Should handle upper-case checksums

[hadess]

Using flatpak-builder as available today on Flathub

The following source snippet:

      # OpenMeshCraft
      # https://github.com/bambulab/BambuStudio/blob/master/deps/OpenMeshCraft/OpenMeshCraft.cmake
      - type: file
        url: https://github.com/bambulab/OpenMeshCraft/archive/0e8d12c3df54804393593ab5d86c05caa340cbee.zip
        dest: external-packages/OpenMeshCraft
        sha256: 632CD806CE932D6A1D76DF0E86ECF8BFC22480E76F80A638A28474F5262E2B9E

generates the following error:

Failed to download sources: module BambuStudio: Wrong sha256 checksum for 0e8d12c3df54804393593ab5d86c05caa340cbee.zip, expected "632CD806CE932D6A1D76DF0E86ECF8BFC22480E76F80A638A28474F5262E2B9E", was "632cd806ce932d6a1d76df0e86ecf8bfc22480e76f80a638a28474f5262e2b9e"

I think that flatpak-builder should probably compare checksums case insensitively. Maybe something like this?

diff --git a/src/builder-utils.c b/src/builder-utils.c
index c0f383a7a798..1d647d137c3b 100644
--- a/src/builder-utils.c
+++ b/src/builder-utils.c
@@ -1220,13 +1220,15 @@ compare_checksum (const char *name,
 {
   const char *type_names[] = { "md5", "sha1", "sha256", "sha512", "sha384" }; /* In GChecksumType order */
   const char *type_name;
+  guint len;
 
   if (checksum_type < G_N_ELEMENTS (type_names))
     type_name = type_names[checksum_type];
   else
     type_name = "unknown";
 
-  if (strcmp (expected_checksum, measured_checksum) != 0)
+  len = MIN(strlen(expected_checksum), strlen(measured_checksum));
+  if (g_ascii_strncasecmp (expected_checksum, measured_checksum, len) != 0)
     {   
       g_set_error (error, G_IO_ERROR, G_IO_ERROR_FAILED,
                    "Wrong %s checksum for %s, expected \"%s\", was \"%s\"", type_name, name,

[bbhtt]

Makes sense would be nice to have a PR plus one test.