[lit] Add support for deleting symlinks to directories without -r

Before this change, rm would assume that a symlink to a directory was
actually a directory and require the recursive flag to be passed,
differing from other shells. Given the change in lit is about the same
length as the test change would be (minus tests), I think it makes sense
to just support this in the internal shell.

Reviewers: cmtice, petrhosek, ilovepi

Reviewed By: petrhosek, cmtice, ilovepi

Pull Request: llvm#158464

Author: boomanaiden154

llvm/utils/lit/lit/TestRunner.py

@@ -516,7 +516,9 @@ def on_rm_error(func, path, exc_info):
         if force and not os.path.exists(path):
             continue
         try:
-            if os.path.isdir(path):
+            if os.path.islink(path):
+                os.remove(path)
+            elif os.path.isdir(path):
                 if not recursive:
                     stderr.write("Error: %s is a directory\n" % path)
                     exitCode = 1

llvm/utils/lit/tests/Inputs/shtest-shell-symlinks/lit.cfg

@@ -0,0 +1,7 @@
+import lit.formats
+
+config.name = "shtest-shell"
+config.suffixes = [".txt"]
+config.test_format = lit.formats.ShTest()
+config.test_source_root = None
+config.test_exec_root = None

llvm/utils/lit/tests/Inputs/shtest-shell-symlinks/rm-symlink-dir.txt

@@ -0,0 +1,5 @@
+# Check that we can delete a symlink to a folder without -r
+#
+# RUN: mkdir %t.dir
+# RUN: ln -s %t.dir %t.symlink
+# RUN: rm %t.symlink

llvm/utils/lit/tests/shtest-shell-symlinks.py

@@ -0,0 +1,9 @@
+# Check that the internal shell builtins correctly handle cases involving
+# symlinks.
+
+# REQUIRES: symlinks
+# RUN: echo test
+# RUN: %{lit} -v %{inputs}/shtest-shell-symlinks | FileCheck %s
+
+# CHECK: -- Testing: 1 test{{.*}}
+# CHECK: PASS: shtest-shell :: rm-symlink-dir.txt