[PATCH v2 00/28] kernel-doc: use a C lexical tokenizer for transforms

Mauro Carvalho Chehab
2026-03-12T14:54:57Z

Hi Jon,

Sorry for respamming this one too quick. It ends that v1 had some
bugs causing it to fail on several cases. I opted to add extra
patches in the end. This way, it better integrates with kdoc_re.
As part of it, now c_lex will output file name when reporting
errors. With that regards, only more serious errors will raise
an exception. They are meant to indicate problems at kernel-doc
itself. Parsing errors are now using the same warning approach
as kdoc_parser.

I also added a filter at Ctokenizer __str__() logic for the
string convertion to drop some weirdness whitespaces and uneeded
";" characters at the output.

Finally, v2 address the undefined behavior about private: comment
propagation.

This patch series change how kdoc parser handles macro replacements.

Instead of heavily relying on regular expressions that can sometimes
be very complex, it uses a C lexical tokenizer. This ensures that
BEGIN/END blocks on functions and structs are properly handled,
even when nested.

Checking before/after the patch series, for both man pages and
rst only had:
- whitespace differences;
- struct_group macros now are shown as inner anonimous structs
as it should be.

Also, I didn't notice any relevant change on the documentation build
time. With that regards, right now, every time a CMatch replacement
rule takes in place, it does:

for each transform:
- tokenizes the source code;
- handle CMatch;
- convert tokens back to a string.

A possible optimization would be to do, instead:

- tokenizes source code;
- for each transform handle CMatch;
- convert tokens back to a string.

For now, I opted not do do it, because:

- too much changes on a single row;
- docs build time is taking ~3:30 minutes, which is
about the same time it ws taken before the changes;
- there is a very dirty hack inside function_xforms:
(KernRe(r"_noprof"), ""). This is meant to change
function prototypes instead of function arguments.

So, if ok for you, I would prefer to merge this one first. We can later
optimize kdoc_parser to avoid multiple token <-> string conversions.

-

One important aspect of this series is that it introduces unittests
for kernel-doc. I used it a lot during the development of this series,
to ensure that the changes I was doing were producing the expected
results. Tests are on two separate files that can be executed directly.

Alternatively, there is a run.py script that runs all of them (and
any other python script named tools/unittests/test_*.py"):

$ tools/unittests/run.py
test_cmatch:
TestSearch:
test_search_acquires_multiple: OK
test_search_acquires_nested_paren: OK
test_search_acquires_simple: OK
test_search_must_hold: OK
test_search_must_hold_shared: OK
test_search_no_false_positive: OK
test_search_no_function: OK
test_search_no_macro_remains: OK
TestSubMultipleMacros:
test_acquires_multiple: OK
test_acquires_nested_paren: OK
test_acquires_simple: OK
test_mixed_macros: OK
test_must_hold: OK
test_must_hold_shared: OK
test_no_false_positive: OK
test_no_function: OK
test_no_macro_remains: OK
TestSubSimple:
test_rise_early_greedy: OK
test_rise_multiple_greedy: OK
test_strip_multiple_acquires: OK
test_sub_count_parameter: OK
test_sub_mixed_placeholders: OK
test_sub_multiple_placeholders: OK
test_sub_no_placeholder: OK
test_sub_single_placeholder: OK
test_sub_with_capture: OK
test_sub_zero_placeholder: OK
TestSubWithLocalXforms:
test_functions_with_acquires_and_releases: OK
test_raw_struct_group: OK
test_raw_struct_group_tagged: OK
test_struct_group: OK
test_struct_group_attr: OK
test_struct_group_tagged_with_private: OK
test_struct_kcov: OK
test_vars_stackdepot: OK

test_tokenizer:
TestPublicPrivate:
test_balanced_inner_private: OK
test_balanced_non_greddy_private: OK
test_balanced_private: OK
test_no private: OK
test_unbalanced_inner_private: OK
test_unbalanced_private: OK
test_unbalanced_struct_group_tagged_with_private: OK
test_unbalanced_two_struct_group_tagged_first_with_private: OK
test_unbalanced_without_end_of_line: OK
TestTokenizer:
test_basic_tokens: OK
test_depth_counters: OK
test_mismatch_error: OK

Ran 47 tests

PS.: This series contain the contents of the previous /8 series:
https://lore.kernel.org/linux-doc/cover.1773074166.git.mchehab+huawei@kernel.org/

---

v2:
- Added 8 more patches fixing several bugs and modifying unittests
accordingly:
- don't raise exceptions when not needed;
- don't report errors reporting lack of END if there's no BEGIN
at the last replacement string;
- document private scope propagation;
- some changes at unittests to reflect current status;
- addition of two unittests to check error raise logic at c_lex.

Mauro Carvalho Chehab (28):
docs: python: add helpers to run unit tests
unittests: add a testbench to check public/private kdoc comments
docs: kdoc: don't add broken comments inside prototypes
docs: kdoc: properly handle empty enum arguments
docs: kdoc_re: add a C tokenizer
docs: kdoc: use tokenizer to handle comments on structs
docs: kdoc: move C Tokenizer to c_lex module
unittests: test_private: modify it to use CTokenizer directly
unittests: test_tokenizer: check if the tokenizer works
unittests: add a runner to execute all unittests
docs: kdoc: create a CMatch to match nested C blocks
tools: unittests: add tests for CMatch
docs: c_lex: properly implement a sub() method for CMatch
unittests: test_cmatch: add tests for sub()
docs: kdoc: replace NestedMatch with CMatch
docs: kdoc_re: get rid of NestedMatch class
docs: xforms_lists: handle struct_group directly
docs: xforms_lists: better evaluate struct_group macros
docs: c_lex: add support to work with pure name ids
docs: xforms_lists: use CMatch for all identifiers
docs: c_lex: add "@" operator
docs: c_lex: don't exclude an extra token
docs: c_lex: setup a logger to report tokenizer issues
docs: unittests: add and adjust tests to check for errors
docs: c_lex: better handle BEGIN/END at search
docs: kernel-doc.rst: document private: scope propagation
docs: c_lex: produce a cleaner str() representation
unittests: test_cmatch: remove weird stuff from expected results

Documentation/doc-guide/kernel-doc.rst | 6 +
Documentation/tools/python.rst | 2 +
Documentation/tools/unittest.rst | 24 +
tools/lib/python/kdoc/c_lex.py | 645 +++++++++++++++++++
tools/lib/python/kdoc/kdoc_parser.py | 29 +-
tools/lib/python/kdoc/kdoc_re.py | 201 ------
tools/lib/python/kdoc/xforms_lists.py | 209 +++----
tools/lib/python/unittest_helper.py | 353 +++++++++++
tools/unittests/run.py | 17 +
tools/unittests/test_cmatch.py | 821 +++++++++++++++++++++++++
tools/unittests/test_tokenizer.py | 462 ++++++++++++++
11 files changed, 2434 insertions(+), 335 deletions(-)
create mode 100644 Documentation/tools/unittest.rst
create mode 100644 tools/lib/python/kdoc/c_lex.py
create mode 100755 tools/lib/python/unittest_helper.py
create mode 100755 tools/unittests/run.py
create mode 100755 tools/unittests/test_cmatch.py
create mode 100755 tools/unittests/test_tokenizer.py

--
2.52.0