errcheck does not work on Close

[Seb-C]

Welcome

• Yes, I'm using a binary release within 2 latest major releases. Only such installations are supported.
• Yes, I've searched similar issues on GitHub and didn't find any.
• Yes, I've read the typecheck section of the FAQ (https://golangci-lint.run/usage/faq/#why-do-you-have-typecheck-errors).
• Yes, I've tried with the standalone linter if available (e.g., gocritic, go vet, etc.). (https://golangci-lint.run/usage/linters/)

Description of the problem

errcheck does not report any problem related to any call to the Close method, despite having an appropriate configuration. I have a use case where those errors are significant and must be detected and handled.

When I run errcheck -blank -asserts ./... (latest version of this repository) manually without golangci-lint, I get the expected issues reported:

cmd/main.go:30:18:      defer file.Close()
cmd/main.go:31:12:      file.Close()
cmd/main.go:32:2:       _ = file.Close()
cmd/main.go:34:5:       _, _ = os.Create("bar")

When I do the same thing via golangci-lint, I don't get the expected errors, only the last one:

cmd/main.go:34:5: Error return value of `os.Create` is not checked (errcheck)
        _, _ = os.Create("bar")
           ^

Version of golangci-lint

$ golangci-lint --version
golangci-lint has version 1.55.2 built with go1.21.3 from e3c2265f on 2023-11-03T12:59:25Z

Configuration

linters:
  disable-all: true
  enable:
    - errcheck
linters-settings:
  errcheck:
    check-type-assertions: true
    check-blank: true
    disable-default-exclusions: true

Go environment

$ go version && go env
go version go1.21.3 linux/amd64
GO111MODULE=''
GOARCH='amd64'
GOBIN=''
GOCACHE='/home/sebastien/.cache/go-build'
GOENV='/home/sebastien/.config/go/env'
GOEXE=''
GOEXPERIMENT=''
GOFLAGS=''
GOHOSTARCH='amd64'
GOHOSTOS='linux'
GOINSECURE=''
GOMODCACHE='/home/sebastien/go/pkg/mod'
GONOPROXY=''
GONOSUMDB=''
GOOS='linux'
GOPATH='/home/sebastien/go'
GOPRIVATE=''
GOPROXY='https://proxy.golang.org,direct'
GOROOT='/usr/lib/go-1.21'
GOSUMDB='sum.golang.org'
GOTMPDIR=''
GOTOOLCHAIN='auto'
GOTOOLDIR='/usr/lib/go-1.21/pkg/tool/linux_amd64'
GOVCS=''
GOVERSION='go1.21.3'
GCCGO='gccgo'
GOAMD64='v1'
AR='ar'
CC='gcc'
CXX='g++'
CGO_ENABLED='1'
GOMOD='/home/sebastien/Programmation/astral-divide/go.mod'
GOWORK=''
CGO_CFLAGS='-O2 -g'
CGO_CPPFLAGS=''
CGO_CXXFLAGS='-O2 -g'
CGO_FFLAGS='-O2 -g'
CGO_LDFLAGS='-O2 -g'
PKG_CONFIG='pkg-config'
GOGCCFLAGS='-fPIC -m64 -pthread -Wl,--no-gc-sections -fmessage-length=0 -ffile-prefix-map=/tmp/go-build2728494281=/tmp/go-build -gno-record-gcc-switches'

Verbose output of running

$ golangci-lint cache clean
$ golangci-lint run -v
INFO [config_reader] Config search paths: [./ /[redacted path to project] /[redacted path to parent dir of the project] /[redacted path to home] /home /] 
INFO [config_reader] Used config file .golangci.yml 
INFO [lintersdb] Active 1 linters: [errcheck]     
INFO [loader] Go packages loading at mode 575 (types_sizes|exports_file|files|imports|compiled_files|deps|name) took 432.683742ms 
INFO [runner/filename_unadjuster] Pre-built 0 adjustments in 9.728706ms 
INFO [linters_context/goanalysis] analyzers took 17.777243ms with top 10 stages: errcheck: 17.58221ms, typecheck: 195.033µs 
INFO [runner] Issues before processing: 41, after processing: 1 
INFO [runner] Processors filtering stat (out/in): diff: 1/1, max_same_issues: 1/1, path_shortener: 1/1, path_prettifier: 41/41, skip_dirs: 41/41, identifier_marker: 41/41, max_per_file_from_linter: 1/1, max_from_linter: 1/1, severity-rules: 1/1, fixer: 1/1, sort_results: 1/1, cgo: 41/41, filename_unadjuster: 41/41, skip_files: 41/41, nolint: 1/1, source_code: 1/1, uniq_by_line: 1/1, path_prefixer: 1/1, autogenerated_exclude: 41/41, exclude: 41/41, exclude-rules: 1/41 
INFO [runner] processing took 1.333199ms with stages: path_prettifier: 374.815µs, identifier_marker: 328.037µs, autogenerated_exclude: 224.271µs, nolint: 216.868µs, skip_dirs: 89.639µs, exclude-rules: 60.534µs, source_code: 29.686µs, cgo: 2.645µs, max_same_issues: 1.413µs, path_shortener: 1.122µs, uniq_by_line: 982ns, filename_unadjuster: 881ns, max_from_linter: 712ns, fixer: 290ns, max_per_file_from_linter: 271ns, skip_files: 271ns, exclude: 201ns, severity-rules: 190ns, diff: 161ns, sort_results: 140ns, path_prefixer: 70ns 
INFO [runner] linters took 149.488983ms with stages: goanalysis_metalinter: 148.101482ms 
cmd/main.go:34:5: Error return value of `os.Create` is not checked (errcheck)
        _, _ = os.Create("bar")
           ^
INFO File cache stats: 1 entries of total size 10.1KiB 
INFO Memory: 7 samples, avg is 40.8MB, max is 98.6MB 
INFO Execution took 595.449448ms

A minimal reproducible example or link to a public repository

	file, err := os.Create("foo")
	if err != nil {
		panic(err)
	}

	// I expect an error for each case below
	defer file.Close()
	file.Close()
	_ = file.Close()

	_, _ = os.Create("bar") // I only get an error here

Validation

• Yes, I've included all information above (version, config, etc.).

[boring-cyborg]

Hey, thank you for opening your first Issue ! 🙂 If you would like to contribute we have a guide for contributors.

[ldez]

Hello,

This report is ignored by default, this is the exclusion rule EXC0001.
It was flagged as "Almost all programs ignore errors on these functions and in most cases it's ok".

To show the report, you have to disable the default exclusions:

issues:
  exclude-use-default: false

or you have to disable this specific exclusion rule:

issues:
  include:
    - EXC001

duplicate of #3976