Rules definitions

[mmorel-35]

The actual rules needs to clearly explicit to be easily understood and used by the users. This is a first draft that needs to be challenged to then enable the separation of concerns in the tool.

error-format

❌
fmt.Errorf("Simple message")
fmt.Sprintf("%s", err)
fmt.Sprintf("%v", err)

✅
errors.New("Simple message")
err.Error()

with:

• error-format.err-error option equivalent to err-error to use err.Error() even if it is only equivalent for non-nil errors

string-format

❌
fmt.Sprintf("%s", strVal)
fmt.Sprintf("format string %s", strVal)
fmt.Sprintf("%s format string", strVal)

✅
strVal
"format string " + strVal
strVal + "format string"

with

• string-format.concat option equivalent to strconcat to enable strings concatenation

bool-format

❌
fmt.Sprintf("%t", boolVal)

✅
strconv.FormatBool(boolBal)

hash-format

❌
fmt.Sprintf("%x", hash)

✅
hex.EncodeToString(hash)

integer-format

❌
fmt.Sprintf("%d", id)
fmt.Sprintf("%v", version)

✅
strconv.Itoa(id)
strconv.FormatUint(uint64(version), 10)

with

• integer-format.cast option equivalent to int-conversion to enable int or uint type cast

[alexandear]

Please remember that we have to maximize compatibility with existing rules:

  perfsprint:
    # Optimizes even if it requires an int or uint type cast.
    # Default: true
    int-conversion: false
    # Optimizes into `err.Error()` even if it is only equivalent for non-nil errors.
    # Default: false
    err-error: true
    # Optimizes `fmt.Errorf`.
    # Default: true
    errorf: false
    # Optimizes `fmt.Sprintf` with only one argument.
    # Default: true
    sprintf1: false
    # Optimizes into strings concatenation.
    # Default: true
    strconcat: false

https://github.com/golangci/golangci-lint/blob/e0e37c43762068149116bcd69b305c1ca05647ae/.golangci.reference.yml#L2190

Maybe it is better to add simply only one string-format rule to cover format cases for all types fmt.Sprintf("%t", boolVal), fmt.Sprintf("%x", hash), fmt.Sprintf("%d", id).

[catenacyber]

hash-format

Let's name it hex-format ?

[ccoVeille]

I was more likely to report them the way @alexandear suggested.

So hex would be reported as string-format

But, then the logic of having a way to configure what linter is enabled, it won't be easy.

Does it mean that it would be reported as string-format.hex

[ccoVeille]

Another distinct question, the related configuration would be something hex-conv ? The same way we have int-conv

I try to think about the configuration at the same time as the way we report them

[catenacyber]

I guess you need some rules like integer-format to have options like int-conversion

One thing to emphasize about current option is that there are some that do behavior changes :

• err-error : breaks behavior for nil errors
• sprintf1 : changes behavior (avoids panic) for string with user inputting %whatever in it