value: use a sentinel error instead"
+		return nil, nil // want "return both a `nil` error and an invalid value: use a sentinel error instead"
 	}
 }
 
@@ -114,15 +117,15 @@ func multipleReturn() (*User, error) {
 	var s Storage
 
 	if _, err := s.GetUser(); err != nil {
-		return nil, nil // want "return both the `nil` error and invalid value: use a sentinel error instead"
+		return nil, nil // want "return both a `nil` error and an invalid value: use a sentinel error instead"
 	}
 
 	if _, err := s.GetUser(); err != nil {
-		return nil, nil // want "return both the `nil` error and invalid value: use a sentinel error instead"
+		return nil, nil // want "return both a `nil` error and an invalid value: use a sentinel error instead"
 	}
 
 	if _, err := s.GetUser(); err != nil {
-		return nil, nil // want "return both the `nil` error and invalid value: use a sentinel error instead"
+		return nil, nil // want "return both a `nil` error and an invalid value: use a sentinel error instead"
 	}
 
 	return new(User), nil
@@ -130,11 +133,11 @@ func multipleReturn() (*User, error) {
 
 func nested() {
 	_ = func() (*User, error) {
-		return nil, nil // want "return both the `nil` error and invalid value: use a sentinel error instead"
+		return nil, nil // want "return both a `nil` error and an invalid value: use a sentinel error instead"
 	}
 
 	_, _ = func() (*User, error) {
-		return nil, nil // want "return both the `nil` error and invalid value: use a sentinel error instead"
+		return nil, nil // want "return both a `nil` error and an invalid value: use a sentinel error instead"
 	}()
 }
 
@@ -145,7 +148,7 @@ func deeplyNested() {
 				_ = func() (*User, error) {
 					_ = func() {}
 					_ = func() int { return 0 }
-					return nil, nil // want "return both the `nil` error and invalid value: use a sentinel error instead"
+					return nil, nil // want "return both a `nil` error and an invalid value: use a sentinel error instead"
 				}
 			}
 			return 0
@@ -159,31 +162,31 @@ type MyError interface {
 }
 
 func myError() (*User, MyError) {
-	return nil, nil // want "return both the `nil` error and invalid value: use a sentinel error instead"
+	return nil, nil // want "return both a `nil` error and an invalid value: use a sentinel error instead"
 }
 
 // Types.
 
 func structPtrTypeExtPkg() (*os.File, error) {
-	return nil, nil // want "return both the `nil` error and invalid value: use a sentinel error instead"
+	return nil, nil // want "return both a `nil` error and an invalid value: use a sentinel error instead"
 }
 
 func primitivePtrTypeExtPkg() (*token.Token, error) {
-	return nil, nil // want "return both the `nil` error and invalid value: use a sentinel error instead"
+	return nil, nil // want "return both a `nil` error and an invalid value: use a sentinel error instead"
 }
 
 func funcTypeExtPkg() (http.HandlerFunc, error) {
-	return nil, nil // want "return both the `nil` error and invalid value: use a sentinel error instead"
+	return nil, nil // want "return both a `nil` error and an invalid value: use a sentinel error instead"
 }
 
 func ifaceTypeExtPkg() (io.Closer, error) {
-	return nil, nil // want "return both the `nil` error and invalid value: use a sentinel error instead"
+	return nil, nil // want "return both a `nil` error and an invalid value: use a sentinel error instead"
 }
 
 type closerAlias = io.Closer
 
 func ifaceTypeAliasedExtPkg() (closerAlias, error) {
-	return nil, nil // want "return both the `nil` error and invalid value: use a sentinel error instead"
+	return nil, nil // want "return both a `nil` error and an invalid value: use a sentinel error instead"
 }
 
 type (
@@ -195,29 +198,29 @@ type (
 )
 
 func structPtrType() (StructPtrType, error) {
-	return nil, nil // want "return both the `nil` error and invalid value: use a sentinel error instead"
+	return nil, nil // want "return both a `nil` error and an invalid value: use a sentinel error instead"
 }
 
 func primitivePtrType() (PrimitivePtrType, error) {
-	return nil, nil // want "return both the `nil` error and invalid value: use a sentinel error instead"
+	return nil, nil // want "return both a `nil` error and an invalid value: use a sentinel error instead"
 }
 
 func channelType() (ChannelType, error) {
-	return nil, nil // want "return both the `nil` error and invalid value: use a sentinel error instead"
+	return nil, nil // want "return both a `nil` error and an invalid value: use a sentinel error instead"
 }
 
 func funcType() (FuncType, error) {
-	return nil, nil // want "return both the `nil` error and invalid value: use a sentinel error instead"
+	return nil, nil // want "return both a `nil` error and an invalid value: use a sentinel error instead"
 }
 
 func ifaceType() (Checker, error) {
-	return nil, nil // want "return both the `nil` error and invalid value: use a sentinel error instead"
+	return nil, nil // want "return both a `nil` error and an invalid value: use a sentinel error instead"
 }
 
 type checkerAlias = Checker
 
 func ifaceTypeAliased() (checkerAlias, error) {
-	return nil, nil // want "return both the `nil` error and invalid value: use a sentinel error instead"
+	return nil, nil // want "return both a `nil` error and an invalid value: use a sentinel error instead"
 }
 
 type (
@@ -226,7 +229,7 @@ type (
 )
 
 func ptrIntegerType() (PtrIntegerType, error) {
-	return nil, nil // want "return both the `nil` error and invalid value: use a sentinel error instead"
+	return nil, nil // want "return both a `nil` error and an invalid value: use a sentinel error instead"
 }
 
 // Not checked at all.
@@ -317,3 +320,57 @@ func implicitNil3() (*User, error) {
 	return nil, wrap(nil)
 }
 func wrap(err error) error { return err }
+
+// Opposite.
+
+func primitivePtrTypeOpposite() (*int, error) {
+	if false {
+		return nil, io.EOF
+	}
+	return new(int), errors.New("validation failed")
+}
+
+func structPtrTypeOpposite() (*User, error) {
+	if false {
+		return nil, io.EOF
+	}
+	return new(User), fmt.Errorf("invalid %v", 42)
+}
+
+func unsafePtrOpposite() (unsafe.Pointer, error) {
+	if false {
+		return nil, io.EOF
+	}
+	var i int
+	return unsafe.Pointer(&i), io.EOF
+}
+
+func uintPtrOpposite() (uintptr, error) {
+	if false {
+		return 0, io.EOF
+	}
+	return 0xc82000c290, wrap(io.EOF)
+}
+
+func channelTypeOpposite() (ChannelType, error) {
+	if false {
+		return nil, io.EOF
+	}
+	return make(ChannelType), fmt.Errorf("wrapped: %w", io.EOF)
+}
+
+func funcTypeOpposite() (FuncType, error) {
+	if false {
+		return nil, io.EOF
+	}
+	return func(i int) int {
+		return 0
+	}, errors.New("no func type, please")
+}
+
+func ifaceTypeOpposite() (io.Reader, error) {
+	if false {
+		return nil, io.EOF
+	}
+	return new(bytes.Buffer), new(net.AddrError)
+}

pkg/golinters/nilnil/testdata/nilnil_detect_opposite.go

@@ -0,0 +1,83 @@
+//golangcitest:args -Enilnil
+//golangcitest:config_path testdata/nilnil_detect_opposite.yml
+package testdata
+
+import (
+	"bytes"
+	"errors"
+	"fmt"
+	"io"
+	"net"
+	"unsafe"
+)
+
+func primitivePtrTypeOpposite() (*int, error) {
+	if false {
+		return nil, io.EOF
+	}
+	return new(int), errors.New("validation failed") // want "return both a non-nil error and a valid value: use separate returns instead"
+}
+
+func structPtrTypeOpposite() (*User, error) {
+	if false {
+		return nil, io.EOF
+	}
+	return new(User), fmt.Errorf("invalid %v", 42) // want "return both a non-nil error and a valid value: use separate returns instead"
+}
+
+func unsafePtrOpposite() (unsafe.Pointer, error) {
+	if false {
+		return nil, io.EOF
+	}
+	var i int
+	return unsafe.Pointer(&i), io.EOF // want "return both a non-nil error and a valid value: use separate returns instead"
+}
+
+func uintPtrOpposite() (uintptr, error) {
+	if false {
+		return 0, io.EOF
+	}
+	return 0xc82000c290, wrap(io.EOF) // want "return both a non-nil error and a valid value: use separate returns instead"
+}
+
+func channelTypeOpposite() (ChannelType, error) {
+	if false {
+		return nil, io.EOF
+	}
+	return make(ChannelType), fmt.Errorf("wrapped: %w", io.EOF) // want "return both a non-nil error and a valid value: use separate returns instead"
+}
+
+func funcTypeOpposite() (FuncType, error) {
+	if false {
+		return nil, io.EOF
+	}
+	return func(i int) int { // want "return both a non-nil error and a valid value: use separate returns instead"
+		return 0
+	}, errors.New("no func type, please")
+}
+
+func ifaceTypeOpposite() (io.Reader, error) {
+	if false {
+		return nil, io.EOF
+	}
+	return new(bytes.Buffer), new(net.AddrError) // want "return both a non-nil error and a valid value: use separate returns instead"
+}
+
+type (
+	User             struct{}
+	StructPtrType    *User
+	PrimitivePtrType *int
+	ChannelType      chan int
+	FuncType         func(int) int
+	Checker          interface{ Check() }
+)
+
+func wrap(err error) error { return err }
+
+func structPtr() (*int, error) {
+	return nil, nil // want "return both a `nil` error and an invalid value: use a sentinel error instead"
+}
+
+func structPtrValid() (*int, error) {
+	return new(int), nil
+}

pkg/golinters/nilnil/testdata/nilnil_detect_opposite.yml

@@ -0,0 +1,3 @@
+linters-settings:
+  nilnil:
+    detect-opposite: true

pkg/golinters/nilnil/testdata/nilnil_pointers_only.go

@@ -0,0 +1,39 @@
+//golangcitest:args -Enilnil
+//golangcitest:config_path testdata/nilnil_pointers_only.yml
+package testdata
+
+import "unsafe"
+
+type User struct{}
+
+func primitivePtr() (*int, error) {
+	return nil, nil // want "return both a `nil` error and an invalid value: use a sentinel error instead"
+}
+
+func structPtr() (*User, error) {
+	return nil, nil // want "return both a `nil` error and an invalid value: use a sentinel error instead"
+}
+
+func unsafePtr() (unsafe.Pointer, error) {
+	return nil, nil
+}
+
+func uintPtr0o() (uintptr, error) {
+	return 0o000, nil // want "return both a `nil` error and an invalid value: use a sentinel error instead"
+}
+
+func chBi() (chan int, error) {
+	return nil, nil
+}
+
+func fun() (func(), error) {
+	return nil, nil
+}
+
+func anyType() (any, error) {
+	return nil, nil
+}
+
+func m1() (map[int]int, error) {
+	return nil, nil
+}

pkg/golinters/nilnil/testdata/nilnil_pointers_only.yml

@@ -0,0 +1,5 @@
+linters-settings:
+  nilnil:
+    checked-types:
+      - ptr
+      - uintptr

pkg/printers/printer_test.go

@@ -225,5 +225,5 @@ func TestPrinter_Print_multiple(t *testing.T) {
 	goldenJSON, err := os.ReadFile(filepath.Join("testdata", "golden-json.json"))
 	require.NoError(t, err)
 
-	assert.Equal(t, string(goldenJSON), stdOutBuffer.String())
+	assert.JSONEq(t, string(goldenJSON), stdOutBuffer.String())
 }