qapi: Require member documentation (with loophole)

The QAPI generator forces you to document your stuff.  Except for
command arguments, event data, and members of enum and object types:
these the generator silently "documents" as "Not documented".

We can't require proper documentation there without first fixing all
the offenders.  We've always had too many offenders to pull that off.
Right now, we have more than 500.  Worse, we seem to fix old ones no
faster than we add new ones: in the past year, we fixed 22 ones, but
added 26 new ones.

To help arrest the backsliding, make missing documentation an error
unless the command, type, or event is in listed in new pragma
documentation-exceptions.

List all the current offenders: 117 commands and types in qapi/, and 9
in qga/.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-ID: <20240205074709.3613229-7-armbru@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>

7 files changed, 149 insertions, 3 deletions

diff --git a/docs/devel/qapi-code-gen.rst b/docs/devel/qapi-code-gen.rst
index 69c8a1e..756adc1 100644
--- a/docs/devel/qapi-code-gen.rst
+++ b/docs/devel/qapi-code-gen.rst
@@ -167,6 +167,7 @@ Syntax::
                    '*doc-required': BOOL,
                    '*command-name-exceptions': [ STRING, ... ],
                    '*command-returns-exceptions': [ STRING, ... ],
+                   '*documentation-exceptions': [ STRING, ... ],
                    '*member-name-exceptions': [ STRING, ... ] } }
 
 The pragma directive lets you control optional generator behavior.
@@ -183,6 +184,10 @@ may contain ``"_"`` instead of ``"-"``.  Default is none.
 Pragma 'command-returns-exceptions' takes a list of commands that may
 violate the rules on permitted return types.  Default is none.
 
+Pragma 'documentation-exceptions' takes a list of types, commands, and
+events whose members / arguments need not be documented.  Default is
+none.
+
 Pragma 'member-name-exceptions' takes a list of types whose member
 names may contain uppercase letters, and ``"_"`` instead of ``"-"``.
 Default is none.
diff --git a/qapi/pragma.json b/qapi/pragma.json
index 0aa4eed..0fa6474 100644
--- a/qapi/pragma.json
+++ b/qapi/pragma.json
@@ -31,6 +31,125 @@
         'query-tpm-models',
         'query-tpm-types',
         'ringbuf-read' ],
+    # Types, commands, and events with undocumented members / arguments:
+    'documentation-exceptions': [
+        'AbortWrapper',
+        'AudiodevDriver',
+        'BlkdebugEvent',
+        'BlockDirtyBitmapAddWrapper',
+        'BlockDirtyBitmapMergeWrapper',
+        'BlockDirtyBitmapWrapper',
+        'BlockExportOptions',
+        'BlockStatsSpecific',
+        'BlockdevBackupWrapper',
+        'BlockdevDriver',
+        'BlockdevQcow2Encryption',
+        'BlockdevQcow2EncryptionFormat',
+        'BlockdevQcowEncryption',
+        'BlockdevSnapshotInternalWrapper',
+        'BlockdevSnapshotSyncWrapper',
+        'BlockdevSnapshotWrapper',
+        'BlockdevVmdkAdapterType',
+        'ChardevBackend',
+        'ChardevBackendKind',
+        'ChardevCommonWrapper',
+        'ChardevDBusWrapper',
+        'ChardevFileWrapper',
+        'ChardevHostdevWrapper',
+        'ChardevMuxWrapper',
+        'ChardevQemuVDAgentWrapper',
+        'ChardevRingbufWrapper',
+        'ChardevSocketWrapper',
+        'ChardevSpiceChannelWrapper',
+        'ChardevSpicePortWrapper',
+        'ChardevStdioWrapper',
+        'ChardevUdpWrapper',
+        'ChardevVCWrapper',
+        'CpuS390Entitlement',
+        'CpuS390Polarization',
+        'CpuS390State',
+        'CxlCorErrorType',
+        'DisplayProtocol',
+        'DriveBackupWrapper',
+        'DummyBlockCoreForceArrays',
+        'DummyForceArrays',
+        'DummyVirtioForceArrays',
+        'DumpGuestMemoryCapability',
+        'GrabToggleKeys',
+        'GuestPanicInformationHyperV',
+        'HotKeyMod',
+        'HvBalloonDeviceInfoWrapper',
+        'ImageInfoSpecific',
+        'ImageInfoSpecificFileWrapper',
+        'ImageInfoSpecificKind',
+        'ImageInfoSpecificLUKSWrapper',
+        'ImageInfoSpecificQCow2Wrapper',
+        'ImageInfoSpecificRbdWrapper',
+        'ImageInfoSpecificVmdkWrapper',
+        'InetSocketAddressWrapper',
+        'InputAxis',
+        'InputBtnEventWrapper',
+        'InputButton',
+        'InputKeyEventWrapper',
+        'InputMoveEventWrapper',
+        'InputMultiTouchEvent',
+        'InputMultiTouchEventWrapper',
+        'InputMultiTouchType',
+        'IntWrapper',
+        'IscsiHeaderDigest',
+        'IscsiTransport',
+        'JSONType',
+        'KeyValue',
+        'KeyValueKind',
+        'MemoryDeviceInfo',
+        'MemoryDeviceInfoKind',
+        'MigrateSetParameters',
+        'MigrationAddress',
+        'NetClientDriver',
+        'NumaOptions',
+        'ObjectType',
+        'PCDIMMDeviceInfoWrapper',
+        'PciMemoryRegion',
+        'QCryptoAkCipherKeyType',
+        'QCryptoAkCipherOptions',
+        'QCryptodevBackendServiceType',
+        'QKeyCode',
+        'QKeyCodeWrapper',
+        'Qcow2OverlapCheckFlags',
+        'RbdAuthMode',
+        'RbdEncryptionCreateOptions',
+        'RbdImageEncryptionFormat',
+        'SgxEPCDeviceInfoWrapper',
+        'SocketAddressLegacy',
+        'SshHostKeyCheck',
+        'StatsFilter',
+        'StatsValue',
+        'String',
+        'StringWrapper',
+        'SysEmuTarget',
+        'TPMEmulatorOptionsWrapper',
+        'TPMPassthroughOptionsWrapper',
+        'ThrottleGroupProperties',
+        'TransactionAction',
+        'UnixSocketAddressWrapper',
+        'VirtioMEMDeviceInfoWrapper',
+        'VirtioPMEMDeviceInfoWrapper',
+        'VncPrimaryAuth',
+        'VncVencryptSubAuth',
+        'VsockSocketAddressWrapper',
+        'X86CPURegister32',
+        'XDbgBlockGraph',
+        'YankInstance',
+        'YankInstanceType',
+        'blockdev-reopen',
+        'query-cpu-model-baseline',
+        'query-cpu-model-comparison',
+        'query-cpu-model-expansion',
+        'query-rocker',
+        'query-rocker-ports',
+        'query-stats-schemas',
+        'watchdog-set-action',
+        'yank' ],
     # Externally visible types whose member names may use uppercase
     'member-name-exceptions': [     # visible in:
         'ACPISlotType',             # query-acpi-ospm-status
diff --git a/qga/qapi-schema.json b/qga/qapi-schema.json
index 50b0a55..b9501c8 100644
--- a/qga/qapi-schema.json
+++ b/qga/qapi-schema.json
@@ -33,7 +33,18 @@
         'guest-get-time',
         'guest-set-vcpus',
         'guest-sync',
-        'guest-sync-delimited' ] } }
+        'guest-sync-delimited' ],
+    # Types and commands with undocumented members:
+    'documentation-exceptions': [
+        'GuestCpuStats',
+        'GuestCpuStatsType',
+        'GuestDeviceId',
+        'GuestDeviceType',
+        'GuestDiskSmart',
+        'GuestDiskStatsInfo',
+        'GuestNVMeSmart',
+        'guest-set-memory-blocks',
+        'guest-set-vcpus' ] } }
 
 ##
 # @guest-sync-delimited:
diff --git a/scripts/qapi/parser.py b/scripts/qapi/parser.py
index 48cd55a..88221b3 100644
--- a/scripts/qapi/parser.py
+++ b/scripts/qapi/parser.py
@@ -238,6 +238,8 @@ class QAPISchemaParser:
             pragma.command_name_exceptions = check_list_str(name, value)
         elif name == 'command-returns-exceptions':
             pragma.command_returns_exceptions = check_list_str(name, value)
+        elif name == 'documentation-exceptions':
+            pragma.documentation_exceptions = check_list_str(name, value)
         elif name == 'member-name-exceptions':
             pragma.member_name_exceptions = check_list_str(name, value)
         else:
@@ -739,7 +741,10 @@ class QAPIDoc:
 
     def connect_member(self, member: 'QAPISchemaMember') -> None:
         if member.name not in self.args:
-            # Undocumented TODO outlaw
+            if self.symbol not in member.info.pragma.documentation_exceptions:
+                raise QAPISemError(member.info,
+                                   "%s '%s' lacks documentation"
+                                   % (member.role, member.name))
             self.args[member.name] = QAPIDoc.ArgSection(self._parser,
                                                         member.name)
         self.args[member.name].connect(member)
diff --git a/scripts/qapi/source.py b/scripts/qapi/source.py
index 04193cc..7b379fd 100644
--- a/scripts/qapi/source.py
+++ b/scripts/qapi/source.py
@@ -24,6 +24,8 @@ class QAPISchemaPragma:
         self.command_name_exceptions: List[str] = []
         # Commands allowed to return a non-dictionary
         self.command_returns_exceptions: List[str] = []
+        # Types, commands, and events with undocumented members
+        self.documentation_exceptions: List[str] = []
         # Types whose member names may violate case conventions
         self.member_name_exceptions: List[str] = []
 
diff --git a/tests/qapi-schema/doc-bad-alternate-member.json b/tests/qapi-schema/doc-bad-alternate-member.json
index fa4143d..37593b6 100644
--- a/tests/qapi-schema/doc-bad-alternate-member.json
+++ b/tests/qapi-schema/doc-bad-alternate-member.json
@@ -2,6 +2,8 @@
 
 ##
 # @AorB:
+# @a: a
+# @b: b
 # @aa: a
 # @bb: b
 ##
diff --git a/tests/qapi-schema/doc-good.json b/tests/qapi-schema/doc-good.json
index 976f9e1..24a84fe 100644
--- a/tests/qapi-schema/doc-good.json
+++ b/tests/qapi-schema/doc-good.json
@@ -3,7 +3,9 @@
 #
 # Positive QAPI doc comment tests
 
-{ 'pragma': { 'doc-required': true } }
+{ 'pragma': {
+    'doc-required': true,
+    'documentation-exceptions': [ 'Enum', 'Variant1', 'Alternate', 'cmd' ] } }
 
 ##
 # = Section