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

[Igor Mammedov <imammedo@redhat.com>]

On Thu,  2 Nov 2023 13:46:24 +0530
Ani Sinha <anisinha@redhat.com> wrote:

> 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.

> If there are no changes, no new files are written for test variants.
> However, existing files continue to be overwritten regardless of whether there are changes.
> Hence, new files will be generated only when there are actual changes in the tables.

You lost me in those 3 sentences. Perhaps rephrasing and adding examples
wold make it readable. (aka what's (not)writen and when)


> 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.

what happens if an absolutely new table has been introduced which
is not mentioned in tests yet (will it be dumped or not)?

> 
> CC: peter.maydell@linaro.org
> Signed-off-by: Ani Sinha <anisinha@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 9f4bc15aab..743b509e93 100644
> --- a/tests/qtest/bios-tables-test.c
> +++ b/tests/qtest/bios-tables-test.c
> @@ -109,6 +109,7 @@ 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)
>  {
> @@ -241,21 +242,32 @@ 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) {