fix(homebrew): avoid redundant formula version

.github/homebrew/bits.rb.erb

@@ -8,8 +8,6 @@
 class Bits < Formula
   desc "Datadog Assistant in your terminal"
   homepage "https://github.com/datadog-labs/bits-cli"
-  # Shipped bits binaries read this line to offer updates; keep exactly one.
-  version "<%= values.fetch("version") %>"
   license "Apache-2.0"
 
   on_macos do

internal/update/homebrew.go

@@ -124,16 +124,24 @@ func detectBackend(executable string) (backend, error) {
 	return h, nil
 }
 
-// Read only the explicit version declaration in our generated formula. This is
-// deliberately not a Ruby parser; unexpected formats fail the check silently.
-var formulaVersion = regexp.MustCompile(`(?m)^[\t ]*version[\t ]+"([^"\r\n]+)"[\t ]*\r?$`)
+// Read the version from the release download URLs in our generated formula.
+// Homebrew infers its formula version from these URLs, so avoid duplicating it
+// in an explicit version stanza. This is deliberately not a Ruby parser;
+// unexpected formats fail the check silently.
+var formulaReleaseVersion = regexp.MustCompile(`(?m)^[\t ]*url[\t ]+"[^"\r\n]*/releases/download/v([^/"\r\n]+)/[^"\r\n]+"[\t ]*\r?$`)
 
 func homebrewVersion(raw []byte) (string, error) {
-	matches := formulaVersion.FindAllSubmatch(raw, -1)
-	if len(matches) != 1 {
-		return "", fmt.Errorf("%w: expected one explicit Homebrew version", errInvalidVersion)
+	matches := formulaReleaseVersion.FindAllSubmatch(raw, -1)
+	if len(matches) == 0 {
+		return "", fmt.Errorf("%w: expected one version across Homebrew release URLs", errInvalidVersion)
 	}
-	latest := "v" + string(matches[0][1])
+	version := string(matches[0][1])
+	for _, match := range matches[1:] {
+		if string(match[1]) != version {
+			return "", fmt.Errorf("%w: mismatched versions across Homebrew release URLs", errInvalidVersion)
+		}
+	}
+	latest := "v" + version
 	if !semver.IsValid(latest) {
 		return "", fmt.Errorf("%w: Homebrew version %q", errInvalidVersion, latest)
 	}

internal/update/update_test.go

@@ -223,7 +223,7 @@ func TestHomebrewFetch(t *testing.T) {
 		body, want string
 		invalid    bool
 	}{
-		{"success", 200, `  version "1.3.0"`, "v1.3.0", false},
+		{"success", 200, `  url "https://github.com/datadog-labs/bits-cli/releases/download/v1.3.0/bits_1.3.0_linux_amd64.tar.gz"`, "v1.3.0", false},
 		{"server", 500, "", "", false},
 		{"missing", 404, "", "", false},
 		{"redirect", 302, "", "", false},
@@ -394,13 +394,12 @@ func TestHomebrewUpgrade(t *testing.T) {
 
 func TestHomebrewVersion(t *testing.T) {
 	for _, tc := range []struct{ name, formula, want string }{
-		{"generated format", "class Bits < Formula\n  version \"1.2.3\"\n  on_macos do\n    url \"https://example.com/v9.9.9/bits.tar.gz\"\n  end\nend\n", "v1.2.3"},
-		{"windows newlines", "  version \"1.2.3\"\r\n", "v1.2.3"},
+		{"generated format", "class Bits < Formula\n  on_macos do\n    url \"https://github.com/datadog-labs/bits-cli/releases/download/v1.2.3/bits_1.2.3_darwin_arm64.tar.gz\"\n    url \"https://github.com/datadog-labs/bits-cli/releases/download/v1.2.3/bits_1.2.3_darwin_amd64.tar.gz\"\n  end\nend\n", "v1.2.3"},
+		{"windows newlines", "  url \"https://github.com/datadog-labs/bits-cli/releases/download/v1.2.3/bits_1.2.3_linux_amd64.tar.gz\"\r\n", "v1.2.3"},
 		{"missing", "class Bits < Formula\nend\n", ""},
-		{"comment", "  # version \"1.2.3\"\n", ""},
-		{"duplicate", "  version \"1.2.3\"\n  version \"1.2.4\"\n", ""},
-		{"expression", "  version ENV.fetch(\"VERSION\")\n", ""},
-		{"interpolation", "  version \"#{version}\"\n", ""},
+		{"comment", "  # url \"https://github.com/datadog-labs/bits-cli/releases/download/v1.2.3/bits_1.2.3_darwin_arm64.tar.gz\"\n", ""},
+		{"mismatched release URLs", "  url \"https://github.com/datadog-labs/bits-cli/releases/download/v1.2.3/bits_1.2.3_darwin_arm64.tar.gz\"\n  url \"https://github.com/datadog-labs/bits-cli/releases/download/v1.2.4/bits_1.2.4_linux_amd64.tar.gz\"\n", ""},
+		{"invalid version", "  url \"https://github.com/datadog-labs/bits-cli/releases/download/vnot-a-version/bits.tar.gz\"\n", ""},
 	} {
 		t.Run(tc.name, func(t *testing.T) {
 			got, err := homebrewVersion([]byte(tc.formula))

scripts/ciworkflow_test.go

@@ -290,8 +290,8 @@ func TestHomebrewTemplate(t *testing.T) {
 	if err != nil {
 		t.Fatalf("render formula: %v\n%s", err, formula)
 	}
-	if got := strings.Count(string(formula), "\n  version \"1.2.3\"\n"); got != 1 {
-		t.Fatalf("expected one explicit version declaration, got %d", got)
+	if strings.Contains(string(formula), "\n  version ") {
+		t.Fatal("formula should let Homebrew infer the version from its release URLs")
 	}
 	for _, platform := range platforms {
 		url := `url "https://github.com/datadog-labs/bits-cli/releases/download/v1.2.3/bits_1.2.3_` + platform + `.tar.gz"`

scripts/try-update.sh

@@ -64,7 +64,7 @@ chmod +x "$PREFIX/bin/brew"
 
 # Start without a cache so the first launch performs the real check.
 rm -f "$STATE"
-echo "--- serving $URL ($(grep -m1 '^ *version ' "$PREFIX/www/Formula/bits.rb" | xargs))"
+echo "--- serving $URL ($(grep -m1 'releases/download/v' "$PREFIX/www/Formula/bits.rb" | sed -E 's|.*releases/download/(v[^/]+)/.*|\1|'))"
 
 while true; do
     echo "--- launching $("$PREFIX/bin/bits" --version)"