weave-scope/lint

#!/bin/bash
# This scipt lints files for common errors.
#
# For go files, it runs gofmt and go vet, and optionally golint and
# gocyclo, if they are installed.
#
# For shell files, it runs shfmt. If you don't have that installed, you can get
# it with:
#   go get -u github.com/mvdan/sh/cmd/shfmt
#
# With no arguments, it lints the current files staged
# for git commit.  Or you can pass it explicit filenames
# (or directories) and it will lint them.
#
# To use this script automatically, run:
#   ln -s ../../bin/lint .git/hooks/pre-commit

set -e

IGNORE_LINT_COMMENT=
IGNORE_TEST_PACKAGES=
IGNORE_SPELLINGS=
while true; do
    case "$1" in
        -nocomment)
            IGNORE_LINT_COMMENT=1
            shift 1
            ;;
        -notestpackage)
            IGNORE_TEST_PACKAGES=1
            shift 1
            ;;
        -ignorespelling)
            IGNORE_SPELLINGS="$2,$IGNORE_SPELLINGS"
            shift 2
            ;;
        *)
            break
            ;;
    esac
done

spell_check() {
    filename="$1"
    local lint_result=0

    # we don't want to spell check tar balls, binaries, Makefile and json files
    if file "$filename" | grep executable >/dev/null 2>&1; then
        return $lint_result
    fi
    if [[ $filename == *".tar" || $filename == *".gz" || $filename == *".json" || $(basename "$filename") == "Makefile" ]]; then
        return $lint_result
    fi

    # misspell is completely optional.  If you don't like it
    # don't have it installed.
    if ! type misspell >/dev/null 2>&1; then
        return $lint_result
    fi

    if ! misspell -error -i "$IGNORE_SPELLINGS" "${filename}"; then
        lint_result=1
    fi

    return $lint_result
}

test_mismatch() {
    filename="$1"
    package=$(grep '^package ' "$filename" | awk '{print $2}')
    local lint_result=0

    if [[ $package == "main" ]]; then
        return # in package main, all bets are off
    fi

    if [[ $filename == *"_internal_test.go" ]]; then
        if [[ $package == *"_test" ]]; then
            lint_result=1
            echo "${filename}: should not be part of a _test package"
        fi
    else
        if [[ ! $package == *"_test" ]]; then
            lint_result=1
            echo "${filename}: should be part of a _test package"
        fi
    fi

    return $lint_result
}

lint_go() {
    filename="$1"
    local lint_result=0

    if [ -n "$(gofmt -s -l "${filename}")" ]; then
        lint_result=1
        echo "${filename}: run gofmt -s -w ${filename}"
    fi

    go tool vet "${filename}" || lint_result=$?

    # golint is completely optional.  If you don't like it
    # don't have it installed.
    if type golint >/dev/null 2>&1; then
        # golint doesn't set an exit code it seems
        if [ -z "$IGNORE_LINT_COMMENT" ]; then
            lintoutput=$(golint "${filename}")
        else
            lintoutput=$(golint "${filename}" | grep -vE 'comment|dot imports|ALL_CAPS')
        fi
        if [ -n "$lintoutput" ]; then
            lint_result=1
            echo "$lintoutput"
        fi
    fi

    # gocyclo is completely optional.  If you don't like it
    # don't have it installed.  Also never blocks a commit,
    # it just warns.
    if type gocyclo >/dev/null 2>&1; then
        gocyclo -over 25 "${filename}" | while read -r line; do
            echo "${filename}": higher than 25 cyclomatic complexity - "${line}"
        done
    fi

    return $lint_result
}

lint_sh() {
    filename="$1"
    local lint_result=0

    if [ -n "$(diff <(shfmt -i 4 "${filename}") "${filename}")" ]; then
        lint_result=1
        echo "${filename}: run shfmt -i 4 -w ${filename}"
    fi

    # the shellcheck is completely optional.  If you don't like it
    # don't have it installed.
    if type shellcheck >/dev/null 2>&1; then
        shellcheck "${filename}"
        lint_result=$?
    fi

    return $lint_result
}

lint() {
    filename="$1"
    ext="${filename##*\.}"
    local lint_result=0

    # Don't lint deleted files
    if [ ! -f "$filename" ]; then
        return
    fi

    # Don't lint static.go
    case "$(basename "${filename}")" in
        static.go) return ;;
        coverage.html) return ;;
    esac

    if [[ "$(file --mime-type "${filename}" | awk '{print $2}')" = "text/x-shellscript" ]]; then
        ext="sh"
    fi

    case "$ext" in
        go) lint_go "${filename}" || lint_result=1 ;;
        sh) lint_sh "${filename}" || lint_result=1 ;;
    esac

    if [ -z "$IGNORE_TEST_PACKAGES" ]; then
        if [[ "$filename" == *"_test.go" ]]; then
            test_mismatch "${filename}" || lint_result=1
        fi
    fi

    spell_check "${filename}" || lint_result=1

    return $lint_result
}

lint_files() {
    local lint_result=0
    while read -r filename; do
        lint "${filename}" || lint_result=1
    done
    exit $lint_result
}

list_files() {
    if [ $# -gt 0 ]; then
        git ls-files --exclude-standard | grep -vE '(^|/)vendor/'
    else
        git diff --cached --name-only
    fi
}

list_files "$@" | lint_files