css: only show each :is warning once

evanw · Jul 19, 2023 · afd73d1 · afd73d1
1 parent 47d4f89
commit afd73d1
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Showing 4 changed files with 36 additions and 4 deletions.
diff --git a/internal/bundler_tests/bundler_css_test.go b/internal/bundler_tests/bundler_css_test.go
@@ -929,6 +929,9 @@ func TestCSSNestingOldBrowser(t *testing.T) {
 			"/two-type-selectors.css":   `a { .c b& { color: red; } }`,
 			"/two-parent-selectors.css": `a b { .c & { color: red; } }`,
 
+			// Make sure this only generates one warning (even though it generates ":is" three times)
+			"/only-one-warning.css": `.a, .b .c, .d { & > & { color: red; } }`,
+
 			"/nested-@layer.css":          `a { @layer base { color: red; } }`,
 			"/nested-@media.css":          `a { @media screen { color: red; } }`,
 			"/nested-ampersand-twice.css": `a { &, & { color: red; } }`,
@@ -970,6 +973,8 @@ func TestCSSNestingOldBrowser(t *testing.T) {
 			"/two-type-selectors.css",
 			"/two-parent-selectors.css",
 
+			"/only-one-warning.css",
+
 			"/nested-@layer.css",
 			"/nested-@media.css",
 			"/nested-ampersand-twice.css",
@@ -1012,7 +1017,9 @@ func TestCSSNestingOldBrowser(t *testing.T) {
 			UnsupportedCSSFeatures: compat.Nesting | compat.IsPseudoClass,
 			OriginalTargetEnv:      "chrome10",
 		},
-		expectedScanLog: `two-parent-selectors.css: WARNING: Transforming this CSS nesting syntax is not supported in the configured target environment (chrome10)
+		expectedScanLog: `only-one-warning.css: WARNING: Transforming this CSS nesting syntax is not supported in the configured target environment (chrome10)
+NOTE: The nesting transform for this case must generate an ":is(...)" but the configured target environment does not support the ":is" pseudo-class.
+two-parent-selectors.css: WARNING: Transforming this CSS nesting syntax is not supported in the configured target environment (chrome10)
 NOTE: The nesting transform for this case must generate an ":is(...)" but the configured target environment does not support the ":is" pseudo-class.
 two-type-selectors.css: WARNING: Transforming this CSS nesting syntax is not supported in the configured target environment (chrome10)
 NOTE: The nesting transform for this case must generate an ":is(...)" but the configured target environment does not support the ":is" pseudo-class.

diff --git a/internal/bundler_tests/snapshots/snapshots_css.txt b/internal/bundler_tests/snapshots/snapshots_css.txt
@@ -192,6 +192,20 @@ TestCSSNestingOldBrowser
   color: red;
 }
 
+---------- /out/only-one-warning.css ----------
+/* only-one-warning.css */
+.a > .a,
+.a > :is(.b .c),
+.a > .d,
+.b .c > .a,
+.b .c > :is(.b .c),
+.b .c > .d,
+.d > .a,
+.d > :is(.b .c),
+.d > .d {
+  color: red;
+}
+
 ---------- /out/nested-@layer.css ----------
 /* nested-@layer.css */
 @layer base {

diff --git a/internal/css_parser/css_nesting.go b/internal/css_parser/css_nesting.go
@@ -374,7 +374,7 @@ func (p *parser) substituteAmpersandsInCompoundSelector(
 		} else {
 			// ".foo .bar { :hover & {} }" => ":hover :is(.foo .bar) {}"
 			// ".foo .bar { > &:hover {} }" => ".foo .bar > :is(.foo .bar):hover {}"
-			p.reportNestingWithGeneratedPseudoClassIs(logger.Range{Loc: nestingSelectorLoc, Len: 1})
+			p.reportNestingWithGeneratedPseudoClassIs(nestingSelectorLoc)
 			single = css_ast.CompoundSelector{
 				SubclassSelectors: []css_ast.SubclassSelector{{
 					Loc: nestingSelectorLoc,
@@ -391,7 +391,7 @@ func (p *parser) substituteAmpersandsInCompoundSelector(
 		// Insert the type selector
 		if single.TypeSelector != nil {
 			if sel.TypeSelector != nil {
-				p.reportNestingWithGeneratedPseudoClassIs(logger.Range{Loc: nestingSelectorLoc, Len: 1})
+				p.reportNestingWithGeneratedPseudoClassIs(nestingSelectorLoc)
 				subclassSelectorPrefix = append(subclassSelectorPrefix, css_ast.SubclassSelector{
 					Loc: sel.TypeSelector.FirstLoc(),
 					Data: &css_ast.SSPseudoClassWithSelectorList{
@@ -465,12 +465,22 @@ func (p *parser) multipleComplexSelectorsToSingleComplexSelector(selectors []css
 	}
 }
 
-func (p *parser) reportNestingWithGeneratedPseudoClassIs(r logger.Range) {
+func (p *parser) reportNestingWithGeneratedPseudoClassIs(nestingSelectorLoc logger.Loc) {
 	if p.options.unsupportedCSSFeatures.Has(compat.IsPseudoClass) {
+		_, didWarn := p.nestingWarnings[nestingSelectorLoc]
+		if didWarn {
+			// Only warn at each location once
+			return
+		}
+		if p.nestingWarnings == nil {
+			p.nestingWarnings = make(map[logger.Loc]struct{})
+		}
+		p.nestingWarnings[nestingSelectorLoc] = struct{}{}
 		text := "Transforming this CSS nesting syntax is not supported in the configured target environment"
 		if p.options.originalTargetEnv != "" {
 			text = fmt.Sprintf("%s (%s)", text, p.options.originalTargetEnv)
 		}
+		r := logger.Range{Loc: nestingSelectorLoc, Len: 1}
 		p.log.AddIDWithNotes(logger.MsgID_CSS_UnsupportedCSSNesting, logger.Warning, &p.tracker, r, text, []logger.MsgData{{
 			Text: "The nesting transform for this case must generate an \":is(...)\" but the configured target environment does not support the \":is\" pseudo-class."}})
 	}

diff --git a/internal/css_parser/css_parser.go b/internal/css_parser/css_parser.go
@@ -26,6 +26,7 @@ type parser struct {
 	symbols            []ast.Symbol
 	localSymbolMap     map[string]ast.Ref
 	globalSymbolMap    map[string]ast.Ref
+	nestingWarnings    map[logger.Loc]struct{}
 	tracker            logger.LineColumnTracker
 	index              int
 	end                int