Add support for BAZELISK_NOJDK to Go Bazelisk (bazelbuild#531)

* TEST: test_BAZELISK_NOJDK

Passes for Python, fails for Go

* REFACTOR: introduce variable - flavor

* REFACTOR: introduce parameter - config

* Add BAZELISK_NOJDK support to Bazelisk Go

bazelisk_test.sh

@@ -267,6 +267,32 @@ function test_bazel_last_downstream_green() {
       (echo "FAIL: 'bazelisk version' of an unreleased binary must not print a build label."; exit 1)
 }
 
+function test_BAZELISK_NOJDK() {
+  setup
+
+  # Running the nojdk Bazel without a valid JAVA is expected to fail
+  set +e
+  BAZELISK_HOME="$BAZELISK_HOME" \
+      USE_BAZEL_VERSION="7.0.0" \
+      BAZELISK_NOJDK="1" \
+      bazelisk --noautodetect_server_javabase version 2>&1 | tee log
+  set -e
+
+  grep "FATAL: Could not find embedded or explicit server javabase, and --noautodetect_server_javabase is set." log || \
+      (echo "FAIL: nojdk Bazel should fail when no JDK is supplied."; exit 1)
+
+  # Theoretically there could be a cache collision in the Bazelisk cache between nojdk and regular Bazel.
+  #
+  # Ensure that isn't happening by running the regular Bazel right after nojdk Bazel, just in case. If there is a collision, it will fail.
+  BAZELISK_HOME="$BAZELISK_HOME" \
+      USE_BAZEL_VERSION="7.0.0" \
+      JAVA_HOME="does/not/exist" \
+      bazelisk --noautodetect_server_javabase version 2>&1 | tee log
+
+  grep "Build label: 7.0.0" log || \
+      (echo "FAIL: Expected to find 'Build label: 7.0.0' in the output of 'bazelisk version'"; exit 1)
+}
+
 function test_bazel_last_rc() {
   setup
 
@@ -491,6 +517,10 @@ echo "# test_bazel_last_downstream_green"
 test_bazel_last_downstream_green
 echo
 
+echo "# test_BAZELISK_NOJDK"
+test_BAZELISK_NOJDK
+echo
+
 if [[ $BAZELISK_VERSION == "GO" ]]; then
   echo "# test_bazel_version_go"
   test_bazel_version_go

core/core.go

@@ -346,7 +346,7 @@ func downloadBazel(bazelVersionString string, bazeliskHome string, repos *Reposi
 //	downloads/metadata/[fork-or-url]/bazel-[version-os-etc] is a text file containing a hex sha256 of the contents of the downloaded bazel file.
 //	downloads/sha256/[sha256]/bin/bazel[extension] contains the bazel with a particular sha256.
 func downloadBazelIfNecessary(version string, bazeliskHome string, bazelForkOrURLDirName string, repos *Repositories, config config.Config, downloader DownloadFunc) (string, error) {
-	pathSegment, err := platforms.DetermineBazelFilename(version, false)
+	pathSegment, err := platforms.DetermineBazelFilename(version, false, config)
 	if err != nil {
 		return "", fmt.Errorf("could not determine path segment to use for Bazel binary: %v", err)
 	}

core/repositories.go

@@ -227,7 +227,7 @@ func (r *Repositories) DownloadFromBaseURL(baseURL, version, destDir, destFile s
 		return "", fmt.Errorf("%s is not set", BaseURLEnv)
 	}
 
-	srcFile, err := platforms.DetermineBazelFilename(version, true)
+	srcFile, err := platforms.DetermineBazelFilename(version, true, config)
 	if err != nil {
 		return "", err
 	}

platforms/BUILD

@@ -6,6 +6,7 @@ go_library(
     importpath = "github.com/bazelbuild/bazelisk/platforms",
     visibility = ["//visibility:public"],
     deps = [
+        "//config:go_default_library",
         "//versions:go_default_library",
         "@com_github_hashicorp_go_version//:go_default_library",
     ],

platforms/platforms.go

@@ -6,6 +6,7 @@ import (
 	"log"
 	"runtime"
 
+	"github.com/bazelbuild/bazelisk/config"
 	"github.com/bazelbuild/bazelisk/versions"
 	semver "github.com/hashicorp/go-version"
 )
@@ -82,7 +83,15 @@ func DetermineOperatingSystem() (string, error) {
 }
 
 // DetermineBazelFilename returns the correct file name of a local Bazel binary.
-func DetermineBazelFilename(version string, includeSuffix bool) (string, error) {
+func DetermineBazelFilename(version string, includeSuffix bool, config config.Config) (string, error) {
+	flavor := "bazel"
+
+	bazeliskNojdk := config.Get("BAZELISK_NOJDK")
+
+	if len(bazeliskNojdk) != 0 && bazeliskNojdk != "0" {
+		flavor = "bazel_nojdk"
+	}
+
 	osName, err := DetermineOperatingSystem()
 	if err != nil {
 		return "", err
@@ -98,7 +107,7 @@ func DetermineBazelFilename(version string, includeSuffix bool) (string, error)
 		filenameSuffix = DetermineExecutableFilenameSuffix()
 	}
 
-	return fmt.Sprintf("bazel-%s-%s-%s%s", version, osName, machineName, filenameSuffix), nil
+	return fmt.Sprintf("%s-%s-%s-%s%s", flavor, version, osName, machineName, filenameSuffix), nil
 }
 
 // DarwinFallback Darwin arm64 was supported since 4.1.0, before 4.1.0, fall back to x86_64

repositories/gcs.go

@@ -139,7 +139,7 @@ type GcsListResponse struct {
 
 // DownloadRelease downloads the given Bazel release into the specified location and returns the absolute path.
 func (gcs *GCSRepo) DownloadRelease(version, destDir, destFile string, config config.Config) (string, error) {
-	srcFile, err := platforms.DetermineBazelFilename(version, true)
+	srcFile, err := platforms.DetermineBazelFilename(version, true, config)
 	if err != nil {
 		return "", err
 	}
@@ -235,7 +235,7 @@ func (gcs *GCSRepo) DownloadCandidate(version, destDir, destFile string, config
 		return "", fmt.Errorf("'%s' does not refer to a release candidate", version)
 	}
 
-	srcFile, err := platforms.DetermineBazelFilename(version, true)
+	srcFile, err := platforms.DetermineBazelFilename(version, true, config)
 	if err != nil {
 		return "", err
 	}
@@ -299,7 +299,7 @@ func (gcs *GCSRepo) GetRollingVersions(bazeliskHome string) ([]string, error) {
 
 // DownloadRolling downloads the given Bazel version into the specified location and returns the absolute path.
 func (gcs *GCSRepo) DownloadRolling(version, destDir, destFile string, config config.Config) (string, error) {
-	srcFile, err := platforms.DetermineBazelFilename(version, true)
+	srcFile, err := platforms.DetermineBazelFilename(version, true, config)
 	if err != nil {
 		return "", err
 	}

repositories/github.go

@@ -86,7 +86,7 @@ type gitHubRelease struct {
 
 // DownloadVersion downloads a Bazel binary for the given version and fork to the specified location and returns the absolute path.
 func (gh *GitHubRepo) DownloadVersion(fork, version, destDir, destFile string, config config.Config) (string, error) {
-	filename, err := platforms.DetermineBazelFilename(version, true)
+	filename, err := platforms.DetermineBazelFilename(version, true, config)
 	if err != nil {
 		return "", err
 	}