[core] fix saving TEnv with ROOTENV_USER_PATH set

(cherry picked from commit caf87c6)

Author: jblomer

core/base/inc/TEnv.h

@@ -87,6 +87,7 @@ class TEnv : public TObject {
    TEnv& operator=(const TEnv&) = delete;
 
    const char       *Getvalue(const char *name) const;
+   const char       *GetUserDirectory() const;
 
 public:
    TEnv(const char *name="");

core/base/src/TEnv.cxx

@@ -389,6 +389,16 @@ TString TEnvRec::ExpandValue(const char *value)
    return val;
 }
 
+////////////////////////////////////////////////////////////////////////////////
+/// Returns the home directory or, if set, the value of the environment variable
+/// ROOTENV_USER_PATH.
+const char *TEnv::GetUserDirectory() const
+{
+   const auto customPath = gSystem->Getenv("ROOTENV_USER_PATH");
+   if (customPath)
+      return customPath;
+   return gSystem->HomeDirectory();
+}
 
 ////////////////////////////////////////////////////////////////////////////////
 /// Create a resource table and read the (possibly) three resource files,
@@ -422,16 +432,10 @@ TEnv::TEnv(const char *name)
       const char *s = gSystem->PrependPathName(TROOT::GetEtcDir(), sname);
       ReadFile(s, kEnvGlobal);
       if (!gSystem->Getenv("ROOTENV_NO_HOME")) {
-         if (const auto rootrcPath = gSystem->Getenv("ROOTENV_USER_PATH")) {
-            TString temp(name);
-            const char *s1 = gSystem->PrependPathName(rootrcPath, temp);
-            ReadFile(s1, kEnvUser);
-         } else {
-            TString temp(name);
-            const char *s1 = gSystem->PrependPathName(gSystem->HomeDirectory(), temp);
-            ReadFile(s1, kEnvUser);
-         }
-         if (strcmp(gSystem->HomeDirectory(), gSystem->WorkingDirectory())) {
+         TString temp(name);
+         gSystem->PrependPathName(GetUserDirectory(), temp);
+         ReadFile(temp.Data(), kEnvUser);
+         if (strcmp(GetUserDirectory(), gSystem->WorkingDirectory())) {
             ReadFile(name, kEnvLocal);
          }
       } else {
@@ -693,16 +697,16 @@ void TEnv::SaveLevel(EEnvLevel level)
    FILE     *ifp, *ofp;
 
    if (level == kEnvGlobal) {
-
       TString sname = "system";
       sname += fRcName;
       rootrcdir = gSystem->PrependPathName(TROOT::GetEtcDir(), sname);
    } else if (level == kEnvUser) {
-      rootrcdir = gSystem->PrependPathName(gSystem->HomeDirectory(), fRcName);
-   } else if (level == kEnvLocal)
+      rootrcdir = gSystem->PrependPathName(GetUserDirectory(), fRcName);
+   } else if (level == kEnvLocal) {
       rootrcdir = fRcName;
-   else
+   } else {
       return;
+   }
 
    if ((ofp = fopen(TString::Format("%s.new", rootrcdir.Data()).Data(), "w"))) {
       ifp = fopen(rootrcdir.Data(), "r");

core/base/test/CMakeLists.txt

@@ -22,6 +22,8 @@ endif()
 target_compile_options(CoreBaseTests PRIVATE -DEXPECTED_SHARED_LIBRARY_DIR="${localruntimedir}")
 target_compile_options(CoreBaseTests PRIVATE -DEXPECTED_INCLUDE_DIR="${CMAKE_BINARY_DIR}/include")
 
+ROOT_ADD_GTEST(CoreEnvTests TEnvTests.cxx LIBRARIES Core)
+
 ROOT_ADD_GTEST(CoreErrorTests TErrorTests.cxx LIBRARIES Core)
 
 ROOT_ADD_GTEST(CoreSystemTests TSystemTests.cxx LIBRARIES Core)

core/base/test/TEnvTests.cxx

@@ -0,0 +1,49 @@
+#include "gtest/gtest.h"
+
+#include "TEnv.h"
+#include "TString.h"
+#include "TSystem.h"
+#include "TUUID.h"
+
+#include <string>
+
+TEST(TEnv, ROOTENV_USER_PATH)
+{
+   auto uuid = TUUID::UUIDv4();
+
+   // Create directories structure <UUID>/local with user-level config in <UUID> and local-level config
+   // in <UUID>/local
+   const TString rcname = "testenv";
+   const TString userDir = uuid.AsString();
+   TString userConfig = rcname;
+   gSystem->PrependPathName(userDir.Data(), userConfig);
+   const TString userBak = userConfig + ".bak";
+   TString localDir = "local";
+   gSystem->PrependPathName(userDir, localDir);
+   TString localConfig = rcname;
+   gSystem->PrependPathName(localDir.Data(), localConfig);
+   TString homeConfig = rcname;
+   gSystem->PrependPathName(gSystem->HomeDirectory(), homeConfig);
+
+   localDir.ReplaceAll("\\", "\\\\");
+   ASSERT_EQ(0, gSystem->mkdir(localDir.Data(), /*recursive=*/true));
+
+   gSystem->Setenv("ROOTENV_USER_PATH", userDir.Data());
+   EXPECT_TRUE(gSystem->AccessPathName(localConfig.Data()));
+   EXPECT_TRUE(gSystem->AccessPathName(userConfig.Data()));
+
+   TEnv env("testenv");
+   env.SetValue("EnvRec");
+   EXPECT_EQ(1, env.GetValue("EnvRec", 0));
+   env.SaveLevel(kEnvUser);
+
+   EXPECT_TRUE(gSystem->AccessPathName(localConfig.Data()));
+   EXPECT_FALSE(gSystem->AccessPathName(userConfig.Data()));
+   EXPECT_TRUE(gSystem->AccessPathName(homeConfig.Data()));
+
+   EXPECT_EQ(0, gSystem->Unlink(localDir.Data()));
+   EXPECT_EQ(0, gSystem->Unlink(userConfig.Data()));
+   EXPECT_EQ(0, gSystem->Unlink(userBak.Data()));
+   EXPECT_EQ(0, gSystem->Unlink(userDir.Data()));
+   gSystem->Unsetenv("ROOTENV_USER_PATH");
+}