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File: [cvs.NetBSD.org] / pkgsrc / pkgtools / pkglint / files / mkcondchecker.go (download)

Revision 1.1, Sun Dec 8 00:06:38 2019 UTC (2 months, 2 weeks ago) by rillig
Branch: MAIN

pkgtools/pkglint: update to 19.3.14

Changes since 19.3.13:

When pkglint suggests to replace !empty(VARNAME:Mfixed) with ${VARNAME}
== fixed, the exact suggested expression is now part of the diagnostic.
The check and the autofix have been improved. They now apply only to the
last modifier in the whole chain, everything else was a bug in pkglint.

Pkglint now knows the scope of variables better than before. It knows
the difference between variables from <sys.mk> like MACHINE_ARCH, which
are always in scope, and those from mk/defaults/mk.conf, which only come
into scope later, after bsd.prefs.mk has been included. It warns when
variables are used too early, for example in .if conditions.

The pathnames in ALTERNATIVES files are now checked for absolute
pathnames. This mistake doesn't happen in practice, but the code for
converting the different path types internally made it necessary to add
these checks. At least this prevents typos.

The special check for obsolete licenses has been removed since their
license files have been removed and that is checked as well.

Variables named *_AWK may be appended to.

The variables _PKG_SILENT and _PKG_DEBUG are no longer deprecated, they
are obsolete now. They are not used in main pkgsrc and pkgsrc-wip
anymore.

When a package sets a default value for a user-settable variable (which
is something that should not happen anyway), it should .include
bsd.prefs.mk before, in order to not accidentally overwrite the
user-specified value.

Variable modifiers of the form :from=to are now parsed like in bmake.
They are greedy and eat up any following colons as well. This means that
${VAR:.c=.o:Q} replaces source.c with source.o:Q, instead of quoting it.
Pkglint now warns about such cases.

The handling of relative paths in diagnostics is now consistent. All
paths that are part of a diagnostic are relative to the line that issues
the diagnostic.

Fatal errors are no longer suppressed in --autofix mode.

Plus lots of refactoring, to prevent accidental mixing of incompatible
relative paths.

package pkglint

import "netbsd.org/pkglint/textproc"

// MkCondChecker checks conditions in Makefiles.
// These conditions occur in .if and .elif clauses, as well as the
// :? modifier.
type MkCondChecker struct {
	MkLine  *MkLine
	MkLines *MkLines
}

func NewMkCondChecker(mkLine *MkLine, mkLines *MkLines) *MkCondChecker {
	return &MkCondChecker{MkLine: mkLine, MkLines: mkLines}
}

func (ck *MkCondChecker) checkDirectiveCond() {
	mkline := ck.MkLine
	if trace.Tracing {
		defer trace.Call1(mkline.Args())()
	}

	p := NewMkParser(nil, mkline.Args()) // No emitWarnings here, see the code below.
	cond := p.MkCond()
	if !p.EOF() {
		mkline.Warnf("Invalid condition, unrecognized part: %q.", p.Rest())
		return
	}

	checkVarUse := func(varuse *MkVarUse) {
		var vartype *Vartype // TODO: Insert a better type guess here.
		vuc := VarUseContext{vartype, VucLoadTime, VucQuotPlain, false}
		NewMkVarUseChecker(varuse, ck.MkLines, mkline).Check(&vuc)
	}

	// Skip subconditions that have already been handled as part of the !(...).
	done := make(map[interface{}]bool)

	checkNotEmpty := func(not *MkCond) {
		empty := not.Empty
		if empty != nil {
			ck.checkDirectiveCondEmpty(empty, true, true)
			done[empty] = true
		}

		if not.Term != nil && not.Term.Var != nil {
			varUse := not.Term.Var
			ck.checkDirectiveCondEmpty(varUse, false, false)
			done[varUse] = true
		}
	}

	checkEmpty := func(empty *MkVarUse) {
		if !done[empty] {
			ck.checkDirectiveCondEmpty(empty, true, false)
		}
	}

	checkVar := func(varUse *MkVarUse) {
		if !done[varUse] {
			ck.checkDirectiveCondEmpty(varUse, false, true)
		}
	}

	cond.Walk(&MkCondCallback{
		Not:     checkNotEmpty,
		Empty:   checkEmpty,
		Var:     checkVar,
		Compare: ck.checkDirectiveCondCompare,
		VarUse:  checkVarUse})
}

// checkDirectiveCondEmpty checks a condition of the form empty(VAR),
// empty(VAR:Mpattern) or ${VAR:Mpattern} in an .if directive.
func (ck *MkCondChecker) checkDirectiveCondEmpty(varuse *MkVarUse, fromEmpty bool, neg bool) {
	ck.checkDirectiveCondEmptyExpr(varuse)
	ck.checkDirectiveCondEmptyType(varuse)
	ck.simplifyCondition(varuse, fromEmpty, neg)
}

func (ck *MkCondChecker) checkDirectiveCondEmptyExpr(varuse *MkVarUse) {
	if !matches(varuse.varname, `^\$.*:[MN]`) {
		return
	}

	ck.MkLine.Warnf("The empty() function takes a variable name as parameter, " +
		"not a variable expression.")
	ck.MkLine.Explain(
		"Instead of empty(${VARNAME:Mpattern}), you should write either of the following:",
		"",
		"\tempty(VARNAME:Mpattern)",
		"\t${VARNAME:Mpattern} == \"\"",
		"",
		"Instead of !empty(${VARNAME:Mpattern}), you should write either of the following:",
		"",
		"\t!empty(VARNAME:Mpattern)",
		"\t${VARNAME:Mpattern}")
}

func (ck *MkCondChecker) checkDirectiveCondEmptyType(varuse *MkVarUse) {
	for _, modifier := range varuse.modifiers {
		ok, _, pattern, _ := modifier.MatchMatch()
		if ok {
			mkLineChecker := NewMkLineChecker(ck.MkLines, ck.MkLine)
			mkLineChecker.checkVartype(varuse.varname, opUseMatch, pattern, "")
			continue
		}

		switch modifier.Text {
		default:
			return
		case "O", "u":
		}
	}
}

// mkCondStringLiteralUnquoted contains a safe subset of the characters
// that may be used without surrounding quotes in a comparison such as
// ${PKGPATH} == category/package.
var mkCondStringLiteralUnquoted = textproc.NewByteSet("+---./0-9@A-Z_a-z")

// mkCondModifierPatternLiteral contains a safe subset of the characters
// that are interpreted literally in the :M and :N modifiers.
var mkCondModifierPatternLiteral = textproc.NewByteSet("+---./0-9<=>@A-Z_a-z")

// simplifyCondition replaces an unnecessarily complex condition with
// a simpler condition that's still equivalent.
//
// * fromEmpty is true for the form empty(VAR...), and false for ${VAR...}.
//
// * neg is true for the form !empty(VAR...), and false for empty(VAR...).
// It also applies to the ${VAR} form.
func (ck *MkCondChecker) simplifyCondition(varuse *MkVarUse, fromEmpty bool, neg bool) {
	varname := varuse.varname
	mods := varuse.modifiers
	modifiers := mods

	n := len(modifiers)
	if n == 0 {
		return
	}
	modsExceptLast := NewMkVarUse("", mods[:n-1]...).Mod()
	vartype := G.Pkgsrc.VariableType(ck.MkLines, varname)

	isDefined := func() bool {
		if vartype.IsAlwaysInScope() && vartype.IsDefinedIfInScope() {
			return true
		}

		if ck.MkLines.vars.IsDefined(varname) {
			return true
		}

		return ck.MkLines.Tools.SeenPrefs &&
			vartype.Union().Contains(aclpUseLoadtime) &&
			vartype.IsDefinedIfInScope()
	}

	// replace constructs the state before and after the autofix.
	// The before state is constructed to ensure that only very simple
	// patterns get replaced automatically.
	//
	// Before putting any cases involving special characters into
	// production, there need to be more tests for the edge cases.
	replace := func(positive bool, pattern string) (bool, string, string) {
		defined := isDefined()
		if !defined && !positive {
			// TODO: This is a double negation, maybe even triple.
			//  There is an :N pattern, and the variable may be undefined.
			//  If it is indeed undefined, should the whole condition
			//  evaluate to true or false?
			//  The cases to be distinguished are: undefined, empty, filled.

			// For now, be conservative and don't suggest anything wrong.
			return false, "", ""
		}
		uMod := condStr(!defined && !varuse.HasModifier("U"), ":U", "")

		op := condStr(neg == positive, "==", "!=")

		from := sprintf("%s%s%s%s%s%s%s",
			condStr(neg != fromEmpty, "", "!"),
			condStr(fromEmpty, "empty(", "${"),
			varname,
			modsExceptLast,
			condStr(positive, ":M", ":N"),
			pattern,
			condStr(fromEmpty, ")", "}"))

		needsQuotes := textproc.NewLexer(pattern).NextBytesSet(mkCondStringLiteralUnquoted) != pattern ||
			matches(pattern, `^\d+\.?\d*$`)
		quote := condStr(needsQuotes, "\"", "")

		to := sprintf(
			"${%s%s%s} %s %s%s%s",
			varname, uMod, modsExceptLast, op, quote, pattern, quote)

		return true, from, to
	}

	modifier := modifiers[n-1]
	ok, positive, pattern, exact := modifier.MatchMatch()
	if !ok || !positive && n != 1 {
		return
	}

	switch {
	case !exact,
		vartype == nil,
		vartype.IsList(),
		textproc.NewLexer(pattern).NextBytesSet(mkCondModifierPatternLiteral) != pattern:
		return
	}

	ok, from, to := replace(positive, pattern)
	if !ok {
		return
	}

	fix := ck.MkLine.Autofix()
	fix.Notef("%s should be compared using \"%s\" instead of matching against %q.",
		varname, to, ":"+modifier.Text)
	fix.Explain(
		"This variable has a single value, not a list of values.",
		"Therefore it feels strange to apply list operators like :M and :N onto it.",
		"A more direct approach is to use the == and != operators.",
		"",
		"An entirely different case is when the pattern contains",
		"wildcards like *, ?, [].",
		"In such a case, using the :M or :N modifiers is useful and preferred.")
	fix.Replace(from, to)
	fix.Apply()
}

func (ck *MkCondChecker) checkDirectiveCondCompare(left *MkCondTerm, op string, right *MkCondTerm) {
	switch {
	case left.Var != nil && right.Var == nil && right.Num == "":
		ck.checkDirectiveCondCompareVarStr(left.Var, op, right.Str)
	}
}

func (ck *MkCondChecker) checkDirectiveCondCompareVarStr(varuse *MkVarUse, op string, str string) {
	varname := varuse.varname
	varmods := varuse.modifiers
	switch len(varmods) {
	case 0:
		ck.checkCompareVarStr(varname, op, str)

	case 1:
		if m, _, pattern, _ := varmods[0].MatchMatch(); m {
			mkLineChecker := NewMkLineChecker(ck.MkLines, ck.MkLine)
			mkLineChecker.checkVartype(varname, opUseMatch, pattern, "")

			// After applying the :M or :N modifier, every expression may end up empty,
			// regardless of its data type. Therefore there's no point in type-checking that case.
			if str != "" {
				mkLineChecker.checkVartype(varname, opUseCompare, str, "")
			}
		}

	default:
		// This case covers ${VAR:Mfilter:O:u} or similar uses in conditions.
		// To check these properly, pkglint first needs to know the most common
		// modifiers and how they interact.
		// As of March 2019, the modifiers are not modeled.
		// The following tracing statement makes it easy to discover these cases,
		// in order to decide whether checking them is worthwhile.
		if trace.Tracing {
			trace.Stepf("checkCompareVarStr ${%s%s} %s %s",
				varuse.varname, varuse.Mod(), op, str)
		}
	}
}

func (ck *MkCondChecker) checkCompareVarStr(varname, op, value string) {
	mkLineChecker := NewMkLineChecker(ck.MkLines, ck.MkLine)
	mkLineChecker.checkVartype(varname, opUseCompare, value, "")

	if varname == "PKGSRC_COMPILER" {
		ck.checkCompareVarStrCompiler(op, value)
	}
}

func (ck *MkCondChecker) checkCompareVarStrCompiler(op string, value string) {
	if !matches(value, `^\w+$`) {
		return
	}

	// It would be nice if original text of the whole comparison expression
	// were available at this point, to avoid guessing how much whitespace
	// the package author really used.

	matchOp := condStr(op == "==", "M", "N")

	fix := ck.MkLine.Autofix()
	fix.Errorf("Use ${PKGSRC_COMPILER:%s%s} instead of the %s operator.", matchOp, value, op)
	fix.Explain(
		"The PKGSRC_COMPILER can be a list of chained compilers, e.g. \"ccache distcc clang\".",
		"Therefore, comparing it using == or != leads to wrong results in these cases.")
	fix.Replace("${PKGSRC_COMPILER} "+op+" "+value, "${PKGSRC_COMPILER:"+matchOp+value+"}")
	fix.Replace("${PKGSRC_COMPILER} "+op+" \""+value+"\"", "${PKGSRC_COMPILER:"+matchOp+value+"}")
	fix.Apply()
}