[Qemu-devel] [PATCH RFC v4 13/29] qapi: Add tests for empty unions

[Eric Blake <eblake@redhat.com>]

The documentation claims that alternates are useful for
allowing two types, although nothing enforces this.  Meanwhile,
it is silent on whether empty unions are allowed.  In practice,
the generated code will compile, in part because we have a
'void *data' branch; but for an empty alternate it always
fails (at least as of my recent fix to use qtypes directly), and
an empty union (whether simple or flat) always causes an abort().
Add some tests to expose the problems, and adjust existing tests
that should be failing for other reasons.

Not tested here: we have a namespace collision, where if the qapi
schema lists 'data' as one of the possible branch names of a
union, then the generated C code fails to compile due to a
duplicate member 'data'.

Signed-off-by: Eric Blake <eblake@redhat.com>
---
 tests/Makefile                           | 1 +
 tests/qapi-schema/alternate-empty.err    | 0
 tests/qapi-schema/alternate-empty.exit   | 1 +
 tests/qapi-schema/alternate-empty.json   | 2 ++
 tests/qapi-schema/alternate-empty.out    | 3 +++
 tests/qapi-schema/alternate-nested.json  | 2 +-
 tests/qapi-schema/alternate-unknown.json | 2 +-
 tests/qapi-schema/flat-union-empty.err   | 0
 tests/qapi-schema/flat-union-empty.exit  | 1 +
 tests/qapi-schema/flat-union-empty.json  | 4 ++++
 tests/qapi-schema/flat-union-empty.out   | 7 +++++++
 tests/qapi-schema/union-empty.err        | 0
 tests/qapi-schema/union-empty.exit       | 1 +
 tests/qapi-schema/union-empty.json       | 2 ++
 tests/qapi-schema/union-empty.out        | 4 ++++
 15 files changed, 28 insertions(+), 2 deletions(-)
 create mode 100644 tests/qapi-schema/alternate-empty.err
 create mode 100644 tests/qapi-schema/alternate-empty.exit
 create mode 100644 tests/qapi-schema/alternate-empty.json
 create mode 100644 tests/qapi-schema/alternate-empty.out
 create mode 100644 tests/qapi-schema/flat-union-empty.err
 create mode 100644 tests/qapi-schema/flat-union-empty.exit
 create mode 100644 tests/qapi-schema/flat-union-empty.json
 create mode 100644 tests/qapi-schema/flat-union-empty.out
 create mode 100644 tests/qapi-schema/union-empty.err
 create mode 100644 tests/qapi-schema/union-empty.exit
 create mode 100644 tests/qapi-schema/union-empty.json
 create mode 100644 tests/qapi-schema/union-empty.out

diff --git a/tests/Makefile b/tests/Makefile
index 1d06fa8..d1d647f 100644
--- a/tests/Makefile
+++ b/tests/Makefile
@@ -246,6 +246,7 @@ check-qapi-schema-y := $(addprefix tests/qapi-schema/, \
 	unclosed-list.json unclosed-object.json unclosed-string.json \
 	duplicate-key.json union-invalid-base.json union-bad-branch.json \
 	union-optional-branch.json union-unknown.json union-max.json \
+	union-empty.json flat-union-empty.json alternate-empty.json \
 	flat-union-optional-discriminator.json flat-union-no-base.json \
 	flat-union-invalid-discriminator.json flat-union-inline.json \
 	flat-union-invalid-branch-key.json flat-union-reverse-define.json \
diff --git a/tests/qapi-schema/alternate-empty.err b/tests/qapi-schema/alternate-empty.err
new file mode 100644
index 0000000..e69de29
diff --git a/tests/qapi-schema/alternate-empty.exit b/tests/qapi-schema/alternate-empty.exit
new file mode 100644
index 0000000..573541a
--- /dev/null
+++ b/tests/qapi-schema/alternate-empty.exit
@@ -0,0 +1 @@
+0
diff --git a/tests/qapi-schema/alternate-empty.json b/tests/qapi-schema/alternate-empty.json
new file mode 100644
index 0000000..db3820f
--- /dev/null
+++ b/tests/qapi-schema/alternate-empty.json
@@ -0,0 +1,2 @@
+# FIXME - alternates should list at least two types to be useful
+{ 'alternate': 'Alt', 'data': { 'i': 'int' } }
diff --git a/tests/qapi-schema/alternate-empty.out b/tests/qapi-schema/alternate-empty.out
new file mode 100644
index 0000000..9b010d8
--- /dev/null
+++ b/tests/qapi-schema/alternate-empty.out
@@ -0,0 +1,3 @@
+object :empty
+alternate Alt
+    case i: int
diff --git a/tests/qapi-schema/alternate-nested.json b/tests/qapi-schema/alternate-nested.json
index c4233b9..8e22186 100644
--- a/tests/qapi-schema/alternate-nested.json
+++ b/tests/qapi-schema/alternate-nested.json
@@ -2,4 +2,4 @@
 { 'alternate': 'Alt1',
   'data': { 'name': 'str', 'value': 'int' } }
 { 'alternate': 'Alt2',
-  'data': { 'nested': 'Alt1' } }
+  'data': { 'nested': 'Alt1', 'b': 'bool' } }
diff --git a/tests/qapi-schema/alternate-unknown.json b/tests/qapi-schema/alternate-unknown.json
index ad5c103..08c80dc 100644
--- a/tests/qapi-schema/alternate-unknown.json
+++ b/tests/qapi-schema/alternate-unknown.json
@@ -1,3 +1,3 @@
 # we reject an alternate with unknown type in branch
 { 'alternate': 'Alt',
-  'data': { 'unknown': 'MissingType' } }
+  'data': { 'unknown': 'MissingType', 'i': 'int' } }
diff --git a/tests/qapi-schema/flat-union-empty.err b/tests/qapi-schema/flat-union-empty.err
new file mode 100644
index 0000000..e69de29
diff --git a/tests/qapi-schema/flat-union-empty.exit b/tests/qapi-schema/flat-union-empty.exit
new file mode 100644
index 0000000..573541a
--- /dev/null
+++ b/tests/qapi-schema/flat-union-empty.exit
@@ -0,0 +1 @@
+0
diff --git a/tests/qapi-schema/flat-union-empty.json b/tests/qapi-schema/flat-union-empty.json
new file mode 100644
index 0000000..67dd297
--- /dev/null
+++ b/tests/qapi-schema/flat-union-empty.json
@@ -0,0 +1,4 @@
+# FIXME - flat unions should not be empty
+{ 'enum': 'Empty', 'data': [ ] }
+{ 'struct': 'Base', 'data': { 'type': 'Empty' } }
+{ 'union': 'Union', 'base': 'Base', 'discriminator': 'type', 'data': { } }
diff --git a/tests/qapi-schema/flat-union-empty.out b/tests/qapi-schema/flat-union-empty.out
new file mode 100644
index 0000000..0e0665a
--- /dev/null
+++ b/tests/qapi-schema/flat-union-empty.out
@@ -0,0 +1,7 @@
+object :empty
+object Base
+    member type: Empty optional=False
+enum Empty []
+object Union
+    base Base
+    tag type
diff --git a/tests/qapi-schema/union-empty.err b/tests/qapi-schema/union-empty.err
new file mode 100644
index 0000000..e69de29
diff --git a/tests/qapi-schema/union-empty.exit b/tests/qapi-schema/union-empty.exit
new file mode 100644
index 0000000..573541a
--- /dev/null
+++ b/tests/qapi-schema/union-empty.exit
@@ -0,0 +1 @@
+0
diff --git a/tests/qapi-schema/union-empty.json b/tests/qapi-schema/union-empty.json
new file mode 100644
index 0000000..1785007
--- /dev/null
+++ b/tests/qapi-schema/union-empty.json
@@ -0,0 +1,2 @@
+# FIXME - unions should not be empty
+{ 'union': 'Union', 'data': { } }
diff --git a/tests/qapi-schema/union-empty.out b/tests/qapi-schema/union-empty.out
new file mode 100644
index 0000000..c5500da
--- /dev/null
+++ b/tests/qapi-schema/union-empty.out
@@ -0,0 +1,4 @@
+object :empty
+object Union
+    tag type
+enum UnionKind []
-- 
2.4.3