Re: [PULL 03/15] tests/acpi/bios-tables-test: do not write new blobs unless there are changes

[Ani Sinha]

> On 24-Jan-2024, at 14:28, Igor Mammedov <imammedo@redhat.com> wrote:
> 
> On Fri, 1 Dec 2023 12:15:16 -0500
> "Michael S. Tsirkin" <mst@redhat.com> wrote:
> 
>> From: Ani Sinha <anisinha@redhat.com>
>> 
>> When dumping table blobs using rebuild-expected-aml.sh, table blobs from all
>> test variants are dumped regardless of whether there are any actual changes 
>> to
>> the tables or not. This creates lot of new files for various test variants 
>> that
>> are not part of the git repository. This is because we do not check in all 
>> table
>> blobs for all test variants into the repository. Only those blobs for those
>> variants that are different from the generic test-variant agnostic blob are
>> checked in.
>> 
>> This change makes the test smarter by checking if at all there are any 
>> changes
>> in the tables from the checked-in gold master blobs and take actions
>> accordingly.
>> 
>> When there are no changes:
>> - No new table blobs would be written.
>> - Existing table blobs will be refreshed (git diff will show no changes).
>> When there are changes:
>> - New table blob files will be dumped.
>> - Existing table blobs will be refreshed (git diff will show that the files
>>   changed, asl diff will show the actual changes).
> 
>> When new tables are introduced:
>> - Zero byte empty file blobs for new tables as instructed in the header of
>>   bios-tables-test.c will be regenerated to actual table blobs.
> 
> Ani,
> 
> what previously worked is the is there weren't _any_ expected blobs
> (exact match/fallback) found a new table would be dumped.
> So then later 'git status' would show a list of new files.

Yes this was the original complaint from Peter. Lots of new files were 
generated when basically they were identical but differed in naming.

> With this commit it's however not dumping new files files,
> and explodes at
> #5  0x000055555556808e in load_expected_aml (data=0x7fffffffd7b0) at 
> tests/qtest/bios-tables-test.c:414
> #6  0x00005555555676b0 in dump_aml_files (data=0x7fffffffd7b0, rebuild=true) 
> at tests/qtest/bios-tables-test.c:256
> 
> sure it can be worked around by manually creating empty files
> for expected files

Yes this has already been documented in the commit log.

> but if it's a new machine type, one has to create
> a bunch of them basically running multiple iterations of rebuild in V=2
> mode to see what's missing.
> (IMHO cure turned out to be worse than illness)

I don’t know how common it is to create new machines. 

> 
> for reproducing create a test for other than default machine type, ex:
> 
>    test_data data = {                                                         
>   
>        .machine = "pc-i440fx-2.0",                                            
>   
>        .variant = ".pc_legacy",                                               
>                
>    }; 
> 
> 
> is it possible to fix it so that one doesn't have to create empty files 
> manually?
> 
>> 
>> This would make analyzing changes to tables less confusing and there would
>> be no need to clean useless untracked files when there are no table changes.
>> 
>> CC: peter.maydell@linaro.org
>> Signed-off-by: Ani Sinha <anisinha@redhat.com>
>> Message-Id: <20231107044952.5461-1-anisinha@redhat.com>
>> Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
>> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
>> ---
>> tests/qtest/bios-tables-test.c | 14 +++++++++++++-
>> 1 file changed, 13 insertions(+), 1 deletion(-)
>> 
>> diff --git a/tests/qtest/bios-tables-test.c b/tests/qtest/bios-tables-test.c
>> index 71af5cf69f..fe6a9a8563 100644
>> --- a/tests/qtest/bios-tables-test.c
>> +++ b/tests/qtest/bios-tables-test.c
>> @@ -112,6 +112,7 @@ static const char *iasl;
>> #endif
>> 
>> static int verbosity_level;
>> +static GArray *load_expected_aml(test_data *data);
>> 
>> static bool compare_signature(const AcpiSdtTable *sdt, const char *signature)
>> {
>> @@ -244,21 +245,32 @@ static void test_acpi_fadt_table(test_data *data)
>> 
>> static void dump_aml_files(test_data *data, bool rebuild)
>> {
>> -    AcpiSdtTable *sdt;
>> +    AcpiSdtTable *sdt, *exp_sdt;
>>     GError *error = NULL;
>>     gchar *aml_file = NULL;
>> +    test_data exp_data = {};
>>     gint fd;
>>     ssize_t ret;
>>     int i;
>> 
>> +    exp_data.tables = load_expected_aml(data);
>>     for (i = 0; i < data->tables->len; ++i) {
>>         const char *ext = data->variant ? data->variant : "";
>>         sdt = &g_array_index(data->tables, AcpiSdtTable, i);
>> +        exp_sdt = &g_array_index(exp_data.tables, AcpiSdtTable, i);
>>         g_assert(sdt->aml);
>> +        g_assert(exp_sdt->aml);
>> 
>>         if (rebuild) {
>>             aml_file = g_strdup_printf("%s/%s/%.4s%s", data_dir, 
>> data->machine,
>>                                        sdt->aml, ext);
>> +            if (!g_file_test(aml_file, G_FILE_TEST_EXISTS) &&
>> +                sdt->aml_len == exp_sdt->aml_len &&
>> +                !memcmp(sdt->aml, exp_sdt->aml, sdt->aml_len)) {
>> +                /* identical tables, no need to write new files */
>> +                g_free(aml_file);
>> +                continue;
>> +            }
>>             fd = g_open(aml_file, O_WRONLY|O_TRUNC|O_CREAT,
>>                         S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP|S_IROTH);
>>             if (fd < 0) {
>