Improve unreachable subsetting check

CHANGELOG.md

@@ -10,7 +10,8 @@ A more detailed list of changes is available in the corresponding milestones for
 ### Bug Fixes
 #### On the Universal Profile
   - **[com.google.fonts/check/font_is_centered_vertically]:** Fix yet another error on fonts without ASCII letters (issue #4269)
-
+#### On the Google Fonts Profile
+  - **[com.google.fonts/check/metadata/unreachable_subsetting]:** Report codepoints in supplementary Unicode planes, and codepoints with no glyphset support at all (PR #4273)
 
 ## 0.9.1 (2023-Sep-19)
 ### Stable release notes

Lib/fontbakery/profiles/googlefonts.py

@@ -1043,14 +1043,7 @@ def com_google_fonts_check_vendor_id(ttFont, registered_vendor_ids):
 
 @condition
 def font_codepoints(ttFont):
-    codepoints = set()
-    for table in ttFont["cmap"].tables:
-        if (
-            table.platformID == PlatformID.WINDOWS
-            and table.platEncID == WindowsEncodingID.UNICODE_BMP
-        ):
-            codepoints.update(table.cmap.keys())
-    return codepoints
+    return set(ttFont.getBestCmap().keys())
 
 
 @check(
@@ -1166,33 +1159,48 @@ def com_google_fonts_check_metadata_unsupported_subsets(
         will not be served in the subsetted fonts, and so will be unreachable to
         the end user.
     """,
-    conditions=["family_metadata"],
-    proposal="https://github.com/fonttools/fontbakery/issues/4097",
+    proposal=[
+        "https://github.com/fonttools/fontbakery/issues/4097",
+        "https://github.com/fonttools/fontbakery/pull/4273",
+    ],
     severity=2,
 )
 def com_google_fonts_check_metadata_unreachable_subsetting(
-    family_metadata, ttFont, font_codepoints, config
+    family_directory, font, ttFont, font_codepoints, config
 ):
     """Check for codepoints not covered by METADATA subsets."""
     from glyphsets import codepoints
     from fontbakery.utils import pretty_print_list
+    from fontbakery.profiles.googlefonts_conditions import (
+        metadata_file,
+        family_metadata,
+    )
     import unicodedata2
 
     codepoints.set_encoding_path(codepoints.nam_dir)
 
-    for subset in family_metadata.subsets:
+    # Use the METADATA.pb subsets if we have them
+    metadatapb = metadata_file(family_directory)
+    if metadatapb:
+        metadata = family_metadata(metadatapb)
+        if metadata:
+            subsets = metadata.subsets
+        else:
+            yield FAIL, Message(
+                "unparsable-metadata", "Could not parse metadata.pb file"
+            )
+            return
+    else:
+        # Follow what the packager would do
+        subsets = [s[0] for s in codepoints.SubsetsInFont(font, 50, 0.01)]
+
+    for subset in subsets:
         font_codepoints = font_codepoints - set(codepoints.CodepointsInSubset(subset))
 
     if not font_codepoints:
         yield PASS, "OK"
         return
 
-    message = """The following codepoints supported by the font are not covered by
-    any subsets defined in the font's metadata file, and will never
-    be served. You can solve this by either manually adding additional
-    subset declarations to METADATA.pb, or by editing the glyphset
-    definitions.\n\n"""
-
     unreachable = []
     subsets_for_cps = defaultdict(set)
     # This is faster than calling SubsetsForCodepoint for each codepoint
@@ -1202,23 +1210,29 @@ def com_google_fonts_check_metadata_unreachable_subsetting(
             subsets_for_cps[cp].add(subset)
 
     for codepoint in sorted(font_codepoints):
-        subsets = subsets_for_cps[codepoint]
-        if not subsets:
-            continue
+        subsets_for_cp = subsets_for_cps[codepoint]
 
-        if len(subsets) > 1:
-            subsets = "one of: " + ", ".join(subsets)
+        if len(subsets_for_cp) == 0:
+            message = "not included in any glyphset definition"
+        elif len(subsets_for_cp) == 1:
+            message = "try adding " + ", ".join(subsets_for_cp)
         else:
-            subsets = ", ".join(subsets)
+            message = "try adding one of: " + ", ".join(subsets_for_cp)
 
         try:
             name = unicodedata2.name(chr(codepoint))
         except Exception:
             name = ""
 
-        unreachable.append(" * U+%04X %s: try adding %s" % (codepoint, name, subsets))
+        unreachable.append(" * U+%04X %s: %s" % (codepoint, name, message))
+
+    message = """The following codepoints supported by the font are not covered by
+    any subsets defined in the font's metadata file, and will never
+    be served. You can solve this by either manually adding additional
+    subset declarations to METADATA.pb, or by editing the glyphset
+    definitions.\n\n"""
 
-    subsets = ", ".join(f"`{s}`" for s in family_metadata.subsets)
+    subsets = ", ".join(f"`{s}`" for s in subsets)
     message += pretty_print_list(config, unreachable, sep="\n", glue="\n")
     message += (
         f"\n\nOr you can add the above codepoints to one"

setup.py

@@ -158,7 +158,8 @@
     python_requires=">=3.8",
     setup_requires=[
         "setuptools>=61.2",
-        "setuptools_scm[toml]>=6.2",
+        "setuptools_scm[toml]>=6.2, !=8.0.0",  # version 8.0.0 had a bug as described at
+        # https://github.com/pypa/setuptools_scm/issues/905
     ],
     install_requires=[
         # ---

tests/profiles/googlefonts_test.py

@@ -5188,6 +5188,14 @@ def test_check_metadata_unreachable_subsetting():
         check(font), WARN, "unreachable-subsetting", "with a bad font"
     )
 
+    font = TEST_FILE("playfair/Playfair-Italic[opsz,wdth,wght].ttf")
+    assert_results_contain(
+        check(font),
+        WARN,
+        "unreachable-subsetting",
+        "with a bad font and no METADATA.pb",
+    )
+
 
 def test_check_alt_caron():
     """Check accent of Lcaron, dcaron, lcaron, tcaron"""