new check: com.adobe.fonts/check/cff_deprecated_operators

on the adobefonts profile
(PR #3033)

CHANGELOG.md

@@ -1,17 +1,18 @@
 Below are the most important changes from each release.
 A more detailed list of changes is available in the corresponding milestones for each release in the Github issue tracker (https://github.com/googlefonts/fontbakery/milestones?state=closed).
 
-## 0.7.31 (2020-Sep-??)
-### Note-worthy code changes
-  - Renamed `multiprocessing.py` to `multiproc.py` to avoid conflict with Python
-    stdlib module of the same name in some configurations.
-
-## 0.7.30 (2020-Aug-??)
+## 0.7.30 (2020-Sept-someday)
 ### Note-worthy code changes
   - Adopted 4-spaces indentation. We're changing our codestyle to facilitate collaboration from people who also work with the fontTools and AFDKO codebases. (issue 2997)
   - All rationale text needs to have 8 indentation spaces (because this indentation on the source should not show up on the user-interface when rationale text is printed on the text terminal)
   - Remove PriorityLevel class as it makes classifying checks by priority more complicated then necessary! (issue #2981)
   - Use the http://fonts.google.com/metadata/fonts endpoint to determine if a font is listed in Google Fonts. (issue #2991)
+  - Renamed `multiprocessing.py` to `multiproc.py` to avoid conflict with Python
+    stdlib module of the same name in some configurations.
+  - Re-worked `cff.py` checks using `@condition` to avoid repeated iterations
+    over the glyph set.
+  - Added checks for deprecated CFF operator `dotsection` and deprecated use of
+    `endchar` operator to build accented characters (`seac`).
 
 ### New Checks
   - **[com.google.fonts/check/varfont_duplicate_instance_names]**: Avoid duplicate instance names in variable fonts (issue #2986)

Lib/fontbakery/profiles/cff.py

@@ -1,5 +1,5 @@
-from fontbakery.callable import check
-from fontbakery.checkrunner import FAIL, PASS
+from fontbakery.callable import check, condition
+from fontbakery.checkrunner import FAIL, PASS, WARN
 from fontbakery.message import Message
 
 # used to inform get_module_profile whether and how to create a profile
@@ -9,6 +9,13 @@
     ('.shared_conditions', ('is_cff', 'is_cff2'))
 ]
 
+class CFFAnalysis:
+    def __init__(self):
+        self.glyphs_dotsection = []
+        self.glyphs_endchar_seac = []
+        self.glyphs_exceed_max = []
+        self.glyphs_recursion_errors = []
+
 def _get_subr_bias(count):
     if count < 1240:
         bias = 107
@@ -32,6 +39,11 @@ def _traverse_subr_call_tree(info, program, depth):
     if depth > 10:
         return
 
+    if len(program) >=5 and program[-1] == 'endchar' and all([isinstance(a, int) for a in program[-5:-1]]):
+        info['saw_endchar_seac'] = True
+    if 'ignore' in program:  # decompiler expresses 'dotsection' as 'ignore'
+        info['saw_dotsection'] = True
+
     while program:
         x = program.pop()
         if x == 'callgsubr':
@@ -44,9 +56,8 @@ def _traverse_subr_call_tree(info, program, depth):
             _traverse_subr_call_tree(info, sub_program, depth + 1)
 
 
-def _check_call_depth(top_dict, private_dict, fd_index=0):
+def _analyze_cff(analysis, top_dict, private_dict, fd_index=0):
     char_strings = top_dict.CharStrings
-
     global_subrs = top_dict.GlobalSubrs
     gsubr_bias = _get_subr_bias(len(global_subrs))
 
@@ -58,7 +69,7 @@ def _check_call_depth(top_dict, private_dict, fd_index=0):
         subr_bias = None
 
     char_list = char_strings.keys()
-    failed = False
+
     for glyph_name in char_list:
         t2_char_string, fd_select_index = char_strings.getItemAndSelector(
             glyph_name)
@@ -67,11 +78,7 @@ def _check_call_depth(top_dict, private_dict, fd_index=0):
         try:
             t2_char_string.decompile()
         except RecursionError:
-            yield FAIL,\
-                  Message("recursion-error",
-                          f'Recursion error while decompiling'
-                          f' glyph "{glyph_name}".')
-            failed = True
+            analysis.glyphs_recursion_errors.append(glyph_name)
             continue
         info = dict()
         info['subrs'] = subrs
@@ -83,70 +90,131 @@ def _check_call_depth(top_dict, private_dict, fd_index=0):
         program = t2_char_string.program.copy()
         _traverse_subr_call_tree(info, program, depth)
         max_depth = info['max_depth']
+
         if max_depth > 10:
-            yield FAIL,\
-                  Message("max-depth",
-                          f'Subroutine call depth exceeded'
-                          f' maximum of 10 for glyph "{glyph_name}".')
-            failed = True
-    return failed
+            analysis.glyphs_exceed_max.append(glyph_name)
+        if info.get('saw_endchar_seac'):
+            analysis.glyphs_endchar_seac.append(glyph_name)
+        if info.get('saw_dotsection'):
+            analysis.glyphs_dotsection.append(glyph_name)
+
+@condition
+def cff_analysis(ttFont):
+
+    analysis = CFFAnalysis()
+
+    if 'CFF ' in ttFont:
+        cff = ttFont['CFF '].cff
+
+        for top_dict in cff.topDictIndex:
+            if hasattr(top_dict, 'FDArray'):
+                for fd_index, font_dict in enumerate(top_dict.FDArray):
+                    if hasattr(font_dict, 'Private'):
+                        private_dict = font_dict.Private
+                    else:
+                        private_dict = None
+                    _analyze_cff(analysis, top_dict, private_dict, fd_index)
+            else:
+                if hasattr(top_dict, 'Private'):
+                    private_dict = top_dict.Private
+                else:
+                    private_dict = None
+                _analyze_cff(analysis, top_dict, private_dict)
 
+    elif 'CFF2' in ttFont:
+        cff = ttFont['CFF2'].cff
+
+        for top_dict in cff.topDictIndex:
+            for fd_index, font_dict in enumerate(top_dict.FDArray):
+                if hasattr(font_dict, 'Private'):
+                    private_dict = font_dict.Private
+                else:
+                    private_dict = None
+                _analyze_cff(analysis, top_dict, private_dict, fd_index)
+
+    return analysis
 
 @check(
     id = 'com.adobe.fonts/check/cff_call_depth',
-    conditions = ['is_cff'],
+    conditions = ['ttFont', 'is_cff', 'cff_analysis'],
     rationale = """
         Per "The Type 2 Charstring Format, Technical Note #5177", the "Subr nesting, stack limit" is 10.
     """
 )
-def com_adobe_fonts_check_cff_call_depth(ttFont):
+def com_adobe_fonts_check_cff_call_depth(cff_analysis):
     """Is the CFF subr/gsubr call depth > 10?"""
+
     any_failures = False
-    cff = ttFont['CFF '].cff
 
-    for top_dict in cff.topDictIndex:
-        if hasattr(top_dict, 'FDArray'):
-            for fd_index, font_dict in enumerate(top_dict.FDArray):
-                if hasattr(font_dict, 'Private'):
-                    private_dict = font_dict.Private
-                else:
-                    private_dict = None
-                failed = yield from \
-                    _check_call_depth(top_dict, private_dict, fd_index)
-                any_failures = any_failures or failed
-        else:
-            if hasattr(top_dict, 'Private'):
-                private_dict = top_dict.Private
-            else:
-                private_dict = None
-            failed = yield from _check_call_depth(top_dict, private_dict)
-            any_failures = any_failures or failed
+    if cff_analysis.glyphs_exceed_max or cff_analysis.glyphs_recursion_errors:
+        any_failures = True
+        for gn in cff_analysis.glyphs_exceed_max:
+            yield FAIL, \
+                  Message('max-depth',
+                          f'Subroutine call depth exceeded maximum of 10 for glyph "{gn}".')
+        for gn in cff_analysis.glyphs_recursion_errors:
+            yield FAIL, \
+                  Message('recursion-error',
+                          f'Recursion error while decompiling glyph "{gn}".')
 
     if not any_failures:
         yield PASS, 'Maximum call depth not exceeded.'
 
 
 @check(
     id = 'com.adobe.fonts/check/cff2_call_depth',
-    conditions = ['is_cff2'],
+    conditions = ['ttFont', 'is_cff2', 'cff_analysis'],
     rationale = """
         Per "The CFF2 CharString Format", the "Subr nesting, stack limit" is 10.
     """
 )
-def com_adobe_fonts_check_cff2_call_depth(ttFont):
+def com_adobe_fonts_check_cff2_call_depth(cff_analysis):
     """Is the CFF2 subr/gsubr call depth > 10?"""
+
     any_failures = False
-    cff = ttFont['CFF2'].cff
 
-    for top_dict in cff.topDictIndex:
-        for fd_index, font_dict in enumerate(top_dict.FDArray):
-            if hasattr(font_dict, 'Private'):
-                private_dict = font_dict.Private
-            else:
-                private_dict = None
-            failed = yield from \
-                _check_call_depth(top_dict, private_dict, fd_index)
-            any_failures = any_failures or failed
+    if cff_analysis.glyphs_exceed_max or cff_analysis.glyphs_recursion_errors:
+        any_failures = True
+        for gn in cff_analysis.glyphs_exceed_max:
+            yield FAIL, \
+                  Message('max-depth',
+                          f'Subroutine call depth exceeded maximum of 10 for glyph "{gn}".')
+        for gn in cff_analysis.glyphs_recursion_errors:
+            yield FAIL, \
+                  Message('recursion-error',
+                          f'Recursion error while decompiling glyph "{gn}".')
 
     if not any_failures:
         yield PASS, 'Maximum call depth not exceeded.'
+
+
+@check(
+    id = 'com.adobe.fonts/check/cff_deprecated_operators',
+    conditions = ['ttFont', 'is_cff', 'cff_analysis'],
+    rationale = """
+        The 'dotsection' operator and the use of 'endchar' to build accented
+        characters from the Adobe Standard Encoding Character Set ("seac") are
+        deprecated in CFF. Adobe recommends repairing any fonts that use these,
+        especially endchar-as-seac, because a rendering issue was discovered in
+        Microsoft Word with a font that makes use of this operation. The check
+        treats that useage as a FAIL. There are no known ill effects of using
+        dotsection, so that check is a WARN.
+    """
+)
+def com_adobe_fonts_check_cff_deprecated_operators(cff_analysis):
+    """Does the font use deprecated CFF operators or operations?"""
+    any_failures = False
+
+    if cff_analysis.glyphs_dotsection or cff_analysis.glyphs_endchar_seac:
+        any_failures = True
+        for gn in cff_analysis.glyphs_dotsection:
+            yield WARN, \
+                  Message('deprecated-operator-dotsection',
+                          f'Glyph "{gn}" uses deprecated "dotsection" operator.')
+        for gn in cff_analysis.glyphs_endchar_seac:
+            yield FAIL, \
+                  Message('deprecated-operation-endchar-seac',
+                          f'Glyph "{gn}" has deprecated use of "endchar" operator to build accented characters (seac).')
+
+    if not any_failures:
+        yield PASS, 'No deprecated CFF operators used.'

Lib/fontbakery/profiles/opentype.py

@@ -52,6 +52,7 @@
     'com.google.fonts/check/loca/maxp_num_glyphs',
     'com.adobe.fonts/check/cff2_call_depth',
     'com.adobe.fonts/check/cff_call_depth',
+    'com.adobe.fonts/check/cff_deprecated_operators',
     'com.google.fonts/check/font_version',
     'com.google.fonts/check/post_table_version',
     'com.google.fonts/check/monospace',

tests/profiles/cff_test.py

@@ -21,7 +21,7 @@ def test_check_cff_call_depth():
     # in this font, glyphs D & E exceed max call depth,
     # and glyph F calls a subroutine that calls itself
     font = TEST_FILE('subr_test_fonts/subr_test_font_infinite_recursion.otf')
-    
+
     assert_results_contain(check(font),
                            FAIL, 'max-depth',
                            '- Subroutine call depth exceeded'
@@ -62,3 +62,20 @@ def test_check_cff2_call_depth():
     assert_results_contain(check(font),
                            FAIL, 'recursion-error',
                            'Recursion error while decompiling glyph "F".')
+
+
+def test_check_cff_deprecated_operators():
+    check = TestingContext(cff_profile,
+                           "com.adobe.fonts/check/cff_deprecated_operators")
+
+    # this font uses the deprecated 'dotsection' operator
+    font = TEST_FILE('deprecated_operators/cff1_dotsection.otf')
+    assert_results_contain(check(font),
+                           WARN, 'deprecated-operator-dotsection',
+                           'Glyph "i" uses deprecated "dotsection" operator.')
+
+    # this font uses the 'endchar' operator in a manner that is deprecated ("seac")
+    font = TEST_FILE('deprecated_operators/cff1_endchar_seac.otf')
+    assert_results_contain(check(font),
+                           FAIL, 'deprecated-operation-endchar-seac',
+                           'Glyph "Agrave" has deprecated use of "endchar" operator to build accented characters (seac).')