[llvm-lit] Resolve env subcommand required error

This patch addresses an issue where calling env without any arguments incorrectly returns
a "requires subcommand" message. The patch modifies the env command to properly display
the current environment variables even when no arguments are provided. Additionally,
the test cases have been updated: instead of returning an error, the tests now pass
and check if the environment variables are output correctly.

Author: Harini0924

llvm/utils/lit/lit/TestRunner.py

@@ -744,7 +744,9 @@ def _executeShCmd(cmd, shenv, results, timeoutHelper):
                 args = updateEnv(cmd_shenv, args)
                 if not args:
                     # Return the environment variables if no argument is provided 
-                    return {key: value for key, value in cmd_shenv.env.items()}
+                    env_str = "\n".join(f"{key}={value}" for key, value in cmd_shenv.env.items())
+                    results.append(ShellCommandResult(j, env_str, "", 0 , timeoutHelper.timeoutReached(), []))
+                    return 0
             elif args[0] == "not":
                 not_args.append(args.pop(0))
                 not_count += 1

llvm/utils/lit/tests/Inputs/shtest-env/env-args-none.txt

@@ -1 +1,30 @@
-# RUN: env
+# Check Default Environment
+# RUN: env | FileCheck -check-prefix=CHECK-2-EMPTY %s
+#
+# CHECK-2-EMPTY: BAR = 2
+# CHECK-2-EMPTY: FOO = 1
+
+# Set Environment Variables
+# RUN: env FOO=2 BAR=1 | FileCheck -check-prefix=CHECK-2-VAL %s
+#
+# CHECK-2-VAL: BAR = 1
+# CHECK-2-VAL: FOO = 2
+
+# Unset Environment Variables
+# RUN: env -u FOO -u BAR | FileCheck -check-prefix=CHECK-2-U %s
+#
+# CHECK-2-U-NOT: BAR
+# CHECK-2-U-NOT: FOO
+
+# Mixed Set and Unset Environment Variables
+# RUN: env -u FOO BAR=1 -u BAR FOO=2 | FileCheck -check-prefix=CHECK-2-U-VAL %s
+#
+# CHECK-2-U-VAL-NOT: BAR
+# CHECK-2-U-VAL: FOO = 2
+ 
+# Mixed Set and Unset with Additional Variable
+# RUN: env -u FOO BAR=1 -u BAR FOO=2 BAZ=3 | FileCheck -check-prefix=CHECK-3 %s
+#
+# CHECK-3-NOT: BAR
+# CHECK-3: BAZ = 3
+# CHECK-3: FOO = 2

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

@@ -9,35 +9,35 @@
 
 # CHECK: -- Testing: 16 tests{{.*}}
 
-# CHECK: FAIL: shtest-env :: env-args-last-is-assign.txt ({{[^)]*}})
+# CHECK: PASS: shtest-env :: env-args-last-is-assign.txt ({{[^)]*}})
 # CHECK: env FOO=1
 # CHECK: # executed command: env FOO=1
-# CHECK: # | Error: 'env' requires a subcommand
-# CHECK: # error: command failed with exit status: {{.*}}
+# CHECK-NOT: {{^[^#]}} 
+# CHECK: --
 
-# CHECK: FAIL: shtest-env :: env-args-last-is-u-arg.txt ({{[^)]*}})
+# CHECK: PASS: shtest-env :: env-args-last-is-u-arg.txt ({{[^)]*}})
 # CHECK: env -u FOO
 # CHECK: # executed command: env -u FOO
-# CHECK: # | Error: 'env' requires a subcommand
-# CHECK: # error: command failed with exit status: {{.*}}
+# CHECK-NOT: {{^[^#]}} 
+# CHECK: --
 
-# CHECK: FAIL: shtest-env :: env-args-last-is-u.txt ({{[^)]*}})
+# CHECK: PASS: shtest-env :: env-args-last-is-u.txt ({{[^)]*}})
 # CHECK: env -u
 # CHECK: # executed command: env -u
-# CHECK: # | Error: 'env' requires a subcommand
-# CHECK: # error: command failed with exit status: {{.*}}
+# CHECK-NOT: {{^[^#]}}
+# CHECK: --
 
-# CHECK: FAIL: shtest-env :: env-args-nested-none.txt ({{[^)]*}})
+# CHECK: PASS: shtest-env :: env-args-nested-none.txt ({{[^)]*}})
 # CHECK: env env env
 # CHECK: # executed command: env env env
-# CHECK: # | Error: 'env' requires a subcommand
-# CHECK: # error: command failed with exit status: {{.*}}
+# CHECK-NOT: {{^[^#]}}
+# CHECK: --
 
-# CHECK: FAIL: shtest-env :: env-args-none.txt ({{[^)]*}})
+# CHECK: PASS: shtest-env :: env-args-none.txt ({{[^)]*}})
 # CHECK: env
 # CHECK: # executed command: env
-# CHECK: # | Error: 'env' requires a subcommand
-# CHECK: # error: command failed with exit status: {{.*}}
+# CHECK-NOT: {{^[^#]}}
+# CHECK: --
 
 # CHECK: FAIL: shtest-env :: env-calls-cd.txt ({{[^)]*}})
 # CHECK: env -u FOO BAR=3 cd foobar
@@ -121,6 +121,6 @@
 # CHECK: --
 
 # CHECK: Total Discovered Tests: 16
-# CHECK: Passed:  4 {{\([0-9]*\.[0-9]*%\)}}
-# CHECK: Failed: 12 {{\([0-9]*\.[0-9]*%\)}}
+# CHECK: Passed:  9 {{\([0-9]*\.[0-9]*%\)}}
+# CHECK: Failed: 7 {{\([0-9]*\.[0-9]*%\)}}
 # CHECK-NOT: {{.}}