Test and fix root symlink edge case in runfiles library

Due to incomplete test coverage for the case of a root symlink named like a Bazel module, the Bash runfiles libraries behaved incorrectly in this case. This commit fixes that and adds proper test coverage for all libraries by adding repo mappings that conflict with the existing rlocation testcase for `config.json`.

Closes #17317.

PiperOrigin-RevId: 505873412
Change-Id: I72019d329b72cab9cf893deb714da8889d371617

tools/bash/runfiles/runfiles.bash

@@ -142,7 +142,10 @@ function rlocation() {
 
   if [[ -f "$RUNFILES_REPO_MAPPING" ]]; then
     local -r target_repo_apparent_name=$(echo "$1" | cut -d / -f 1)
-    local -r remainder=$(echo "$1" | cut -d / -f 2-)
+     # Use -s to get an empty remainder if the argument does not contain a slash.
+    # The repo mapping should not be applied to single segment paths, which may
+    # be root symlinks.
+    local -r remainder=$(echo "$1" | cut -s -d / -f 2-)
     if [[ -n "$remainder" ]]; then
       if [[ -z "${2+x}" ]]; then
         local -r source_repo=$(runfiles_current_repository 2)

tools/bash/runfiles/runfiles_test.bash

@@ -216,10 +216,12 @@ function test_directory_based_runfiles_with_repo_mapping_from_main() {
   export RUNFILES_DIR=${tmpdir}/mock/runfiles
   mkdir -p "$RUNFILES_DIR"
   cat > "$RUNFILES_DIR/_repo_mapping" <<EOF
+,config.json,config.json~1.2.3
 ,my_module,_main
 ,my_protobuf,protobuf~3.19.2
 ,my_workspace,_main
 protobuf~3.19.2,protobuf,protobuf~3.19.2
+protobuf~3.19.2,config.json,config.json~1.2.3
 EOF
   export RUNFILES_MANIFEST_FILE=
   source "$runfiles_lib_path"
@@ -258,10 +260,12 @@ function test_directory_based_runfiles_with_repo_mapping_from_other_repo() {
   export RUNFILES_DIR=${tmpdir}/mock/runfiles
   mkdir -p "$RUNFILES_DIR"
   cat > "$RUNFILES_DIR/_repo_mapping" <<EOF
+,config.json,config.json~1.2.3
 ,my_module,_main
 ,my_protobuf,protobuf~3.19.2
 ,my_workspace,_main
 protobuf~3.19.2,protobuf,protobuf~3.19.2
+protobuf~3.19.2,config.json,config.json~1.2.3
 EOF
   export RUNFILES_MANIFEST_FILE=
   source "$runfiles_lib_path"
@@ -296,10 +300,12 @@ function test_manifest_based_runfiles_with_repo_mapping_from_main() {
   local tmpdir="$(mktemp -d $TEST_TMPDIR/tmp.XXXXXXXX)"
 
   cat > "$tmpdir/foo.repo_mapping" <<EOF
+,config.json,config.json~1.2.3
 ,my_module,_main
 ,my_protobuf,protobuf~3.19.2
 ,my_workspace,_main
 protobuf~3.19.2,protobuf,protobuf~3.19.2
+protobuf~3.19.2,config.json,config.json~1.2.3
 EOF
   export RUNFILES_DIR=
   export RUNFILES_MANIFEST_FILE="$tmpdir/foo.runfiles_manifest"
@@ -344,10 +350,12 @@ function test_manifest_based_runfiles_with_repo_mapping_from_other_repo() {
   local tmpdir="$(mktemp -d $TEST_TMPDIR/tmp.XXXXXXXX)"
 
   cat > "$tmpdir/foo.repo_mapping" <<EOF
+,config.json,config.json~1.2.3
 ,my_module,_main
 ,my_protobuf,protobuf~3.19.2
 ,my_workspace,_main
 protobuf~3.19.2,protobuf,protobuf~3.19.2
+protobuf~3.19.2,config.json,config.json~1.2.3
 EOF
   export RUNFILES_DIR=
   export RUNFILES_MANIFEST_FILE="$tmpdir/foo.runfiles_manifest"

tools/cpp/runfiles/runfiles_test.cc

@@ -586,10 +586,12 @@ TEST_F(RunfilesTest, PathsFromEnvVars) {
 
 TEST_F(RunfilesTest, ManifestBasedRlocationWithRepoMapping_fromMain) {
   string uid = LINE_AS_STRING();
-  unique_ptr<MockFile> rm(MockFile::Create(
-      "foo" + uid + ".repo_mapping",
-      {",my_module,_main", ",my_protobuf,protobuf~3.19.2",
-       ",my_workspace,_main", "protobuf~3.19.2,protobuf,protobuf~3.19.2"}));
+  unique_ptr<MockFile> rm(
+      MockFile::Create("foo" + uid + ".repo_mapping",
+                       {",config.json,config.json~1.2.3", ",my_module,_main",
+                        ",my_protobuf,protobuf~3.19.2", ",my_workspace,_main",
+                        "protobuf~3.19.2,config.json,config.json~1.2.3",
+                        "protobuf~3.19.2,protobuf,protobuf~3.19.2"}));
   ASSERT_TRUE(rm != nullptr);
   unique_ptr<MockFile> mf(MockFile::Create(
       "foo" + uid + ".runfiles_manifest",
@@ -644,10 +646,12 @@ TEST_F(RunfilesTest, ManifestBasedRlocationWithRepoMapping_fromMain) {
 
 TEST_F(RunfilesTest, ManifestBasedRlocationWithRepoMapping_fromOtherRepo) {
   string uid = LINE_AS_STRING();
-  unique_ptr<MockFile> rm(MockFile::Create(
-      "foo" + uid + ".repo_mapping",
-      {",my_module,_main", ",my_protobuf,protobuf~3.19.2",
-       ",my_workspace,_main", "protobuf~3.19.2,protobuf,protobuf~3.19.2"}));
+  unique_ptr<MockFile> rm(
+      MockFile::Create("foo" + uid + ".repo_mapping",
+                       {",config.json,config.json~1.2.3", ",my_module,_main",
+                        ",my_protobuf,protobuf~3.19.2", ",my_workspace,_main",
+                        "protobuf~3.19.2,config.json,config.json~1.2.3",
+                        "protobuf~3.19.2,protobuf,protobuf~3.19.2"}));
   ASSERT_TRUE(rm != nullptr);
   unique_ptr<MockFile> mf(MockFile::Create(
       "foo" + uid + ".runfiles_manifest",
@@ -699,10 +703,12 @@ TEST_F(RunfilesTest, ManifestBasedRlocationWithRepoMapping_fromOtherRepo) {
 
 TEST_F(RunfilesTest, DirectoryBasedRlocationWithRepoMapping_fromMain) {
   string uid = LINE_AS_STRING();
-  unique_ptr<MockFile> rm(MockFile::Create(
-      "foo" + uid + ".runfiles/_repo_mapping",
-      {",my_module,_main", ",my_protobuf,protobuf~3.19.2",
-       ",my_workspace,_main", "protobuf~3.19.2,protobuf,protobuf~3.19.2"}));
+  unique_ptr<MockFile> rm(
+      MockFile::Create("foo" + uid + ".runfiles/_repo_mapping",
+                       {",config.json,config.json~1.2.3", ",my_module,_main",
+                        ",my_protobuf,protobuf~3.19.2", ",my_workspace,_main",
+                        "protobuf~3.19.2,config.json,config.json~1.2.3",
+                        "protobuf~3.19.2,protobuf,protobuf~3.19.2"}));
   ASSERT_TRUE(rm != nullptr);
   string dir = rm->DirName();
   string argv0(dir.substr(0, dir.size() - string(".runfiles").size()));
@@ -746,10 +752,12 @@ TEST_F(RunfilesTest, DirectoryBasedRlocationWithRepoMapping_fromMain) {
 
 TEST_F(RunfilesTest, DirectoryBasedRlocationWithRepoMapping_fromOtherRepo) {
   string uid = LINE_AS_STRING();
-  unique_ptr<MockFile> rm(MockFile::Create(
-      "foo" + uid + ".runfiles/_repo_mapping",
-      {",my_module,_main", ",my_protobuf,protobuf~3.19.2",
-       ",my_workspace,_main", "protobuf~3.19.2,protobuf,protobuf~3.19.2"}));
+  unique_ptr<MockFile> rm(
+      MockFile::Create("foo" + uid + ".runfiles/_repo_mapping",
+                       {",config.json,config.json~1.2.3", ",my_module,_main",
+                        ",my_protobuf,protobuf~3.19.2", ",my_workspace,_main",
+                        "protobuf~3.19.2,config.json,config.json~1.2.3",
+                        "protobuf~3.19.2,protobuf,protobuf~3.19.2"}));
   ASSERT_TRUE(rm != nullptr);
   string dir = rm->DirName();
   string argv0(dir.substr(0, dir.size() - string(".runfiles").size()));
@@ -790,10 +798,12 @@ TEST_F(RunfilesTest, DirectoryBasedRlocationWithRepoMapping_fromOtherRepo) {
 TEST_F(RunfilesTest,
        DirectoryBasedRlocationWithRepoMapping_fromOtherRepo_withSourceRepo) {
   string uid = LINE_AS_STRING();
-  unique_ptr<MockFile> rm(MockFile::Create(
-      "foo" + uid + ".runfiles/_repo_mapping",
-      {",my_module,_main", ",my_protobuf,protobuf~3.19.2",
-       ",my_workspace,_main", "protobuf~3.19.2,protobuf,protobuf~3.19.2"}));
+  unique_ptr<MockFile> rm(
+      MockFile::Create("foo" + uid + ".runfiles/_repo_mapping",
+                       {",config.json,config.json~1.2.3", ",my_module,_main",
+                        ",my_protobuf,protobuf~3.19.2", ",my_workspace,_main",
+                        "protobuf~3.19.2,config.json,config.json~1.2.3",
+                        "protobuf~3.19.2,protobuf,protobuf~3.19.2"}));
   ASSERT_TRUE(rm != nullptr);
   string dir = rm->DirName();
   string argv0(dir.substr(0, dir.size() - string(".runfiles").size()));

tools/java/runfiles/testing/RunfilesTest.java

@@ -264,9 +264,11 @@ public void testManifestBasedRlocationWithRepoMapping_fromMain() throws Exceptio
         tempFile(
             "foo.repo_mapping",
             ImmutableList.of(
+                ",config.json,config.json~1.2.3",
                 ",my_module,_main",
                 ",my_protobuf,protobuf~3.19.2",
                 ",my_workspace,_main",
+                "protobuf~3.19.2,config.json,config.json~1.2.3",
                 "protobuf~3.19.2,protobuf,protobuf~3.19.2"));
     Path mf =
         tempFile(
@@ -318,9 +320,11 @@ public void testManifestBasedRlocationUnmapped() throws Exception {
         tempFile(
             "foo.repo_mapping",
             ImmutableList.of(
+                ",config.json,config.json~1.2.3",
                 ",my_module,_main",
                 ",my_protobuf,protobuf~3.19.2",
                 ",my_workspace,_main",
+                "protobuf~3.19.2,config.json,config.json~1.2.3",
                 "protobuf~3.19.2,protobuf,protobuf~3.19.2"));
     Path mf =
         tempFile(
@@ -367,9 +371,11 @@ public void testManifestBasedRlocationWithRepoMapping_fromOtherRepo() throws Exc
         tempFile(
             "foo.repo_mapping",
             ImmutableList.of(
+                ",config.json,config.json~1.2.3",
                 ",my_module,_main",
                 ",my_protobuf,protobuf~3.19.2",
                 ",my_workspace,_main",
+                "protobuf~3.19.2,config.json,config.json~1.2.3",
                 "protobuf~3.19.2,protobuf,protobuf~3.19.2"));
     Path mf =
         tempFile(
@@ -419,9 +425,11 @@ public void testDirectoryBasedRlocationWithRepoMapping_fromMain() throws Excepti
         tempFile(
             dir.resolve("_repo_mapping").toString(),
             ImmutableList.of(
+                ",config.json,config.json~1.2.3",
                 ",my_module,_main",
                 ",my_protobuf,protobuf~3.19.2",
                 ",my_workspace,_main",
+                "protobuf~3.19.2,config.json,config.json~1.2.3",
                 "protobuf~3.19.2,protobuf,protobuf~3.19.2"));
     Runfiles r = Runfiles.createDirectoryBasedForTesting(dir.toString()).withSourceRepository("");
 
@@ -458,9 +466,11 @@ public void testDirectoryBasedRlocationUnmapped() throws Exception {
         tempFile(
             dir.resolve("_repo_mapping").toString(),
             ImmutableList.of(
+                ",config.json,config.json~1.2.3",
                 ",my_module,_main",
                 ",my_protobuf,protobuf~3.19.2",
                 ",my_workspace,_main",
+                "protobuf~3.19.2,config.json,config.json~1.2.3",
                 "protobuf~3.19.2,protobuf,protobuf~3.19.2"));
     Runfiles r = Runfiles.createDirectoryBasedForTesting(dir.toString()).unmapped();
 
@@ -497,9 +507,11 @@ public void testDirectoryBasedRlocationWithRepoMapping_fromOtherRepo() throws Ex
         tempFile(
             dir.resolve("_repo_mapping").toString(),
             ImmutableList.of(
+                ",config.json,config.json~1.2.3",
                 ",my_module,_main",
                 ",my_protobuf,protobuf~3.19.2",
                 ",my_workspace,_main",
+                "protobuf~3.19.2,config.json,config.json~1.2.3",
                 "protobuf~3.19.2,protobuf,protobuf~3.19.2"));
     Runfiles r =
         Runfiles.createDirectoryBasedForTesting(dir.toString())