[Qemu-devel] [PATCH v6 09/12] qapi: Defer 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.

However, the union-clash-type test exposes one weakness in this
patch - it claims the collision is with 'type', even though the
C struct only has a duplicate 'kind'.  We will eventually fix
the generated C to use 'type' like QMP already does, but in the
short term, the next patch will fix things to find the correct
collision.

No change to generated code.

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

---
v6: new patch
---
 scripts/qapi.py                            | 44 ++++++++++++------------------
 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-clash-type.json    |  2 ++
 tests/qapi-schema/union-max.err            |  2 +-
 13 files changed, 25 insertions(+), 44 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 e58c5a8..d90399a 100644
--- a/scripts/qapi.py
+++ b/scripts/qapi.py
@@ -530,7 +530,6 @@ 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.

@@ -591,34 +590,16 @@ 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,
@@ -637,7 +618,6 @@ 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,
@@ -648,12 +628,6 @@ 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):
@@ -873,7 +847,23 @@ class QAPISchemaEnumType(QAPISchemaType):
         self.prefix = prefix

     def check(self, schema):
-        assert len(set(self.values)) == len(self.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 self.name[-4:] == 'Kind':
+                    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 c_type(self, is_param=False):
         return c_name(self.name)
diff --git a/tests/Makefile b/tests/Makefile
index edf310d..79fb154 100644
--- a/tests/Makefile
+++ b/tests/Makefile
@@ -332,7 +332,6 @@ 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..451d5f2 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:10: 'type' (branch of TestUnion) collides with 'type' (member of TestUnion)
diff --git a/tests/qapi-schema/union-clash-type.json b/tests/qapi-schema/union-clash-type.json
index cfc256b..6101e49 100644
--- a/tests/qapi-schema/union-clash-type.json
+++ b/tests/qapi-schema/union-clash-type.json
@@ -2,6 +2,8 @@
 # Reject this, because we would have a clash in generated C, between the
 # simple union's implicit tag member 'kind' and the branch name 'kind'
 # within the union.
+# FIXME: Right now, the test claims the collision is on 'type'; if the
+# second branch is renamed, the code mistakenly parses successfully.
 # TODO: Even when the generated C is switched to use 'type' rather than
 # 'kind', to match the QMP spelling, the collision should still be detected.
 # Or, we could munge the branch name to allow compilation.
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