Staticcheck is go vet on steroids, applying a ton of static analysis
checks you might be used to from tools like ReSharper for C#.
This project is supported by patrons on Patreon. If you, too, would like to support the project's development, consider becoming a patron.
Staticcheck requires Go 1.6 or later.
go get honnef.co/go/staticcheck/cmd/staticcheck
Invoke staticcheck with one or more filenames, a directory, or a package named
by its import path. Staticcheck uses the same
import path syntax as
the go command and therefore
also supports relative import paths like ./.... Additionally the ...
wildcard can be used as suffix on relative and absolute file paths to recurse
into them.
The output of this tool is a list of suggestions in Vim quickfix format, which is accepted by lots of different editors.
The main purpose of staticcheck is editor integration, or workflow integration in general. For example, by running staticcheck when saving a file, one can quickly catch simple bugs without having to run the whole test suite or the program itself.
The tool shouldn't report any errors unless there are legitimate bugs - or very dubious constructs - in the code.
It is similar in nature to go vet, but has more checks that catch
bugs that would also be caught easily at runtime, to reduce the number
of edit, compile and debug cycles.
The following things are currently checked by staticcheck:
| Check | Description |
|---|---|
| SA1??? | Various misuses of the standard library |
| SA1000 | Invalid regular expression |
| SA1001 | Invalid template |
| SA1002 | Invalid format in time.Parse |
| SA1003 | Unsupported argument to functions in encoding/binary |
| SA1004 | Suspiciously small untyped constant in time.Sleep |
| SA1005 | Invalid first argument to exec.Command |
| SA1006 | Printf with dynamic first argument and no further arguments |
| SA1007 | Invalid URL in net/url.Parse |
| SA1008 | Non-canonical key in http.Header map |
| SA1010 | (*regexp.Regexp).FindAll called with n == 0, which will always return zero results |
| SA1011 | Various methods in the strings package expect valid UTF-8, but invalid input is provided |
| SA1012 | A nil context.Context is being passed to a function, consider using context.TODO instead |
| SA1013 | io.Seeker.Seek is being called with the whence constant as the first argument, but it should be the second |
| SA1014 | Non-pointer value passed to Unmarshal or Decode |
| SA1015 | Using time.Tick in a way that will leak. Consider using time.NewTicker, and only use time.Tick in tests, commands and endless functions |
| SA1016 | Trapping a signal that cannot be trapped |
| SA1017 | Channels used with signal.Notify should be buffered |
| SA1018 | strings.Replace called with n == 0, which does nothing |
| SA1019 | Using a deprecated function, variable, constant or field |
| SA1020 | Using an invalid host:port pair with a net.Listen-related function |
| SA1021 | Using bytes.Equal to compare two net.IP |
| SA2??? | Concurrency issues |
| SA2000 | sync.WaitGroup.Add called inside the goroutine, leading to a race condition |
| SA2001 | Empty critical section, did you mean to defer the unlock? |
| SA2002 | Called testing.T.FailNow or SkipNow in a goroutine, which isn't allowed |
| SA2003 | Deferred Lock right after locking, likely meant to defer Unlock instead |
| SA3??? | Testing issues |
| SA3000 | TestMain doesn't call os.Exit, hiding test failures |
| SA3001 | Assigning to b.N in benchmarks distorts the results |
| SA4??? | Code that isn't really doing anything |
| SA4000 | Boolean expression has identical expressions on both sides |
| SA4001 | &*x gets simplified to x, it does not copy x |
| SA4002 | Comparing strings with known different sizes has predictable results |
| SA4003 | Comparing unsigned values against negative values is pointless |
| SA4004 | The loop exits unconditionally after one iteration |
| SA4005 | Field assignment that will never be observed. Did you mean to use a pointer receiver? |
| SA4006 | A value assigned to a variable is never read before being overwritten. Forgotten error check or dead code? |
| SA4008 | The variable in the loop condition never changes, are you incrementing the wrong variable? |
| SA4009 | A function argument is overwritten before its first use |
| SA4010 | The result of append will never be observed anywhere |
| SA4011 | Break statement with no effect. Did you mean to break out of an outer loop? |
| SA4012 | Comparing a value against NaN even though no value is equal to NaN |
| SA4013 | Negating a boolean twice (!!b) is the same as writing b. This is either redundant, or a typo. |
| SA4014 | An if/else if chain has repeated conditions and no side-effects; if the condition didn't match the first time, it won't match the second time, either |
| SA4015 | Calling functions like math.Ceil on floats converted from integers doesn't do anything useful |
| SA4016 | Certain bitwise operations, such as x ^ 0, do not do anything useful |
| SA4017 | A pure function's return value is discarded, making the call pointless |
| SA5??? | Correctness issues |
| SA5000 | Assignment to nil map |
| SA5001 | Defering Close before checking for a possible error |
| SA5002 | The empty for loop (for {}) spins and can block the scheduler |
| SA5003 | Defers in infinite loops will never execute |
| SA5004 | for { select { ... with an empty default branch spins |
| SA5005 | The finalizer references the finalized object, preventing garbage collection |
| SA5006 | Slice index out of bounds |
| SA5007 | Infinite recursive call |
| SA9??? | Dubious code constructs that have a high probability of being wrong |
| SA9000 | Storing non-pointer values in sync.Pool allocates memory |
| SA9001 | defers in for range loops may not run when you expect them to |
| SA9002 | Using a non-octal os.FileMode that looks like it was meant to be in octal. |
staticcheck allows disabling some or all checks for certain files. The
-ignore flag takes a whitespace-separated list of
glob:check1,check2,... pairs. glob is a glob pattern matching
files in packages, and check1,check2,... are checks named by their
IDs.
For example, to ignore assignment to nil maps in all test files in the
os/exec package, you would write -ignore "os/exec/*_test.go:SA5000"
Additionally, the check IDs support globbing, too. Using a pattern
such as os/exec/*.gen.go:* would disable all checks in all
auto-generated files in the os/exec package.
Any whitespace can be used to separate rules, including newlines. This allows for a setup like the following:
$ cat stdlib.ignore
sync/*_test.go:SA2001
testing/benchmark.go:SA3001
runtime/string_test.go:SA4007
runtime/proc_test.go:SA5004
runtime/lfstack_test.go:SA4010
runtime/append_test.go:SA4010
errors/errors_test.go:SA4000
reflect/all_test.go:SA4000
$ staticcheck -ignore "$(cat stdlib.ignore)" std