[PATCH v2] scripts/sbom: catch ValueError from malformed shell quoting

[Carlos Sampaio Ribeiro <otakurack@gmail.com>]

parse_inputs_from_commands() only caught CmdParsingError and IndexError
when dispatching to command parsers, but several parsers call
shlex.split() internally, which raises ValueError on malformed shell
quoting (e.g. an unterminated quote). This exception was not caught,
so a single malformed build command would abort SBOM generation
entirely, even with fail_on_unknown_build_command=False, defeating the
purpose of tolerant mode.

The issue was found while reviewing the exception handling around the
saved-command parser after running its existing tests. It can be
reproduced with:

    parse_inputs_from_commands('gcc "unterminated',
                               fail_on_unknown_build_command=False)

Catch ValueError alongside CmdParsingError and IndexError so such
commands are logged as a warning/error and skipped instead of aborting
the whole run.

Add tests covering malformed shell quoting and a missing positional
argument.

Signed-off-by: Carlos Sampaio Ribeiro <otakurack@gmail.com>
---
Changes in v2:
- Use my real name in the From and Signed-off-by fields.
- Explain how the missing ValueError handling was found.

 .../savedcmd_parser/savedcmd_parser.py        |  2 +-
 .../tests/cmd_graph/test_savedcmd_parser.py   | 25 +++++++++++++++++++
 2 files changed, 26 insertions(+), 1 deletion(-)

diff --git a/scripts/sbom/sbom/cmd_graph/savedcmd_parser/savedcmd_parser.py b/scripts/sbom/sbom/cmd_graph/savedcmd_parser/savedcmd_parser.py
index 6a7ea4787aa1..d2ca842a7849 100644
--- a/scripts/sbom/sbom/cmd_graph/savedcmd_parser/savedcmd_parser.py
+++ b/scripts/sbom/sbom/cmd_graph/savedcmd_parser/savedcmd_parser.py
@@ -57,7 +57,7 @@ def parse_inputs_from_commands(
         try:
             inputs = matched_parser(single_command)
             input_files.extend(inputs)
-        except (CmdParsingError, IndexError) as e:
+        except (CmdParsingError, IndexError, ValueError) as e:
             log_error_or_warning(
                 "Skipped parsing command {single_command} because of command parsing error: {error_message}",
                 single_command=single_command,
diff --git a/scripts/sbom/tests/cmd_graph/test_savedcmd_parser.py b/scripts/sbom/tests/cmd_graph/test_savedcmd_parser.py
index a061a748e1bf..d7776f072e03 100644
--- a/scripts/sbom/tests/cmd_graph/test_savedcmd_parser.py
+++ b/scripts/sbom/tests/cmd_graph/test_savedcmd_parser.py
@@ -19,6 +19,31 @@ class TestSavedCmdParser(unittest.TestCase):
         errors = sbom_logging._error_logger._message_counts # type: ignore
         self.assertEqual(errors, {})
 
+    # Error handling tests
+    def test_malformed_shell_quoting(self):
+        command = 'gcc "unterminated'
+        with patch.object(sbom_logging, "warning") as warning:
+            parsed = parse_inputs_from_commands(command, fail_on_unknown_build_command=False)
+
+        self.assertEqual(parsed, [])
+        warning.assert_called_once_with(
+            "Skipped parsing command {single_command} because of command parsing error: {error_message}",
+            single_command=command,
+            error_message="No closing quotation",
+        )
+
+    def test_missing_positional_argument(self):
+        command = "objcopy"
+        with patch.object(sbom_logging, "warning") as warning:
+            parsed = parse_inputs_from_commands(command, fail_on_unknown_build_command=False)
+
+        self.assertEqual(parsed, [])
+        warning.assert_called_once_with(
+            "Skipped parsing command {single_command} because of command parsing error: {error_message}",
+            single_command=command,
+            error_message="list index out of range",
+        )
+
     # Compound command tests
     def test_dd_cat(self):
         cmd = "(dd if=arch/x86/boot/setup.bin bs=4k conv=sync status=none; cat arch/x86/boot/vmlinux.bin) >arch/x86/boot/bzImage"
-- 
2.54.0.windows.1