[lit] Diagnose insufficient args to internal env

[jdenny]

Summary

Without this patch, failing to provide a subcommand to lit's internal
env results in either a python IndexError or an attempt to execute
the final env argument, such as FOO=1, as a command. This patch
diagnoses those cases with a more helpful message.

[stella.stamenova]

LGTM

[jdenny]

Thanks!

[jdenny]

Replace ValueError with InternalShellError as just discussed in D65697. I'll wait a little while to push in case someone wants to comment on this.

llvm/utils/lit/lit/TestRunner.py

for arg in seq:
             result.extend(bs_buf)
             result.append('"')
 
     return ''.join(result)
 
 # args are from 'export' or 'env' command.
 # Returns copy of args without those commands or their arguments.
 def updateEnv(env, args):
-    arg_idx = 1
+    arg_idx_next = len(args)
     unset_next_env_var = False
     for arg_idx, arg in enumerate(args[1:]):
         # Support for the -u flag (unsetting) for env command
         # e.g., env -u FOO -u BAR will remove both FOO and BAR
         # from the environment.
         if arg == '-u':
             unset_next_env_var = True
             continue
         if unset_next_env_var:
             unset_next_env_var = False
             if arg in env.env:
                 del env.env[arg]
             continue
 
         # Partition the string into KEY=VALUE.
         key, eq, val = arg.partition('=')
         # Stop if there was no equals.
         if eq == '':
+            arg_idx_next = arg_idx + 1
             break
         env.env[key] = val
-    return args[arg_idx+1:]
+    return args[arg_idx_next:]
 
 def executeBuiltinEcho(cmd, shenv):
     """Interpret a redirected echo command"""
     opened_files = []
     stdin, stdout, stderr = processRedirects(cmd, subprocess.PIPE, shenv,
                                              opened_files)
     if stdin != subprocess.PIPE or stderr != subprocess.PIPE:
         raise InternalShellError(
for i,j in enumerate(cmd.commands):
         cmd_shenv = shenv
         args = list(j.args)
         if j.args[0] == 'env':
             # Create a copy of the global environment and modify it for this one
             # command. There might be multiple envs in a pipeline:
             #   env FOO=1 llc < %s | env BAR=2 llvm-mc | FileCheck %s
             cmd_shenv = ShellEnvironment(shenv.cwd, shenv.env)
             args = updateEnv(cmd_shenv, j.args)
+            if not args:
+                raise InternalShellError(j,
+                                         "Error: 'env' requires a subcommand")
 
         stdin, stdout, stderr = processRedirects(j, default_stdin, cmd_shenv,
                                                  opened_files)
 
         # If stderr wants to come from stdout, but stdout isn't a pipe, then put
         # stderr on a pipe and treat it as stdout.
         if (stderr == subprocess.STDOUT and stdout != subprocess.PIPE):
             stderr = subprocess.PIPE

llvm/utils/lit/tests/Inputs/shtest-env/env-args-last-is-assign.txt

+# RUN: env FOO=1

llvm/utils/lit/tests/Inputs/shtest-env/env-args-last-is-u-arg.txt

+# RUN: env -u FOO

llvm/utils/lit/tests/Inputs/shtest-env/env-args-last-is-u.txt

+# RUN: env -u

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

+# RUN: env

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

 # Check the env command
 #
-# RUN: %{lit} -j 1 -a -v %{inputs}/shtest-env \
+# RUN: not %{lit} -j 1 -a -v %{inputs}/shtest-env \
 # RUN: | FileCheck -match-full-lines %s
 #
 # END.
 
 # Make sure env commands are included in printed commands.
 
+# CHECK: -- Testing: 7 tests{{.*}}
+
+# CHECK: FAIL: shtest-env :: env-args-last-is-assign.txt ({{[^)]*}})
+# CHECK: Error: 'env' requires a subcommand
+# CHECK: error: command failed with exit status: {{.*}}
+
+# CHECK: FAIL: shtest-env :: env-args-last-is-u-arg.txt ({{[^)]*}})
+# CHECK: Error: 'env' requires a subcommand
+# CHECK: error: command failed with exit status: {{.*}}
+
+# CHECK: FAIL: shtest-env :: env-args-last-is-u.txt ({{[^)]*}})
+# CHECK: Error: 'env' requires a subcommand
+# CHECK: error: command failed with exit status: {{.*}}
+
+# CHECK: FAIL: shtest-env :: env-args-none.txt ({{[^)]*}})
+# CHECK: Error: 'env' requires a subcommand
+# CHECK: error: command failed with exit status: {{.*}}
+
 # CHECK: PASS: shtest-env :: env-u.txt ({{[^)]*}})
 # CHECK: $ "{{[^"]*}}" "print_environment.py"
 # CHECK: $ "env" "-u" "FOO" "{{[^"]*}}" "print_environment.py"
 # CHECK: $ "env" "-u" "FOO" "-u" "BAR" "{{[^"]*}}" "print_environment.py"
 
 # CHECK: PASS: shtest-env :: env.txt ({{[^)]*}})
 # CHECK: $ "env" "A_FOO=999" "{{[^"]*}}" "print_environment.py"
 # CHECK: $ "env" "A_FOO=1" "B_BAR=2" "C_OOF=3" "{{[^"]*}}" "print_environment.py"
 
 # CHECK: PASS: shtest-env :: mixed.txt ({{[^)]*}})
 # CHECK: $ "env" "A_FOO=999" "-u" "FOO" "{{[^"]*}}" "print_environment.py"
 # CHECK: $ "env" "A_FOO=1" "-u" "FOO" "B_BAR=2" "-u" "BAR" "C_OOF=3" "{{[^"]*}}" "print_environment.py"
 
 # CHECK: Expected Passes : 3
+# CHECK: Unexpected Failures: 4
+# CHECK-NOT: {{.}}