Use the local JDK as the default target javabase

and continue to use the embedded JDK as the default host_javabase.

PiperOrigin-RevId: 196471714

8 files changed, 41 insertions, 42 deletions

diff --git a/src/main/cpp/blaze.cc b/src/main/cpp/blaze.cc
index 6c9aea3895..331c4c212b 100644
--- a/src/main/cpp/blaze.cc
+++ b/src/main/cpp/blaze.cc
@@ -505,6 +505,7 @@ static vector<string> GetArgumentArray(
                    blaze::ConvertPath(globals->options->output_base));
   result.push_back("--workspace_directory=" +
                    blaze::ConvertPath(globals->workspace));
+  result.push_back("--default_system_javabase=" + GetSystemJavabase());
 
   if (!globals->options->server_jvm_out.empty()) {
     result.push_back("--server_jvm_out=" + globals->options->server_jvm_out);
diff --git a/src/main/cpp/blaze_util_darwin.cc b/src/main/cpp/blaze_util_darwin.cc
index 4bc3990eab..c925e2e3fb 100644
--- a/src/main/cpp/blaze_util_darwin.cc
+++ b/src/main/cpp/blaze_util_darwin.cc
@@ -159,7 +159,7 @@ bool IsSharedLibrary(const string &filename) {
   return blaze_util::ends_with(filename, ".dylib");
 }
 
-string GetDefaultHostJavabase() {
+string GetSystemJavabase() {
   string java_home = GetEnv("JAVA_HOME");
   if (!java_home.empty()) {
     return java_home;
@@ -167,23 +167,19 @@ string GetDefaultHostJavabase() {
 
   FILE *output = popen("/usr/libexec/java_home -v 1.7+", "r");
   if (output == NULL) {
-    BAZEL_DIE(blaze_exit_code::LOCAL_ENVIRONMENTAL_ERROR)
-        << "Could not run /usr/libexec/java_home: " << GetLastErrorString();
+    return "";
   }
 
   char buf[512];
   char *result = fgets(buf, sizeof(buf), output);
   pclose(output);
   if (result == NULL) {
-    BAZEL_DIE(blaze_exit_code::LOCAL_ENVIRONMENTAL_ERROR)
-        << "No output from /usr/libexec/java_home";
+    return "";
   }
 
   string javabase = buf;
   if (javabase.empty()) {
-    BAZEL_DIE(blaze_exit_code::LOCAL_ENVIRONMENTAL_ERROR)
-        << "Empty output from /usr/libexec/java_home - install a JDK, or "
-           "install a JRE and point your JAVA_HOME to it";
+    return "";
   }
 
   // The output ends with a \n, trim it off.
diff --git a/src/main/cpp/blaze_util_freebsd.cc b/src/main/cpp/blaze_util_freebsd.cc
index 4b27b4287d..0d196827d8 100644
--- a/src/main/cpp/blaze_util_freebsd.cc
+++ b/src/main/cpp/blaze_util_freebsd.cc
@@ -143,7 +143,7 @@ bool IsSharedLibrary(const string &filename) {
   return blaze_util::ends_with(filename, ".so");
 }
 
-string GetDefaultHostJavabase() {
+string GetSystemJavabase() {
   // if JAVA_HOME is defined, then use it as default.
   string javahome = GetEnv("JAVA_HOME");
   return !javahome.empty() ? javahome : "/usr/local/openjdk8";
diff --git a/src/main/cpp/blaze_util_linux.cc b/src/main/cpp/blaze_util_linux.cc
index ba0320d1c2..4f01ba833b 100644
--- a/src/main/cpp/blaze_util_linux.cc
+++ b/src/main/cpp/blaze_util_linux.cc
@@ -146,8 +146,7 @@ bool IsSharedLibrary(const string &filename) {
 static string Which(const string &executable) {
   string path(GetEnv("PATH"));
   if (path.empty()) {
-    BAZEL_DIE(blaze_exit_code::LOCAL_ENVIRONMENTAL_ERROR)
-        << "Could not get PATH to find " << executable;
+    return "";
   }
 
   vector<string> pieces = blaze_util::Split(path, ':');
@@ -167,7 +166,7 @@ static string Which(const string &executable) {
   return "";
 }
 
-string GetDefaultHostJavabase() {
+string GetSystemJavabase() {
   // if JAVA_HOME is defined, then use it as default.
   string javahome = GetEnv("JAVA_HOME");
   if (!javahome.empty()) {
@@ -177,15 +176,13 @@ string GetDefaultHostJavabase() {
   // which javac
   string javac_dir = Which("javac");
   if (javac_dir.empty()) {
-    BAZEL_DIE(blaze_exit_code::LOCAL_ENVIRONMENTAL_ERROR)
-        << "Could not find javac";
+    return "";
   }
 
   // Resolve all symlinks.
   char resolved_path[PATH_MAX];
   if (realpath(javac_dir.c_str(), resolved_path) == NULL) {
-    BAZEL_DIE(blaze_exit_code::LOCAL_ENVIRONMENTAL_ERROR)
-        << "Could not resolve javac directory: " << GetLastErrorString();
+    return "";
   }
   javac_dir = resolved_path;
 
diff --git a/src/main/cpp/blaze_util_platform.h b/src/main/cpp/blaze_util_platform.h
index 50ac21933f..6de5eb154a 100644
--- a/src/main/cpp/blaze_util_platform.h
+++ b/src/main/cpp/blaze_util_platform.h
@@ -84,9 +84,10 @@ std::string GetProcessCWD(int pid);
 
 bool IsSharedLibrary(const std::string& filename);
 
-// Return the default path to the JDK used to run Blaze itself
-// (must be an absolute directory).
-std::string GetDefaultHostJavabase();
+// Returns the absolute path to the user's local JDK install, to be used as
+// the default target javabase and as a fall-back host_javabase. This is not
+// the embedded JDK.
+std::string GetSystemJavabase();
 
 // Return the path to the JVM binary relative to a javabase, e.g. "bin/java".
 std::string GetJavaBinaryUnderJavabase();
diff --git a/src/main/cpp/blaze_util_windows.cc b/src/main/cpp/blaze_util_windows.cc
index efd0d72c59..565e8876c2 100644
--- a/src/main/cpp/blaze_util_windows.cc
+++ b/src/main/cpp/blaze_util_windows.cc
@@ -250,11 +250,10 @@ bool IsSharedLibrary(const string &filename) {
   return blaze_util::ends_with(filename, ".dll");
 }
 
-string GetDefaultHostJavabase() {
+string GetSystemJavabase() {
   string javahome(GetEnv("JAVA_HOME"));
   if (javahome.empty()) {
-    BAZEL_DIE(blaze_exit_code::LOCAL_ENVIRONMENTAL_ERROR)
-        << "Error: JAVA_HOME not set.";
+    return "";
   }
   return javahome;
 }
diff --git a/src/main/cpp/startup_options.cc b/src/main/cpp/startup_options.cc
index 1f9bc8b324..f2cc25dea0 100644
--- a/src/main/cpp/startup_options.cc
+++ b/src/main/cpp/startup_options.cc
@@ -392,30 +392,34 @@ blaze_exit_code::ExitCode StartupOptions::ProcessArgs(
   return blaze_exit_code::SUCCESS;
 }
 
-string StartupOptions::GetDefaultHostJavabase() const {
-  return blaze::GetDefaultHostJavabase();
+string StartupOptions::GetSystemJavabase() const {
+  return blaze::GetSystemJavabase();
 }
 
 string StartupOptions::GetHostJavabase() {
   // 1) Allow overriding the host_javabase via --host_javabase.
-  if (host_javabase.empty()) {
-    if (default_host_javabase.empty()) {
-      string bundled_jre_path = blaze_util::JoinPath(
-          install_base, "_embedded_binaries/embedded_tools/jdk");
-      if (blaze_util::CanExecuteFile(blaze_util::JoinPath(
-              bundled_jre_path, GetJavaBinaryUnderJavabase()))) {
-        // 2) Use a bundled JVM if we have one.
-        default_host_javabase = bundled_jre_path;
-      } else {
-        // 3) Otherwise fall back to using the default system JVM.
-        default_host_javabase = GetDefaultHostJavabase();
+  if (!host_javabase.empty()) {
+    return host_javabase;
+  }
+  if (default_host_javabase.empty()) {
+    string bundled_jre_path = blaze_util::JoinPath(
+        install_base, "_embedded_binaries/embedded_tools/jdk");
+    if (blaze_util::CanExecuteFile(blaze_util::JoinPath(
+            bundled_jre_path, GetJavaBinaryUnderJavabase()))) {
+      // 2) Use a bundled JVM if we have one.
+      default_host_javabase = bundled_jre_path;
+    } else {
+      // 3) Otherwise fall back to using the default system JVM.
+      string system_javabase = GetSystemJavabase();
+      if (system_javabase.empty()) {
+        BAZEL_DIE(blaze_exit_code::LOCAL_ENVIRONMENTAL_ERROR)
+            << "Could not find system javabase. Ensure JAVA_HOME is set, or "
+               "javac is on your PATH.";
       }
+      default_host_javabase = system_javabase;
     }
-
-    return default_host_javabase;
-  } else {
-    return host_javabase;
   }
+  return default_host_javabase;
 }
 
 string StartupOptions::GetExplicitHostJavabase() const {
diff --git a/src/main/cpp/startup_options.h b/src/main/cpp/startup_options.h
index 91a4ab7fd8..242a383fa3 100644
--- a/src/main/cpp/startup_options.h
+++ b/src/main/cpp/startup_options.h
@@ -133,9 +133,10 @@ class StartupOptions {
       const char *arg, const char *next_arg, const std::string &rcfile,
       const char **value, bool *is_processed, std::string *error) = 0;
 
-  // Return the default path to the JDK used to run Blaze itself
-  // (must be an absolute directory).
-  virtual std::string GetDefaultHostJavabase() const;
+  // Returns the absolute path to the user's local JDK install, to be used as
+  // the default target javabase and as a fall-back host_javabase. This is not
+  // the embedded JDK.
+  virtual std::string GetSystemJavabase() const;
 
   // Returns the path to the JVM. This should be called after parsing
   // the startup options.