More improvements

1. Fix failure finding UserError.
2. Fix bad string formatting.
3. Add test case covering passing an invalid hash format.
4. Remove blake2b, as I haven't tested it. We can add it some day if people want it.

6 files changed, 32 insertions, 16 deletions

diff --git a/CHANGES.txt b/CHANGES.txt
index 4803ab3..4dd0fd7 100755
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -40,7 +40,7 @@ RELEASE  VERSION/DATE TO BE FILLED IN LATER
       when running multiple tests with multiple jobs.
     - Added support for a new command-line parameter `--hash-format` to override the default
       hash format that SCons uses. It can also be set via `SetOption('hash_format')`. Supported
-      values include `md5`, `sha1`, `sha256`, and `blake2b`. For all hash formats other than
+      values are: `md5`, `sha1`, and `sha256`. For all hash formats other than
       the default of `md5`, the SConsign database will include the name of the hash format.
       In addition, the default Decider is now called `content` instead of `MD5`.
     - Fix incorrect cache hits and/or misses when running in interactive mode by having
diff --git a/SCons/Script/SConsOptions.py b/SCons/Script/SConsOptions.py
index ae1cac5..c72f670 100644
--- a/SCons/Script/SConsOptions.py
+++ b/SCons/Script/SConsOptions.py
@@ -729,7 +729,7 @@ def Parser(version):
     op.add_option('--hash-format',
                   dest='hash_format',
                   action='store',
-                  help='Hash format (e.g. md5, sha1, sha256, or blake2b).')
+                  help='Hash format (e.g. md5, sha1, or sha256).')
 
     op.add_option('-i', '--ignore-errors',
                   dest='ignore_errors', default=False,
diff --git a/SCons/Util.py b/SCons/Util.py
index d341709..d2a7e48 100644
--- a/SCons/Util.py
+++ b/SCons/Util.py
@@ -1500,16 +1500,17 @@ def set_hash_format(hash_format):
     _hash_format = hash_format
     if hash_format:
         hash_format_lower = hash_format.lower()
-        allowed_hash_formats = ['md5', 'sha1', 'sha256', 'blake2b']
+        allowed_hash_formats = ['md5', 'sha1', 'sha256']
         if hash_format_lower not in allowed_hash_formats:
-            from SCons.Warnings import UserError
+            from SCons.Errors import UserError
             raise UserError('Hash format "%s" is not supported by SCons. Only '
-                            'the following hash formats are supported.' %
-                            allowed_hash_formats)
+                            'the following hash formats are supported: %s' %
+                            (hash_format_lower,
+                             ', '.join(allowed_hash_formats)))
 
         _hash_function = getattr(hashlib, hash_format_lower, None)
         if _hash_function is None:
-            from SCons.Warnings import UserError
+            from SCons.Errors import UserError
             raise UserError(
                 'Hash format "%s" is not available in your Python '
                 'interpreter.' % hash_format_lower)
@@ -1526,7 +1527,7 @@ def set_hash_format(hash_format):
                 pass
         else:
             # This is not expected to happen in practice.
-            from SCons.Warnings import UserError
+            from SCons.Errors import UserError
             raise UserError(
                 'Your Python interpreter does not have MD5, SHA1, or SHA256. '
                 'SCons requires at least one.')
diff --git a/doc/man/scons.xml b/doc/man/scons.xml
index f077735..f4333a0 100644
--- a/doc/man/scons.xml
+++ b/doc/man/scons.xml
@@ -1125,7 +1125,7 @@ the help message not to be displayed.
 This value determines the hashing algorithm used in generating content signatures
 or &f-link-CacheDir; keys.</para>
 
-<para>The supported list of values are: md5, sha1, sha256, and blake2b.
+<para>The supported list of values are: md5, sha1, and sha256.
 However, the Python interpreter used to run SCons must have the corresponding
 support available in hashlib to use the specified algorithm.</para>
   </listitem>
diff --git a/test/option/hash-format.py b/test/option/hash-format.py
index 43e5ad7..9fa10ee 100644
--- a/test/option/hash-format.py
+++ b/test/option/hash-format.py
@@ -29,19 +29,26 @@ import os
 import TestSCons
 
 # Test passing the hash format by command-line.
-for algorithm in ['md5', 'sha1', 'sha256', 'blake2b', None]:
+INVALID_ALGORITHM = 'testfailure'
+for algorithm in ['md5', 'sha1', 'sha256', INVALID_ALGORITHM, None]:
     test = TestSCons.TestSCons()
     test.dir_fixture('hash-format')
 
-    if algorithm is not None:
+    if algorithm == INVALID_ALGORITHM:
+        # Expect failure due to an unsupported/invalid algorithm.
+        test.run('--hash-format=%s .' % algorithm, stderr=r"""
+scons: \*\*\* Hash format "{}" is not supported by SCons. Only the following hash formats are supported: md5, sha1, sha256
+File "[^"]+", line \d+, in \S+
+""".format(algorithm), status=2, match=TestSCons.match_re)
+        continue
+    elif algorithm is not None:
         # Skip any algorithm that the Python interpreter doesn't have.
         if hasattr(hashlib, algorithm):
             expected_dblite = test.workpath('.sconsign_%s.dblite' % algorithm)
             test.run('--hash-format=%s .' % algorithm)
         else:
-            test.skip_test('Skipping test with --hash-format=%s because that '
-                           'algorithm is not available.' % algorithm)
-            continue
+            print('Skipping test with --hash-format=%s because that '
+                  'algorithm is not available.' % algorithm)
     else:
         # The SConsign file in the hash-format folder has logic to call
         # SCons.Util.set_hash_format('sha256') if the default algorithm is
@@ -56,7 +63,15 @@ for algorithm in ['md5', 'sha1', 'sha256', 'blake2b', None]:
     assert os.path.isfile(expected_dblite), \
         "%s does not exist when running algorithm %s" % (expected_dblite,
                                                          algorithm)
-    test.pass_test()
+
+    test.run('-C .')
+    os.unlink(expected_dblite)
+
+# In this case, the SConstruct file will use SetOption to override the hash
+# format.
+test.run()
+
+test.pass_test()
 
 # Local Variables:
 # tab-width:4
diff --git a/test/option/hash-format/SConstruct b/test/option/hash-format/SConstruct
index 8d600d7..de76e1b 100644
--- a/test/option/hash-format/SConstruct
+++ b/test/option/hash-format/SConstruct
@@ -21,7 +21,7 @@ def VerifyCsig():
         assert csig == 'efe5c6daa743540e9561934e3e18628b336013f7', csig
     elif hash_format == 'sha256':
         assert csig == 'a28bb79aa5ca8a5eb2dc5910a103d1a6312e79d73ed8054787cee78cc532a6aa', csig
-    else:
+    elif hash_format != 'testfailure':
         raise Exception('Hash format %s is not supported in '
                         'test/option/hash-format/SConstruct' % hash_format)
 atexit.register(VerifyCsig)