[Qemu-devel] [PATCH v5 14/28] qapi: Better error messages for bad expressions

[Eric Blake <eblake@redhat.com>]

The previous commit demonstrated that the generator overlooked some
fairly basic broken expressions:
- missing metataype
- metatype key has a non-string value
- unknown key in relation to the metatype
- conflicting metatype (this patch treats the second metatype as an
unknown key of the first key visited, which is not necessarily the
first key the user typed)

Add check_keys to cover these situations, and update testcases to
match.  A couple other tests (enum-missing-data, indented-expr) had
to change since the validation added here occurs so early.

While valid .json files won't trigger any of these cases, we might
as well be nicer to developers that make a typo while trying to add
new QAPI code.

Signed-off-by: Eric Blake <eblake@redhat.com>
---
 scripts/qapi.py                         | 45 +++++++++++++++++++++++++++------
 tests/qapi-schema/alternate-base.err    |  2 +-
 tests/qapi-schema/bad-type-dict.err     |  1 +
 tests/qapi-schema/bad-type-dict.exit    |  2 +-
 tests/qapi-schema/bad-type-dict.json    |  2 +-
 tests/qapi-schema/bad-type-dict.out     |  3 ---
 tests/qapi-schema/double-type.err       |  1 +
 tests/qapi-schema/double-type.exit      |  2 +-
 tests/qapi-schema/double-type.json      |  2 +-
 tests/qapi-schema/double-type.out       |  3 ---
 tests/qapi-schema/enum-missing-data.err |  2 +-
 tests/qapi-schema/indented-expr.json    |  4 +--
 tests/qapi-schema/indented-expr.out     |  2 +-
 tests/qapi-schema/missing-type.err      |  1 +
 tests/qapi-schema/missing-type.exit     |  2 +-
 tests/qapi-schema/missing-type.json     |  2 +-
 tests/qapi-schema/missing-type.out      |  3 ---
 tests/qapi-schema/unknown-expr-key.err  |  1 +
 tests/qapi-schema/unknown-expr-key.exit |  2 +-
 tests/qapi-schema/unknown-expr-key.json |  2 +-
 tests/qapi-schema/unknown-expr-key.out  |  3 ---
 21 files changed, 54 insertions(+), 33 deletions(-)

diff --git a/scripts/qapi.py b/scripts/qapi.py
index 018ec45..90eb3bc 100644
--- a/scripts/qapi.py
+++ b/scripts/qapi.py
@@ -341,12 +341,6 @@ def check_alternate(expr, expr_info):
     values = { 'MAX': '(automatic)' }
     types_seen = {}

-    base = expr.get('base')
-    if base:
-        raise QAPIExprError(expr_info,
-                            "Alternate '%s' must not have a base"
-                            % name)
-
     # Check every branch
     for (key, value) in members.items():
         # Check for conflicts in the generated enum
@@ -408,6 +402,26 @@ def check_exprs(schema):
         elif expr.has_key('event'):
             check_event(expr, info)

+def check_keys(expr_elem, meta, required, optional=[]):
+    expr = expr_elem['expr']
+    info = expr_elem['info']
+    name = expr[meta]
+    if not isinstance(name, str):
+        raise QAPIExprError(info,
+                            "%s key must have a string value" % meta)
+    required = required + [ meta ]
+    for (key, value) in expr.items():
+        if not key in required and not key in optional:
+            raise QAPIExprError(info,
+                                "%s '%s' has unknown key '%s'"
+                                % (meta, name, key))
+    for key in required:
+        if not expr.has_key(key):
+            raise QAPIExprError(info,
+                                "%s '%s' is missing key '%s'"
+                                % (meta, name, key))
+
+
 def parse_schema(input_file):
     # First pass: read entire file into memory
     try:
@@ -419,15 +433,30 @@ def parse_schema(input_file):
     exprs = []

     try:
-        # Next pass: learn the types.
+        # Next pass: learn the types and check for valid expression keys. At
+        # this point, top-level 'include' has already been flattened.
         for expr_elem in schema.exprs:
             expr = expr_elem['expr']
             if expr.has_key('enum'):
-                add_enum(expr['enum'], expr.get('data'))
+                check_keys(expr_elem, 'enum', ['data'])
+                add_enum(expr['enum'], expr['data'])
             elif expr.has_key('union'):
+                check_keys(expr_elem, 'union', ['data'],
+                           ['base', 'discriminator'])
                 add_union(expr)
+            elif expr.has_key('alternate'):
+                check_keys(expr_elem, 'alternate', ['data'])
             elif expr.has_key('type'):
+                check_keys(expr_elem, 'type', ['data'], ['base'])
                 add_struct(expr)
+            elif expr.has_key('command'):
+                check_keys(expr_elem, 'command', [],
+                           ['data', 'returns', 'gen', 'success-response'])
+            elif expr.has_key('event'):
+                check_keys(expr_elem, 'event', [], ['data'])
+            else:
+                raise QAPIExprError(expr_elem['info'],
+                                    "Expression is missing metatype")
             exprs.append(expr)

         # Try again for hidden UnionKind enum
diff --git a/tests/qapi-schema/alternate-base.err b/tests/qapi-schema/alternate-base.err
index 4a2566e..f9e30e7 100644
--- a/tests/qapi-schema/alternate-base.err
+++ b/tests/qapi-schema/alternate-base.err
@@ -1 +1 @@
-tests/qapi-schema/alternate-base.json:4: Alternate 'Alt' must not have a base
+tests/qapi-schema/alternate-base.json:4: alternate 'Alt' has unknown key 'base'
diff --git a/tests/qapi-schema/bad-type-dict.err b/tests/qapi-schema/bad-type-dict.err
index e69de29..b7c73cc 100644
--- a/tests/qapi-schema/bad-type-dict.err
+++ b/tests/qapi-schema/bad-type-dict.err
@@ -0,0 +1 @@
+tests/qapi-schema/bad-type-dict.json:2: command key must have a string value
diff --git a/tests/qapi-schema/bad-type-dict.exit b/tests/qapi-schema/bad-type-dict.exit
index 573541a..d00491f 100644
--- a/tests/qapi-schema/bad-type-dict.exit
+++ b/tests/qapi-schema/bad-type-dict.exit
@@ -1 +1 @@
-0
+1
diff --git a/tests/qapi-schema/bad-type-dict.json b/tests/qapi-schema/bad-type-dict.json
index 3c392a7..2a91b24 100644
--- a/tests/qapi-schema/bad-type-dict.json
+++ b/tests/qapi-schema/bad-type-dict.json
@@ -1,2 +1,2 @@
-# FIXME: we should reject an expression with a metatype that is not a string
+# we reject an expression with a metatype that is not a string
 { 'command': { } }
diff --git a/tests/qapi-schema/bad-type-dict.out b/tests/qapi-schema/bad-type-dict.out
index c62f1ed..e69de29 100644
--- a/tests/qapi-schema/bad-type-dict.out
+++ b/tests/qapi-schema/bad-type-dict.out
@@ -1,3 +0,0 @@
-[OrderedDict([('command', OrderedDict())])]
-[]
-[]
diff --git a/tests/qapi-schema/double-type.err b/tests/qapi-schema/double-type.err
index e69de29..394127b 100644
--- a/tests/qapi-schema/double-type.err
+++ b/tests/qapi-schema/double-type.err
@@ -0,0 +1 @@
+tests/qapi-schema/double-type.json:2: type 'bar' has unknown key 'command'
diff --git a/tests/qapi-schema/double-type.exit b/tests/qapi-schema/double-type.exit
index 573541a..d00491f 100644
--- a/tests/qapi-schema/double-type.exit
+++ b/tests/qapi-schema/double-type.exit
@@ -1 +1 @@
-0
+1
diff --git a/tests/qapi-schema/double-type.json b/tests/qapi-schema/double-type.json
index 6ca96b9..471623a 100644
--- a/tests/qapi-schema/double-type.json
+++ b/tests/qapi-schema/double-type.json
@@ -1,2 +1,2 @@
-# FIXME: we should reject an expression with ambiguous metatype
+# we reject an expression with ambiguous metatype
 { 'command': 'foo', 'type': 'bar', 'data': { } }
diff --git a/tests/qapi-schema/double-type.out b/tests/qapi-schema/double-type.out
index 3e244f5..e69de29 100644
--- a/tests/qapi-schema/double-type.out
+++ b/tests/qapi-schema/double-type.out
@@ -1,3 +0,0 @@
-[OrderedDict([('command', 'foo'), ('type', 'bar'), ('data', OrderedDict())])]
-[]
-[OrderedDict([('command', 'foo'), ('type', 'bar'), ('data', OrderedDict())])]
diff --git a/tests/qapi-schema/enum-missing-data.err b/tests/qapi-schema/enum-missing-data.err
index b8ccae0..62f4a7f 100644
--- a/tests/qapi-schema/enum-missing-data.err
+++ b/tests/qapi-schema/enum-missing-data.err
@@ -1 +1 @@
-tests/qapi-schema/enum-missing-data.json:2: Enum 'MyEnum' requires an array for 'data'
+tests/qapi-schema/enum-missing-data.json:2: enum 'MyEnum' is missing key 'data'
diff --git a/tests/qapi-schema/indented-expr.json b/tests/qapi-schema/indented-expr.json
index d80af60..7115d31 100644
--- a/tests/qapi-schema/indented-expr.json
+++ b/tests/qapi-schema/indented-expr.json
@@ -1,2 +1,2 @@
-{ 'id' : 'eins' }
- { 'id' : 'zwei' }
+{ 'command' : 'eins' }
+ { 'command' : 'zwei' }
diff --git a/tests/qapi-schema/indented-expr.out b/tests/qapi-schema/indented-expr.out
index 98af89a..b5ce915 100644
--- a/tests/qapi-schema/indented-expr.out
+++ b/tests/qapi-schema/indented-expr.out
@@ -1,3 +1,3 @@
-[OrderedDict([('id', 'eins')]), OrderedDict([('id', 'zwei')])]
+[OrderedDict([('command', 'eins')]), OrderedDict([('command', 'zwei')])]
 []
 []
diff --git a/tests/qapi-schema/missing-type.err b/tests/qapi-schema/missing-type.err
index e69de29..b3e7b14 100644
--- a/tests/qapi-schema/missing-type.err
+++ b/tests/qapi-schema/missing-type.err
@@ -0,0 +1 @@
+tests/qapi-schema/missing-type.json:2: Expression is missing metatype
diff --git a/tests/qapi-schema/missing-type.exit b/tests/qapi-schema/missing-type.exit
index 573541a..d00491f 100644
--- a/tests/qapi-schema/missing-type.exit
+++ b/tests/qapi-schema/missing-type.exit
@@ -1 +1 @@
-0
+1
diff --git a/tests/qapi-schema/missing-type.json b/tests/qapi-schema/missing-type.json
index 1696f5c..ff5349d 100644
--- a/tests/qapi-schema/missing-type.json
+++ b/tests/qapi-schema/missing-type.json
@@ -1,2 +1,2 @@
-# FIXME: we should reject an expression with missing metatype
+# we reject an expression with missing metatype
 { 'data': { } }
diff --git a/tests/qapi-schema/missing-type.out b/tests/qapi-schema/missing-type.out
index 67fd4fa..e69de29 100644
--- a/tests/qapi-schema/missing-type.out
+++ b/tests/qapi-schema/missing-type.out
@@ -1,3 +0,0 @@
-[OrderedDict([('data', OrderedDict())])]
-[]
-[]
diff --git a/tests/qapi-schema/unknown-expr-key.err b/tests/qapi-schema/unknown-expr-key.err
index e69de29..3b35508 100644
--- a/tests/qapi-schema/unknown-expr-key.err
+++ b/tests/qapi-schema/unknown-expr-key.err
@@ -0,0 +1 @@
+tests/qapi-schema/unknown-expr-key.json:2: type 'bar' has unknown key 'bogus'
diff --git a/tests/qapi-schema/unknown-expr-key.exit b/tests/qapi-schema/unknown-expr-key.exit
index 573541a..d00491f 100644
--- a/tests/qapi-schema/unknown-expr-key.exit
+++ b/tests/qapi-schema/unknown-expr-key.exit
@@ -1 +1 @@
-0
+1
diff --git a/tests/qapi-schema/unknown-expr-key.json b/tests/qapi-schema/unknown-expr-key.json
index 1e9282d..ba7bdf3 100644
--- a/tests/qapi-schema/unknown-expr-key.json
+++ b/tests/qapi-schema/unknown-expr-key.json
@@ -1,2 +1,2 @@
-# FIXME: we should reject an expression with unknown top-level keys
+# we reject an expression with unknown top-level keys
 { 'type': 'bar', 'data': { 'string': 'str'}, 'bogus': { } }
diff --git a/tests/qapi-schema/unknown-expr-key.out b/tests/qapi-schema/unknown-expr-key.out
index c93f020..e69de29 100644
--- a/tests/qapi-schema/unknown-expr-key.out
+++ b/tests/qapi-schema/unknown-expr-key.out
@@ -1,3 +0,0 @@
-[OrderedDict([('type', 'bar'), ('data', OrderedDict([('string', 'str')])), ('bogus', OrderedDict())])]
-[]
-[OrderedDict([('type', 'bar'), ('data', OrderedDict([('string', 'str')])), ('bogus', OrderedDict())])]
-- 
2.1.0