Match prefix patterns for dependencies

internal/analysis/diagnostics.go

@@ -50,9 +50,18 @@ func checkSpacesInRecipes(mf *model.Makefile) []lsp.Diagnostic {
 
 // checkUndefinedTargetDeps warns about deps that reference undefined targets.
 func checkUndefinedTargetDeps(mf *model.Makefile) []lsp.Diagnostic {
-	targetSet := make(map[string]bool, len(mf.Targets))
-	for _, t := range mf.Targets {
-		targetSet[t.Name] = true
+	foundTarget := func(s string) bool {
+		for _, t := range mf.Targets {
+			if t.Name == s {
+				return true
+			}
+			prefix, suffix, hasPattern := strings.Cut(t.Name, "%")
+			if hasPattern && len(s) > len(prefix)+len(suffix) &&
+				strings.HasPrefix(s, prefix) && strings.HasSuffix(s, suffix) {
+				return true
+			}
+		}
+		return false
 	}
 
 	var diags []lsp.Diagnostic
@@ -61,7 +70,7 @@ func checkUndefinedTargetDeps(mf *model.Makefile) []lsp.Diagnostic {
 			if shouldSkipDepCheck(dep.Name) {
 				continue
 			}
-			if !targetSet[dep.Name] {
+			if !foundTarget(dep.Name) {
 				sev := lsp.SeverityWarning
 				diags = append(diags, lsp.Diagnostic{
 					Range:    dep.Range,

internal/analysis/diagnostics_test.go

@@ -63,6 +63,40 @@ func TestDiagnoseSkipsPatternDeps(t *testing.T) {
 	}
 }
 
+func TestDiagnoseFindsPatternDeps(t *testing.T) {
+	input := `all: src/main
+src/%: dest/%
+	$(CC) -o app $^
+`
+	mf := parser.Parse(testURI, input)
+	diags := Diagnose(mf)
+
+	for _, d := range diags {
+		if d.Severity != nil && *d.Severity == lsp.SeverityWarning {
+			assert.NotContains(t, d.Message, "undefined target")
+		}
+	}
+}
+
+func TestPatternRuleDoesNotSuppressUnrelatedWarnings(t *testing.T) {
+	input := `all: nonexistent
+	echo hi
+
+%.o: %.c
+	$(CC) -c $< -o $@
+`
+	mf := parser.Parse(testURI, input)
+	diags := Diagnose(mf)
+
+	var found bool
+	for _, d := range diags {
+		if d.Message == "undefined target: nonexistent" {
+			found = true
+		}
+	}
+	assert.True(t, found)
+}
+
 func TestDiagnoseSkipsFileDeps(t *testing.T) {
 	input := `all: main.o utils.o
 	$(CC) -o app $^

internal/parser/parser_test.go

@@ -198,6 +198,18 @@ func TestParseStaticPatternRule(t *testing.T) {
 	assert.Equal(t, "%.c", tgt.PrereqPattern)
 }
 
+func TestParsePrefixedPatternRule(t *testing.T) {
+	input := `src/%: dest/%
+	$(CC) -c $< -o $@
+`
+	m := Parse(testURI, input)
+
+	require.Len(t, m.Targets, 1)
+	tgt := m.Targets[0]
+	assert.True(t, tgt.IsPattern)
+	assert.Equal(t, "src/%", tgt.Name)
+}
+
 func TestParseOrderOnlyDeps(t *testing.T) {
 	input := `build: main.o utils.o | builddir
 	$(CC) -o $@ $^