[Qemu-devel] [PATCH v8 16/18] qapi: Move duplicate enum value checks to schema check()

[Eric Blake <eblake@redhat.com>]

Similar to the previous commit, move the detection of a collision
in enum values from parse time to QAPISchemaEnumType.check().
This happens to also detect collisions in union branch names,
so for a decent error message, we have to determine if the enum
is implicit (and if so where the real collision lies).

Testing this showed that the test union-bad-branch and
union-clash-branches were basically testing the same thing;
with the minor difference that the former clashes only in the
enum, while the latter also clashes in the C union member
names that would be generated. So delete the weaker test.

No change to generated code.

Signed-off-by: Eric Blake <eblake@redhat.com>

---
v8: rebase to earlier changes; better comments
v7: retitle and improve commit message; earlier subclass patches
avoid problem with detecting 'kind' collision
v6: new patch
---
 scripts/qapi.py                            | 54 +++++++++++++-----------------
 tests/Makefile                             |  1 -
 tests/qapi-schema/alternate-clash.err      |  2 +-
 tests/qapi-schema/enum-clash-member.err    |  2 +-
 tests/qapi-schema/enum-max-member.err      |  2 +-
 tests/qapi-schema/union-bad-branch.err     |  1 -
 tests/qapi-schema/union-bad-branch.exit    |  1 -
 tests/qapi-schema/union-bad-branch.json    |  8 -----
 tests/qapi-schema/union-bad-branch.out     |  0
 tests/qapi-schema/union-clash-branches.err |  2 +-
 tests/qapi-schema/union-clash-type.err     |  2 +-
 tests/qapi-schema/union-max.err            |  2 +-
 12 files changed, 29 insertions(+), 48 deletions(-)
 delete mode 100644 tests/qapi-schema/union-bad-branch.err
 delete mode 100644 tests/qapi-schema/union-bad-branch.exit
 delete mode 100644 tests/qapi-schema/union-bad-branch.json
 delete mode 100644 tests/qapi-schema/union-bad-branch.out

diff --git a/scripts/qapi.py b/scripts/qapi.py
index 144dd4a..b21e38e 100644
--- a/scripts/qapi.py
+++ b/scripts/qapi.py
@@ -527,7 +527,6 @@ def check_union(expr, expr_info):
     base = expr.get('base')
     discriminator = expr.get('discriminator')
     members = expr['data']
-    values = {'MAX': '(automatic)', 'KIND': '(automatic)'}

     # Two types of unions, determined by discriminator.

@@ -587,34 +586,16 @@ def check_union(expr, expr_info):
                                     "enum '%s'" %
                                     (key, enum_define["enum_name"]))

-        # Otherwise, check for conflicts in the generated enum
-        else:
-            c_key = camel_to_upper(key)
-            if c_key in values:
-                raise QAPIExprError(expr_info,
-                                    "Union '%s' member '%s' clashes with '%s'"
-                                    % (name, key, values[c_key]))
-            values[c_key] = key
-

 def check_alternate(expr, expr_info):
     name = expr['alternate']
     members = expr['data']
-    values = {'MAX': '(automatic)'}
     types_seen = {}

     # Check every branch
     for (key, value) in members.items():
         check_name(expr_info, "Member of alternate '%s'" % name, key)

-        # Check for conflicts in the generated enum
-        c_key = camel_to_upper(key)
-        if c_key in values:
-            raise QAPIExprError(expr_info,
-                                "Alternate '%s' member '%s' clashes with '%s'"
-                                % (name, key, values[c_key]))
-        values[c_key] = key
-
         # Ensure alternates have no type conflicts.
         check_type(expr_info, "Member '%s' of alternate '%s'" % (key, name),
                    value,
@@ -633,7 +614,6 @@ def check_enum(expr, expr_info):
     name = expr['enum']
     members = expr.get('data')
     prefix = expr.get('prefix')
-    values = {'MAX': '(automatic)'}

     if not isinstance(members, list):
         raise QAPIExprError(expr_info,
@@ -644,12 +624,6 @@ def check_enum(expr, expr_info):
     for member in members:
         check_name(expr_info, "Member of enum '%s'" % name, member,
                    enum_member=True)
-        key = camel_to_upper(member)
-        if key in values:
-            raise QAPIExprError(expr_info,
-                                "Enum '%s' member '%s' clashes with '%s'"
-                                % (name, member, values[key]))
-        values[key] = member


 def check_struct(expr, expr_info):
@@ -878,7 +852,26 @@ class QAPISchemaEnumType(QAPISchemaType):
         self.prefix = prefix

     def check(self, schema):
-        assert len(set(self.values)) == len(self.values)
+        # Check for collisions on the generated C enum values
+        seen = {c_enum_const(self.name, 'MAX'): '(automatic MAX)'}
+        for value in self.values:
+            c_value = c_enum_const(self.name, value)
+            if c_value in seen:
+                # If the enum is implicit, report the error on behalf of
+                # the union or alternate that triggered the enum
+                if self.is_implicit():
+                    owner = schema.lookup_type(self.name[:-4])
+                    assert owner
+                    if isinstance(owner, QAPISchemaAlternateType):
+                        description = "Alternate '%s' branch" % owner.name
+                    else:
+                        description = "Union '%s' branch" % owner.name
+                else:
+                    description = "Enum '%s' value" % self.name
+                raise QAPIExprError(self.info,
+                                    "%s '%s' clashes with '%s'"
+                                    % (description, value, seen[c_value]))
+            seen[c_value] = value

     def is_implicit(self):
         # See QAPISchema._make_implicit_enum_type()
@@ -1084,10 +1077,9 @@ class QAPISchemaObjectTypeVariant(QAPISchemaObjectTypeMember):
     # solely by their different tag_type
     def check(self, schema, info, tag_type, seen, union):
         # Check that the branch name does not collide with non-variant C
-        # members, without modifying caller's copy of seen
-        # TODO Detect collisions between branch names in C - easiest
-        # will be to check instead for collisions in the corresponding
-        # enum type
+        # members, without modifying caller's copy of seen.  Collisions
+        # between branch names in C is detected elsewhere, when validating
+        # that the correpsonding enum of tag_type has no collision.
         QAPISchemaObjectTypeMember.check(self, schema, info, [], dict(seen))
         assert self.name in tag_type.values

diff --git a/tests/Makefile b/tests/Makefile
index 35a63f3..2cd5d31 100644
--- a/tests/Makefile
+++ b/tests/Makefile
@@ -331,7 +331,6 @@ qapi-schema += unclosed-list.json
 qapi-schema += unclosed-object.json
 qapi-schema += unclosed-string.json
 qapi-schema += unicode-str.json
-qapi-schema += union-bad-branch.json
 qapi-schema += union-base-no-discriminator.json
 qapi-schema += union-clash-branches.json
 qapi-schema += union-clash-data.json
diff --git a/tests/qapi-schema/alternate-clash.err b/tests/qapi-schema/alternate-clash.err
index a475ab6..7fd3069 100644
--- a/tests/qapi-schema/alternate-clash.err
+++ b/tests/qapi-schema/alternate-clash.err
@@ -1 +1 @@
-tests/qapi-schema/alternate-clash.json:7: Alternate 'Alt1' member 'a_b' clashes with 'a-b'
+tests/qapi-schema/alternate-clash.json:7: Alternate 'Alt1' branch 'a_b' clashes with 'a-b'
diff --git a/tests/qapi-schema/enum-clash-member.err b/tests/qapi-schema/enum-clash-member.err
index 48bd136..84030c5 100644
--- a/tests/qapi-schema/enum-clash-member.err
+++ b/tests/qapi-schema/enum-clash-member.err
@@ -1 +1 @@
-tests/qapi-schema/enum-clash-member.json:2: Enum 'MyEnum' member 'ONE' clashes with 'one'
+tests/qapi-schema/enum-clash-member.json:2: Enum 'MyEnum' value 'ONE' clashes with 'one'
diff --git a/tests/qapi-schema/enum-max-member.err b/tests/qapi-schema/enum-max-member.err
index f77837f..6b9ef9b 100644
--- a/tests/qapi-schema/enum-max-member.err
+++ b/tests/qapi-schema/enum-max-member.err
@@ -1 +1 @@
-tests/qapi-schema/enum-max-member.json:3: Enum 'MyEnum' member 'max' clashes with '(automatic)'
+tests/qapi-schema/enum-max-member.json:3: Enum 'MyEnum' value 'max' clashes with '(automatic MAX)'
diff --git a/tests/qapi-schema/union-bad-branch.err b/tests/qapi-schema/union-bad-branch.err
deleted file mode 100644
index 8822735..0000000
--- a/tests/qapi-schema/union-bad-branch.err
+++ /dev/null
@@ -1 +0,0 @@
-tests/qapi-schema/union-bad-branch.json:6: Union 'MyUnion' member 'ONE' clashes with 'one'
diff --git a/tests/qapi-schema/union-bad-branch.exit b/tests/qapi-schema/union-bad-branch.exit
deleted file mode 100644
index d00491f..0000000
--- a/tests/qapi-schema/union-bad-branch.exit
+++ /dev/null
@@ -1 +0,0 @@
-1
diff --git a/tests/qapi-schema/union-bad-branch.json b/tests/qapi-schema/union-bad-branch.json
deleted file mode 100644
index 913aa38..0000000
--- a/tests/qapi-schema/union-bad-branch.json
+++ /dev/null
@@ -1,8 +0,0 @@
-# we reject normal unions where branches would collide in C
-{ 'struct': 'One',
-  'data': { 'string': 'str' } }
-{ 'struct': 'Two',
-  'data': { 'number': 'int' } }
-{ 'union': 'MyUnion',
-  'data': { 'one': 'One',
-            'ONE': 'Two' } }
diff --git a/tests/qapi-schema/union-bad-branch.out b/tests/qapi-schema/union-bad-branch.out
deleted file mode 100644
index e69de29..0000000
diff --git a/tests/qapi-schema/union-clash-branches.err b/tests/qapi-schema/union-clash-branches.err
index 005c48d..d8f1265 100644
--- a/tests/qapi-schema/union-clash-branches.err
+++ b/tests/qapi-schema/union-clash-branches.err
@@ -1 +1 @@
-tests/qapi-schema/union-clash-branches.json:4: Union 'TestUnion' member 'a_b' clashes with 'a-b'
+tests/qapi-schema/union-clash-branches.json:4: Union 'TestUnion' branch 'a_b' clashes with 'a-b'
diff --git a/tests/qapi-schema/union-clash-type.err b/tests/qapi-schema/union-clash-type.err
index a5dead1..ce7f8cd 100644
--- a/tests/qapi-schema/union-clash-type.err
+++ b/tests/qapi-schema/union-clash-type.err
@@ -1 +1 @@
-tests/qapi-schema/union-clash-type.json:8: Union 'TestUnion' member 'kind' clashes with '(automatic)'
+tests/qapi-schema/union-clash-type.json:8: 'kind' (branch of TestUnion) collides with 'kind' (implicit tag of TestUnion)
diff --git a/tests/qapi-schema/union-max.err b/tests/qapi-schema/union-max.err
index 55ce439..b93beae 100644
--- a/tests/qapi-schema/union-max.err
+++ b/tests/qapi-schema/union-max.err
@@ -1 +1 @@
-tests/qapi-schema/union-max.json:2: Union 'Union' member 'max' clashes with '(automatic)'
+tests/qapi-schema/union-max.json:2: Union 'Union' branch 'max' clashes with '(automatic MAX)'
-- 
2.4.3