[llvm-lit] Update TestRunner.py for Redirection Handling and a test in lit

Added Redirection Handling: Enhanced TestRunner.py to correctly handle cases
where the env command is run without arguments. It now checks if there are
no arguments and, when redirection is specified, writes the environment
variables directly to the redirected file or a temporary file. Test for
Redirection Behavior: Created a new test in lit's internal shell to verify that
when the env command is executedwithout arguments and with redirection, it
properly outputs the environment variables to the specified file.

Author: Harini0924

llvm/utils/lit/lit/TestRunner.py

@@ -746,11 +746,25 @@ def _executeShCmd(cmd, shenv, results, timeoutHelper):
                     env_str = "\n".join(
                         f"{key}={value}" for key, value in sorted(cmd_shenv.env.items())
                     )
-                    results.append(
-                        ShellCommandResult(
-                            j, env_str, "", 0, timeoutHelper.timeoutReached(), []
-                        )
+                    # Process redirections.
+                    stdin, stdout, stderr = processRedirects(
+                        j, default_stdin, cmd_shenv, opened_files
                     )
+                    if stdout != default_stdin:
+                        # Write directly to the redirected file (stdout).
+                        stdout.write(env_str)
+                        results.append(
+                            ShellCommandResult(
+                                j, "", "", 0, timeoutHelper.timeoutReached(), []
+                            )
+                        )
+                    else:
+                        # Capture the output for cases without redirection.
+                        results.append(
+                            ShellCommandResult(
+                                j, env_str, "", 0, timeoutHelper.timeoutReached(), []
+                            )
+                        )
                     return 0
             elif args[0] == "not":
                 not_args.append(args.pop(0))

llvm/utils/lit/tests/Inputs/shtest-env-positive/env-temp-redirect.txt

@@ -0,0 +1,7 @@
+## Test the env command with output redirection to a file.
+# RUN: rm -f %t
+# RUN: env > %t
+# RUN: FileCheck %s < %t
+
+# CHECK: BAR=2
+# CHECK: FOO=1

llvm/utils/lit/tests/shtest-env-positive.py

@@ -7,7 +7,7 @@
 
 ## Test the env command's successful executions.
 
-# CHECK: -- Testing: 9 tests{{.*}}
+# CHECK: -- Testing: 10 tests{{.*}}
 
 # CHECK: PASS: shtest-env :: env-args-last-is-assign.txt ({{[^)]*}})
 # CHECK: env FOO=1
@@ -47,6 +47,12 @@
 # CHECK-NOT: # error:
 # CHECK: --
 
+# CHECK: PASS: shtest-env :: env-temp-redirect.txt ({{[^)]*}})
+# CHECK: env {{.*}}/env-temp-redirect.txt.tmp
+# CHECK: # executed command: env
+# CHECK-NOT: # error:
+# CHECK: --
+
 # CHECK: PASS: shtest-env :: env-u.txt ({{[^)]*}})
 # CHECK: env -u FOO | {{.*}}
 # CHECK: # executed command: env -u FOO
@@ -65,6 +71,6 @@
 # CHECK-NOT: # error:
 # CHECK: --
 
-# CHECK: Total Discovered Tests: 9
-# CHECK: Passed: 9 {{\([0-9]*\.[0-9]*%\)}}
+# CHECK: Total Discovered Tests: 10
+# CHECK: Passed: 10 {{\([0-9]*\.[0-9]*%\)}}
 # CHECK-NOT: {{.}}