build: enable custom linting rules with ruleguard via gocritic

.golangci.yml

@@ -100,10 +100,45 @@ linters-settings:
     # as documented here: https://staticcheck.io/docs/configuration/options/#checks
     checks: ["all", "-ST1000", "-ST1003", "-ST1016", "-ST1020", "-ST1021", "-ST1022", "-ST1023"]
   gocritic:
-    disabled-checks:
+    # Enable all default checks with some exceptions and some additions (commented).
-      - appendAssign
+    # Cannot use both enabled-checks and disabled-checks, so must specify all to be used.
-      - captLocal
+    disable-all: true
-      - commentFormatting
+    enabled-checks:
-      - exitAfterDefer
+      #- appendAssign # Enabled by default
-      - ifElseChain
+      - argOrder
-      - singleCaseSwitch
+      - assignOp
+      - badCall
+      - badCond
+      #- captLocal # Enabled by default
+      - caseOrder
+      - codegenComment
+      #- commentFormatting # Enabled by default
+      - defaultCaseOrder
+      - deprecatedComment
+      - dupArg
+      - dupBranchBody
+      - dupCase
+      - dupSubExpr
+      - elseif
+      #- exitAfterDefer # Enabled by default
+      - flagDeref
+      - flagName
+      #- ifElseChain # Enabled by default
+      - mapKey
+      - newDeref
+      - offBy1
+      - regexpMust
+      - ruleguard # Not enabled by default
+      #- singleCaseSwitch # Enabled by default
+      - sloppyLen
+      - sloppyTypeAssert
+      - switchTrue
+      - typeSwitchVar
+      - underef
+      - unlambda
+      - unslice
+      - valSwap
+      - wrapperFunc
+    settings:
+      ruleguard:
+        rules: "${configDir}/bin/rules.go"

bin/rules.go

@@ -0,0 +1,51 @@
+// Ruleguard file implementing custom linting rules.
+//
+// Note that when used from golangci-lint (using the gocritic linter configured
+// with the ruleguard check), because rule files are not handled by
+// golangci-lint itself, changes will not invalidate the golangci-lint cache,
+// and you must manually clean to cache (golangci-lint cache clean) for them to
+// be considered, as explained here:
+// https://www.quasilyte.dev/blog/post/ruleguard/#using-from-the-golangci-lint
+//
+// Note that this file is ignored from build with a build constraint, but using
+// a different than "ignore" to avoid go mod tidy making dsl an indirect
+// dependency, as explained here:
+// https://github.com/quasilyte/go-ruleguard?tab=readme-ov-file#troubleshooting
+
+//go:build ruleguard
+// +build ruleguard
+
+// Package gorules implementing custom linting rules using ruleguard
+package gorules
+
+import "github.com/quasilyte/go-ruleguard/dsl"
+
+// Suggest rewriting "log.(Print|Fatal|Panic)(f|ln)?" to
+// "fs.(Printf|Fatalf|Panicf)", and do it if running golangci-lint with
+// argument --fix. The suggestion wraps a single non-string single argument or
+// variadic arguments in fmt.Sprint to be compatible with format string
+// argument of fs functions.
+//
+// Caveats:
+//   - After applying the suggestions, imports may have to be fixed manually,
+//     removing unused "log", adding "github.com/rclone/rclone/fs" and "fmt",
+//     and if there was a variable named "fs" or "fmt" in the scope the name
+//     clash must be fixed.
+//   - Suggested code is incorrect when within fs package itself, due to the
+//     "fs."" prefix. Could handle it using condition
+//     ".Where(m.File().PkgPath.Matches(`github.com/rclone/rclone/fs`))"
+//     but not sure how to avoid duplicating all checks with and without this
+//     condition so haven't bothered yet.
+func useFsLog(m dsl.Matcher) {
+	m.Match(`log.Print($x)`, `log.Println($x)`).Where(m["x"].Type.Is(`string`)).Suggest(`fs.Logf(nil, $x)`)
+	m.Match(`log.Print($*args)`, `log.Println($*args)`).Suggest(`fs.Logf(nil, fmt.Sprint($args))`)
+	m.Match(`log.Printf($*args)`).Suggest(`fs.Logf(nil, $args)`)
+
+	m.Match(`log.Fatal($x)`, `log.Fatalln($x)`).Where(m["x"].Type.Is(`string`)).Suggest(`fs.Fatalf(nil, $x)`)
+	m.Match(`log.Fatal($*args)`, `log.Fatalln($*args)`).Suggest(`fs.Fatalf(nil, fmt.Sprint($args))`)
+	m.Match(`log.Fatalf($*args)`).Suggest(`fs.Fatalf(nil, $args)`)
+
+	m.Match(`log.Panic($x)`, `log.Panicln($x)`).Where(m["x"].Type.Is(`string`)).Suggest(`fs.Panicf(nil, $x)`)
+	m.Match(`log.Panic($*args)`, `log.Panicln($*args)`).Suggest(`fs.Panicf(nil, fmt.Sprint($args))`)
+	m.Match(`log.Panicf($*args)`).Suggest(`fs.Panicf(nil, $args)`)
+}

go.mod

@@ -58,6 +58,7 @@ require (
 	github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2
 	github.com/prometheus/client_golang v1.19.1
 	github.com/putdotio/go-putio/putio v0.0.0-20200123120452-16d982cac2b8
+	github.com/quasilyte/go-ruleguard/dsl v0.3.22
 	github.com/rclone/gofakes3 v0.0.3-0.20240807151802-e80146f8de87
 	github.com/rfjakob/eme v1.1.2
 	github.com/rivo/uniseg v0.4.7

go.sum

@@ -511,6 +511,8 @@ github.com/prometheus/procfs v0.12.0 h1:jluTpSng7V9hY0O2R9DzzJHYb2xULk9VTR1V1R/k
 github.com/prometheus/procfs v0.12.0/go.mod h1:pcuDEFsWDnvcgNzo4EEweacyhjeA9Zk3cnaOZAZEfOo=
 github.com/putdotio/go-putio/putio v0.0.0-20200123120452-16d982cac2b8 h1:Y258uzXU/potCYnQd1r6wlAnoMB68BiCkCcCnKx1SH8=
 github.com/putdotio/go-putio/putio v0.0.0-20200123120452-16d982cac2b8/go.mod h1:bSJjRokAHHOhA+XFxplld8w2R/dXLH7Z3BZ532vhFwU=
+github.com/quasilyte/go-ruleguard/dsl v0.3.22 h1:wd8zkOhSNr+I+8Qeciml08ivDt1pSXe60+5DqOpCjPE=
+github.com/quasilyte/go-ruleguard/dsl v0.3.22/go.mod h1:KeCP03KrjuSO0H1kTuZQCWlQPulDV6YMIXmpQss17rU=
 github.com/quic-go/qtls-go1-20 v0.4.1 h1:D33340mCNDAIKBqXuAvexTNMUByrYmFYVfKfDN5nfFs=
 github.com/quic-go/qtls-go1-20 v0.4.1/go.mod h1:X9Nh97ZL80Z+bX/gUXMbipO6OxdiDi58b/fMC9mAL+k=
 github.com/quic-go/quic-go v0.40.1 h1:X3AGzUNFs0jVuO3esAGnTfvdgvL4fq655WaOi1snv1Q=