Improve wording about new install method

Display informative message when users forget to install the `extra` needed for the vendor-specific profile they're trying to run
(issue fonttools#4292)

CHANGELOG.md

@@ -6,6 +6,8 @@ A more detailed list of changes is available in the corresponding milestones for
 ### Release notes
   - This release adds support for marking checks as **experimental**, which will make them not affect the process exit code and so will allow such checks to result in a FAIL without breaking continuous integration builds. This will give time for users to report problems on the implementation of new checks. If after some time nobody complains, then those new checks will more safely be made effective by removing their `experimental` tag.
 
+  - **Bugfix:** Display informative message when users forget to install the `extra` needed for the vendor-specific profile they're trying to run (issue #4292)
+
 ### New checks
 #### Addded to the Google Fonts Profile
   - **EXPERIMENTAL - [com.google.fonts/check/metadata/empty_designer]:** Any font published on Google Fonts must credit one or several authors, foundry and/or individuals. (issue #3961)

Lib/fontbakery/profiles/googlefonts.py

@@ -26,6 +26,11 @@
 )
 from fontbakery.utils import exit_with_install_instructions
 
+try:
+    from axisregistry import build_filename
+except ImportError:
+    exit_with_install_instructions("googlefonts")
+
 profile_imports = (
     (".", ("googlefonts_conditions", "universal", "outline", "shaping", "ufo_sources")),
 )
@@ -254,13 +259,8 @@
 )
 def com_google_fonts_check_canonical_filename(ttFont):
     """Checking file is named canonically."""
-    try:
-        from axisregistry import build_filename
-
-        current_filename = os.path.basename(ttFont.reader.file.name)
-        expected_filename = build_filename(ttFont)
-    except ImportError:
-        exit_with_install_instructions("googlefonts")
+    current_filename = os.path.basename(ttFont.reader.file.name)
+    expected_filename = build_filename(ttFont)
 
     if current_filename != expected_filename:
         yield FAIL, Message(

Lib/fontbakery/profiles/shaping.py

@@ -27,6 +27,10 @@
 from fontbakery.section import Section
 from fontbakery.utils import exit_with_install_instructions
 
+try:
+    from vharfbuzz import Vharfbuzz
+except ImportError:
+    exit_with_install_instructions("shaping")
 
 shaping_basedir = Path("qa", "shaping_tests")
 
@@ -152,13 +156,8 @@ def get_shaping_parameters(test, configuration):
 def run_a_set_of_shaping_tests(
     config, ttFont, run_a_test, test_filter, generate_report, preparation=None
 ):
-    try:
-        from vharfbuzz import Vharfbuzz
-
-        filename = Path(ttFont.reader.file.name)
-        vharfbuzz = Vharfbuzz(filename)
-    except ImportError:
-        exit_with_install_instructions("shaping")
+    filename = Path(ttFont.reader.file.name)
+    vharfbuzz = Vharfbuzz(filename)
 
     shaping_file_found = False
     ran_a_test = False

Lib/fontbakery/profiles/ufo_sources.py

@@ -7,6 +7,11 @@
 from fontbakery.fonts_profile import profile_factory
 from fontbakery.utils import exit_with_install_instructions
 
+try:
+    import defcon
+except ImportError:
+    exit_with_install_instructions("ufo-sources")
+
 
 profile = profile_factory(default_section=Section("UFO Sources"))
 
@@ -26,13 +31,10 @@
 @condition
 def ufo_font(ufo):
     from fontTools.ufoLib.errors import UFOLibError
+    import defcon
 
     try:
-        import defcon
-
         return defcon.Font(ufo)
-    except ImportError:
-        exit_with_install_instructions("ufo-sources")
     except UFOLibError:
         return None