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[v2,00/19] Adds reftable library code from https://github.com/hanwen/reftable.

Message ID pull.1081.v2.git.git.1631213264.gitgitgadget@gmail.com (mailing list archive)
Headers show
Series Adds reftable library code from https://github.com/hanwen/reftable. | expand

Message

Linus Arver via GitGitGadget Sept. 9, 2021, 6:47 p.m. UTC
The reftable format is described in Documentation/technical/reftable.txt.

This is a fully reentrant implementation of reading and writing the reftable
file format, and should be suitable for embedding in libgit2 too. It does
not hook the code up to git to function as a ref storage backend yet.

v2:

 * fold in OpenBSD fixes by Carlo Belón.

Han-Wen Nienhuys (19):
  hash.h: provide constants for the hash IDs
  reftable: RFC: add LICENSE
  reftable: add error related functionality
  reftable: utility functions
  reftable: add blocksource, an abstraction for random access reads
  reftable: (de)serialization for the polymorphic record type.
  Provide zlib's uncompress2 from compat/zlib-compat.c
  reftable: reading/writing blocks
  reftable: a generic binary tree implementation
  reftable: write reftable files
  reftable: generic interface to tables
  reftable: read reftable files
  reftable: reftable file level tests
  reftable: add a heap-based priority queue for reftable records
  reftable: add merged table view
  reftable: implement refname validation
  reftable: implement stack, a mutable database of reftable files.
  reftable: add dump utility
  Add "test-tool dump-reftable" command.

 Makefile                                   |   53 +-
 ci/lib.sh                                  |    1 +
 compat/.gitattributes                      |    1 +
 compat/zlib-uncompress2.c                  |   95 ++
 config.mak.uname                           |    5 +
 configure.ac                               |   13 +
 contrib/buildsystems/CMakeLists.txt        |   14 +-
 contrib/buildsystems/Generators/Vcxproj.pm |   11 +-
 hash.h                                     |    6 +
 object-file.c                              |    7 +-
 reftable/LICENSE                           |   31 +
 reftable/basics.c                          |  128 ++
 reftable/basics.h                          |   60 +
 reftable/basics_test.c                     |   98 ++
 reftable/block.c                           |  439 ++++++
 reftable/block.h                           |  127 ++
 reftable/block_test.c                      |  120 ++
 reftable/blocksource.c                     |  148 +++
 reftable/blocksource.h                     |   22 +
 reftable/constants.h                       |   21 +
 reftable/dump.c                            |  107 ++
 reftable/error.c                           |   41 +
 reftable/generic.c                         |  169 +++
 reftable/generic.h                         |   32 +
 reftable/iter.c                            |  194 +++
 reftable/iter.h                            |   69 +
 reftable/merged.c                          |  362 +++++
 reftable/merged.h                          |   35 +
 reftable/merged_test.c                     |  292 ++++
 reftable/pq.c                              |  105 ++
 reftable/pq.h                              |   33 +
 reftable/pq_test.c                         |   82 ++
 reftable/publicbasics.c                    |   58 +
 reftable/reader.c                          |  801 +++++++++++
 reftable/reader.h                          |   66 +
 reftable/readwrite_test.c                  |  652 +++++++++
 reftable/record.c                          | 1212 +++++++++++++++++
 reftable/record.h                          |  139 ++
 reftable/record_test.c                     |  412 ++++++
 reftable/refname.c                         |  209 +++
 reftable/refname.h                         |   29 +
 reftable/refname_test.c                    |  102 ++
 reftable/reftable-blocksource.h            |   49 +
 reftable/reftable-error.h                  |   62 +
 reftable/reftable-generic.h                |   47 +
 reftable/reftable-iterator.h               |   39 +
 reftable/reftable-malloc.h                 |   18 +
 reftable/reftable-merged.h                 |   72 +
 reftable/reftable-reader.h                 |  101 ++
 reftable/reftable-record.h                 |  114 ++
 reftable/reftable-stack.h                  |  128 ++
 reftable/reftable-tests.h                  |   23 +
 reftable/reftable-writer.h                 |  148 +++
 reftable/reftable.c                        |  115 ++
 reftable/stack.c                           | 1396 ++++++++++++++++++++
 reftable/stack.h                           |   41 +
 reftable/stack_test.c                      |  949 +++++++++++++
 reftable/system.h                          |   32 +
 reftable/test_framework.c                  |   23 +
 reftable/test_framework.h                  |   53 +
 reftable/tree.c                            |   63 +
 reftable/tree.h                            |   34 +
 reftable/tree_test.c                       |   61 +
 reftable/writer.c                          |  690 ++++++++++
 reftable/writer.h                          |   50 +
 t/helper/test-reftable.c                   |   21 +
 t/helper/test-tool.c                       |    4 +-
 t/helper/test-tool.h                       |    2 +
 t/t0032-reftable-unittest.sh               |   15 +
 69 files changed, 10939 insertions(+), 12 deletions(-)
 create mode 100644 compat/.gitattributes
 create mode 100644 compat/zlib-uncompress2.c
 create mode 100644 reftable/LICENSE
 create mode 100644 reftable/basics.c
 create mode 100644 reftable/basics.h
 create mode 100644 reftable/basics_test.c
 create mode 100644 reftable/block.c
 create mode 100644 reftable/block.h
 create mode 100644 reftable/block_test.c
 create mode 100644 reftable/blocksource.c
 create mode 100644 reftable/blocksource.h
 create mode 100644 reftable/constants.h
 create mode 100644 reftable/dump.c
 create mode 100644 reftable/error.c
 create mode 100644 reftable/generic.c
 create mode 100644 reftable/generic.h
 create mode 100644 reftable/iter.c
 create mode 100644 reftable/iter.h
 create mode 100644 reftable/merged.c
 create mode 100644 reftable/merged.h
 create mode 100644 reftable/merged_test.c
 create mode 100644 reftable/pq.c
 create mode 100644 reftable/pq.h
 create mode 100644 reftable/pq_test.c
 create mode 100644 reftable/publicbasics.c
 create mode 100644 reftable/reader.c
 create mode 100644 reftable/reader.h
 create mode 100644 reftable/readwrite_test.c
 create mode 100644 reftable/record.c
 create mode 100644 reftable/record.h
 create mode 100644 reftable/record_test.c
 create mode 100644 reftable/refname.c
 create mode 100644 reftable/refname.h
 create mode 100644 reftable/refname_test.c
 create mode 100644 reftable/reftable-blocksource.h
 create mode 100644 reftable/reftable-error.h
 create mode 100644 reftable/reftable-generic.h
 create mode 100644 reftable/reftable-iterator.h
 create mode 100644 reftable/reftable-malloc.h
 create mode 100644 reftable/reftable-merged.h
 create mode 100644 reftable/reftable-reader.h
 create mode 100644 reftable/reftable-record.h
 create mode 100644 reftable/reftable-stack.h
 create mode 100644 reftable/reftable-tests.h
 create mode 100644 reftable/reftable-writer.h
 create mode 100644 reftable/reftable.c
 create mode 100644 reftable/stack.c
 create mode 100644 reftable/stack.h
 create mode 100644 reftable/stack_test.c
 create mode 100644 reftable/system.h
 create mode 100644 reftable/test_framework.c
 create mode 100644 reftable/test_framework.h
 create mode 100644 reftable/tree.c
 create mode 100644 reftable/tree.h
 create mode 100644 reftable/tree_test.c
 create mode 100644 reftable/writer.c
 create mode 100644 reftable/writer.h
 create mode 100644 t/helper/test-reftable.c
 create mode 100755 t/t0032-reftable-unittest.sh


base-commit: e0a2f5cbc585657e757385ad918f167f519cfb96
Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-git-1081%2Fhanwen%2Fjust-library-v2
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-git-1081/hanwen/just-library-v2
Pull-Request: https://github.com/git/git/pull/1081

Range-diff vs v1:

  1:  b9ee8cd8e9f =  1:  8534c69cf84 hash.h: provide constants for the hash IDs
  2:  2d31c783fb5 =  2:  52968d8e83f reftable: RFC: add LICENSE
  3:  ea6f4f8c150 =  3:  84c8b396df5 reftable: add error related functionality
  4:  fd5c5c9f338 !  4:  fa58f3d73e7 reftable: utility functions
     @@ Makefile: OBJECTS += $(PROGRAM_OBJS)
       endif
      @@ Makefile: $(LIB_FILE): $(LIB_OBJS)
       $(XDIFF_LIB): $(XDIFF_OBJS)
     - 	$(QUIET_AR)$(AR) $(ARFLAGS) $@ $^
     + 	$(QUIET_AR)$(RM) $@ && $(AR) $(ARFLAGS) $@ $^
       
      +$(REFTABLE_LIB): $(REFTABLE_OBJS)
      +	$(QUIET_AR)$(RM) $@ && $(AR) $(ARFLAGS) $@ $^
     @@ reftable/system.h (new)
      +
      +#include <zlib.h>
      +
     -+struct strbuf;
     ++#ifdef NO_UNCOMPRESS2
     ++/*
     ++ * This is uncompress2, which is only available in zlib >= 1.2.9
     ++ * (released as of early 2017)
     ++ */
     ++int uncompress2(Bytef *dest, uLongf *destLen, const Bytef *source,
     ++		uLong *sourceLen);
     ++#endif
     ++
      +int hash_size(uint32_t id);
      +
      +#endif
  5:  c11f06ed6fb =  5:  e9206532126 reftable: add blocksource, an abstraction for random access reads
  6:  23977331cf8 =  6:  651e195fe77 reftable: (de)serialization for the polymorphic record type.
  7:  aa9b8e05dbd !  7:  e595dbc6c84 Provide zlib's uncompress2 from compat/zlib-compat.c
     @@ compat/zlib-uncompress2.c (new)
      +
      +*/
      +
     ++#include "../reftable/system.h"
     ++#define z_const
     ++
      +/*
      + * Copyright (C) 1995-2003, 2010, 2014, 2016 Jean-loup Gailly, Mark Adler
      + * For conditions of distribution and use, see copyright notice in zlib.h
     @@ config.mak.uname: ifeq ($(uname_S),FreeBSD)
       endif
       ifeq ($(uname_S),OpenBSD)
      +	NO_UNCOMPRESS2 = YesPlease
     ++	# Versions < 7.0 need compatibility layer
     ++	ifeq ($(shell expr "$(uname_R)" : "[1-6]\."),2)
     ++		NO_UNCOMPRESS2 = UnfortunatelyYes
     ++	endif
       	NO_STRCASESTR = YesPlease
       	NO_MEMMEM = YesPlease
       	USE_ST_TIMESPEC = YesPlease
  8:  2648e05c510 !  8:  97f7ee04886 reftable: reading/writing blocks
     @@ reftable/block.c (new)
      +#include "system.h"
      +#include <zlib.h>
      +
     -+#ifdef NO_UNCOMPRESS2
     -+/*
     -+ * This is uncompress2, which is only available in zlib >= 1.2.9
     -+ * (released as of early 2017)
     -+ */
     -+int uncompress2(Bytef *dest, uLongf *destLen, const Bytef *source,
     -+		uLong *sourceLen);
     -+#endif
     -+
      +int header_size(int version)
      +{
      +	switch (version) {
  9:  49a9a00465d !  9:  8d2e8be5795 reftable: a generic binary tree implementation
     @@ reftable/tree_test.c (new)
      +{
      +	struct curry *c = arg;
      +	if (c->last) {
     -+		assert(test_compare(c->last, key) < 0);
     ++		EXPECT(test_compare(c->last, key) < 0);
      +	}
      +	c->last = key;
      +}
     @@ reftable/tree_test.c (new)
      +	} while (i != 1);
      +
      +	for (i = 1; i < ARRAY_SIZE(nodes); i++) {
     -+		assert(values + i == nodes[i]->key);
     -+		assert(nodes[i] ==
     ++		EXPECT(values + i == nodes[i]->key);
     ++		EXPECT(nodes[i] ==
      +		       tree_search(values + i, &root, &test_compare, 0));
      +	}
      +
 10:  c00876afd26 = 10:  965af6ec065 reftable: write reftable files
 11:  0f32d6f4c91 = 11:  4e259380fda reftable: generic interface to tables
 12:  a77878993aa = 12:  a43d3512164 reftable: read reftable files
 13:  4bbefe977ae = 13:  f0e159cd853 reftable: reftable file level tests
 14:  7ee46496081 ! 14:  5a5c108d601 reftable: add a heap-based priority queue for reftable records
     @@ reftable/pq.c (new)
      +#include "system.h"
      +#include "basics.h"
      +
     -+static int pq_less(struct pq_entry a, struct pq_entry b)
     ++int pq_less(struct pq_entry *a, struct pq_entry *b)
      +{
      +	struct strbuf ak = STRBUF_INIT;
      +	struct strbuf bk = STRBUF_INIT;
      +	int cmp = 0;
     -+	reftable_record_key(&a.rec, &ak);
     -+	reftable_record_key(&b.rec, &bk);
     ++	reftable_record_key(&a->rec, &ak);
     ++	reftable_record_key(&b->rec, &bk);
      +
      +	cmp = strbuf_cmp(&ak, &bk);
      +
     @@ reftable/pq.c (new)
      +	strbuf_release(&bk);
      +
      +	if (cmp == 0)
     -+		return a.index > b.index;
     ++		return a->index > b->index;
      +
      +	return cmp < 0;
      +}
     @@ reftable/pq.c (new)
      +	return pq.len == 0;
      +}
      +
     -+void merged_iter_pqueue_check(struct merged_iter_pqueue pq)
     -+{
     -+	int i = 0;
     -+	for (i = 1; i < pq.len; i++) {
     -+		int parent = (i - 1) / 2;
     -+
     -+		assert(pq_less(pq.heap[parent], pq.heap[i]));
     -+	}
     -+}
     -+
      +struct pq_entry merged_iter_pqueue_remove(struct merged_iter_pqueue *pq)
      +{
      +	int i = 0;
     @@ reftable/pq.c (new)
      +		int min = i;
      +		int j = 2 * i + 1;
      +		int k = 2 * i + 2;
     -+		if (j < pq->len && pq_less(pq->heap[j], pq->heap[i])) {
     ++		if (j < pq->len && pq_less(&pq->heap[j], &pq->heap[i])) {
      +			min = j;
      +		}
     -+		if (k < pq->len && pq_less(pq->heap[k], pq->heap[min])) {
     ++		if (k < pq->len && pq_less(&pq->heap[k], &pq->heap[min])) {
      +			min = k;
      +		}
      +
     @@ reftable/pq.c (new)
      +	i = pq->len - 1;
      +	while (i > 0) {
      +		int j = (i - 1) / 2;
     -+		if (pq_less(pq->heap[j], pq->heap[i])) {
     ++		if (pq_less(&pq->heap[j], &pq->heap[i])) {
      +			break;
      +		}
      +
     @@ reftable/pq.h (new)
      +struct pq_entry merged_iter_pqueue_remove(struct merged_iter_pqueue *pq);
      +void merged_iter_pqueue_add(struct merged_iter_pqueue *pq, struct pq_entry e);
      +void merged_iter_pqueue_release(struct merged_iter_pqueue *pq);
     ++int pq_less(struct pq_entry *a, struct pq_entry *b);
      +
      +#endif
      
     @@ reftable/pq_test.c (new)
      +#include "reftable-tests.h"
      +#include "test_framework.h"
      +
     ++void merged_iter_pqueue_check(struct merged_iter_pqueue pq)
     ++{
     ++	int i = 0;
     ++	for (i = 1; i < pq.len; i++) {
     ++		int parent = (i - 1) / 2;
     ++
     ++		assert(pq_less(&pq.heap[parent], &pq.heap[i]));
     ++	}
     ++}
     ++
      +static void test_pq(void)
      +{
      +	char *names[54] = { NULL };
     @@ reftable/pq_test.c (new)
      +		merged_iter_pqueue_check(pq);
      +
      +		if (last) {
     -+			assert(strcmp(last, ref->refname) < 0);
     ++			EXPECT(strcmp(last, ref->refname) < 0);
      +		}
      +		last = ref->refname;
      +		ref->refname = NULL;
 15:  8bc889aaae8 ! 15:  905ffa58f36 reftable: add merged table view
     @@ reftable/merged_test.c (new)
      +	for (i = 0; i < n; i++) {
      +		uint64_t before = refs[i].update_index;
      +		int n = reftable_writer_add_ref(w, &refs[i]);
     -+		assert(n == 0);
     -+		assert(before == refs[i].update_index);
     ++		EXPECT(n == 0);
     ++		EXPECT(before == refs[i].update_index);
      +	}
      +
      +	err = reftable_writer_close(w);
     @@ reftable/merged_test.c (new)
      +	}
      +	reftable_iterator_destroy(&it);
      +
     -+	assert(ARRAY_SIZE(want) == len);
     ++	EXPECT(ARRAY_SIZE(want) == len);
      +	for (i = 0; i < len; i++) {
     -+		assert(reftable_ref_record_equal(&want[i], &out[i],
     ++		EXPECT(reftable_ref_record_equal(&want[i], &out[i],
      +						 GIT_SHA1_RAWSZ));
      +	}
      +	for (i = 0; i < len; i++) {
     @@ reftable/merged_test.c (new)
      +	EXPECT_ERR(err);
      +
      +	hash_id = reftable_reader_hash_id(rd);
     -+	assert(hash_id == GIT_SHA1_FORMAT_ID);
     ++	EXPECT(hash_id == GIT_SHA1_FORMAT_ID);
      +
      +	reftable_table_from_reader(&tab[0], rd);
      +	err = reftable_new_merged_table(&merged, tab, 1, GIT_SHA1_FORMAT_ID);
 16:  9a30c1c4666 = 16:  e9598889af2 reftable: implement refname validation
 17:  b099c42d65d = 17:  8b0ee68c636 reftable: implement stack, a mutable database of reftable files.
 18:  0170f20b5e7 = 18:  a9bebe45bde reftable: add dump utility
 19:  4fc6b5cbf16 = 19:  104fbc7502f Add "test-tool dump-reftable" command.

Comments

Junio C Hamano Sept. 9, 2021, 8:02 p.m. UTC | #1
"Han-Wen Nienhuys via GitGitGadget" <gitgitgadget@gmail.com> writes:

> The reftable format is described in Documentation/technical/reftable.txt.
>
> This is a fully reentrant implementation of reading and writing the reftable
> file format, and should be suitable for embedding in libgit2 too. It does
> not hook the code up to git to function as a ref storage backend yet.
>
> v2:
>
>  * fold in OpenBSD fixes by Carlo Belón.

Thanks, both.  Will replace.
Junio C Hamano Sept. 9, 2021, 8:32 p.m. UTC | #2
"Han-Wen Nienhuys via GitGitGadget" <gitgitgadget@gmail.com> writes:

> The reftable format is described in Documentation/technical/reftable.txt.
>
> This is a fully reentrant implementation of reading and writing the reftable
> file format, and should be suitable for embedding in libgit2 too. It does
> not hook the code up to git to function as a ref storage backend yet.

Not a question for Han-Wen, but I am wondering how much style and
other consistency guidelines we have in our C code to the files in
this directory.  

I am guessing that rules like "no decl after statement" and "no decl
in the set-up part of the for loop control" (i.e. "for (int i = 0;
..."  is a no-no) should apply equally to this code, but it might be
OK to deviate from rules that are only meant to help human readers [*]
without affecting compilation.

Opinions?


[Footnote]

 * multi-line comment style.

 * asterisk sticks to identifier not to type

 * not enclosing a single-statement block inside {}

 * empty statement looks like

	; /* empty */
Han-Wen Nienhuys Sept. 13, 2021, 10:14 a.m. UTC | #3
On Thu, Sep 9, 2021 at 10:32 PM Junio C Hamano <gitster@pobox.com> wrote:
>
> "Han-Wen Nienhuys via GitGitGadget" <gitgitgadget@gmail.com> writes:
>
> > The reftable format is described in Documentation/technical/reftable.txt.
> >
> > This is a fully reentrant implementation of reading and writing the reftable
> > file format, and should be suitable for embedding in libgit2 too. It does
> > not hook the code up to git to function as a ref storage backend yet.
>
> Not a question for Han-Wen, but I am wondering how much style and
> other consistency guidelines we have in our C code to the files in
> this directory.

I am Han-Wen, but I'm not sure what you are saying here.

> I am guessing that rules like "no decl after statement" and "no decl
> in the set-up part of the for loop control" (i.e. "for (int i = 0;
> ..."  is a no-no) should apply equally to this code, but it might be
> OK to deviate from rules that are only meant to help human readers [*]
> without affecting compilation.
>
> Opinions?

The code has a different style because I wrote it separately from Git.
I'm not wedded to its current style, and most styling can easily be
changed. If you have specific things that should be addressed, let me
know.
Junio C Hamano Sept. 13, 2021, 6:30 p.m. UTC | #4
Han-Wen Nienhuys <hanwen@google.com> writes:

> On Thu, Sep 9, 2021 at 10:32 PM Junio C Hamano <gitster@pobox.com> wrote:
>>
>> "Han-Wen Nienhuys via GitGitGadget" <gitgitgadget@gmail.com> writes:
>>
>> > The reftable format is described in Documentation/technical/reftable.txt.
>> >
>> > This is a fully reentrant implementation of reading and writing the reftable
>> > file format, and should be suitable for embedding in libgit2 too. It does
>> > not hook the code up to git to function as a ref storage backend yet.
>>
>> Not a question for Han-Wen, but I am wondering how much style and
>> other consistency guidelines we have in our C code to the files in
>> this directory.
>
> I am Han-Wen, but I'm not sure what you are saying here.

Sorry, the sentence is unreadable because I missed a verb above
(insert "should apply" between "code" and "to").  

I was asking for opinions on how we should treat this piece of code.
We loosen "style guidelines" on borrowed code that is maintained
elsewhere to ease re-importing, but code we maintain in-tree are
subject to our style guide.  I am not sure how this part that is
meant to be reusable in other projects like libgit2 should be
treated.

>> I am guessing that rules like "no decl after statement" and "no decl
>> in the set-up part of the for loop control" (i.e. "for (int i = 0;
>> ..."  is a no-no) should apply equally to this code, but it might be
>> OK to deviate from rules that are only meant to help human readers [*]
>> without affecting compilation.
>>
>> Opinions?
>
> The code has a different style because I wrote it separately from Git.
> I'm not wedded to its current style, and most styling can easily be
> changed. If you have specific things that should be addressed, let me
> know.

The question was for other reviewers to help us come up with what
the "specific things" ought to be.  I saw style differences around
comments and code formatting (everything I listed in the footnote,
plus, // comment which I forgot to mention) which may or may not
turn out to be part of that "specific things", because they do not
break compilation.
Carlo Marcelo Arenas Belón Sept. 13, 2021, 7:29 p.m. UTC | #5
On Mon, Sep 13, 2021 at 11:30 AM Junio C Hamano <gitster@pobox.com> wrote:
> Han-Wen Nienhuys <hanwen@google.com> writes:
> > The code has a different style because I wrote it separately from Git.
> > I'm not wedded to its current style, and most styling can easily be
> > changed. If you have specific things that should be addressed, let me
> > know.
>
> The question was for other reviewers to help us come up with what
> the "specific things" ought to be.  I saw style differences around
> comments and code formatting (everything I listed in the footnote,
> plus, // comment which I forgot to mention) which may or may not
> turn out to be part of that "specific things", because they do not
> break compilation.

they will be flagged by the compiler in pedantic mode when in gnu89 mode though

  reftable/stack_test.c:49:1: warning: C++ style comments are not
allowed in ISO C
90
     49 | // Work linenumber into the tempdir, so we can see which
tests forget to
        | ^
  reftable/stack_test.c:49:1: note: (this will be reported only once
per input file)

and are probably an easy thing to fix

Carlo
Junio C Hamano Sept. 13, 2021, 8:34 p.m. UTC | #6
Carlo Arenas <carenas@gmail.com> writes:

> On Mon, Sep 13, 2021 at 11:30 AM Junio C Hamano <gitster@pobox.com> wrote:
>> Han-Wen Nienhuys <hanwen@google.com> writes:
>> > The code has a different style because I wrote it separately from Git.
>> > I'm not wedded to its current style, and most styling can easily be
>> > changed. If you have specific things that should be addressed, let me
>> > know.
>>
>> The question was for other reviewers to help us come up with what
>> the "specific things" ought to be.  I saw style differences around
>> comments and code formatting (everything I listed in the footnote,
>> plus, // comment which I forgot to mention) which may or may not
>> turn out to be part of that "specific things", because they do not
>> break compilation.
>
> they will be flagged by the compiler in pedantic mode when in gnu89 mode though
>
>   reftable/stack_test.c:49:1: warning: C++ style comments are not
> allowed in ISO C
> 90
>      49 | // Work linenumber into the tempdir, so we can see which
> tests forget to
>         | ^
>   reftable/stack_test.c:49:1: note: (this will be reported only once
> per input file)
>
> and are probably an easy thing to fix

I guess I still wasn't clear enough, then.  Of course, there is no
question that we do not tolerate compilation-breaking deviation from
our coding guidelines.  The "loosening" exception I was alluding to
were those rules that do not break compilation but help human readers
due to consistent writing.  I do not think

    /* this comment
     * goes against our house style */
    int* a, b;

would be flagged by the gnu89 compiler, for example.