Simon Hengel pushed to branch wip/sol/add-rendered-to-json-diagnostics at Glasgow Haskell Compiler / GHC Commits: 8f7994f8 by Simon Hengel at 2025-07-08T05:24:41+07:00 Include the rendered message in -fdiagnostics-as-json output #26173 - - - - - 8 changed files: - compiler/GHC/Driver/Errors.hs - compiler/GHC/Types/Error.hs - compiler/GHC/Utils/Logger.hs - docs/users_guide/9.14.1-notes.rst - + docs/users_guide/diagnostics-as-json-schema-1_2.json - docs/users_guide/using.rst - testsuite/tests/driver/json.stderr - testsuite/tests/driver/json_warn.stderr Changes: ===================================== compiler/GHC/Driver/Errors.hs ===================================== @@ -11,8 +11,9 @@ import GHC.Driver.Errors.Types import GHC.Prelude import GHC.Types.SourceError import GHC.Types.Error +import GHC.Utils.Json import GHC.Utils.Error -import GHC.Utils.Outputable (SDocContext, PprStyle, hang, ppr, ($$), text, mkErrStyle, sdocStyle, updSDocContext) +import GHC.Utils.Outputable import GHC.Utils.Logger printMessages :: forall a. (Diagnostic a) => Logger -> DiagnosticOpts a -> DiagOpts -> Messages a -> IO () @@ -23,9 +24,26 @@ printMessages logger msg_opts opts = mapM_ printMessage . sortMessages printMessage :: MsgEnvelope a -> IO () printMessage message - | log_diags_as_json = logJsonMsg logger messageClass message + | log_diags_as_json = do + docWithHeader <- addCaret logflags messageClass location (addHeader doc) + let + rendered :: String + rendered = renderWithContext (log_default_user_context logflags) docWithHeader + + jsonMessage :: JsonDoc + jsonMessage = case json message of + JSObject xs -> JSObject (("rendered", JSString rendered) : xs) + xs -> xs + logJsonMsg logger messageClass jsonMessage + | otherwise = logMsg logger messageClass location doc where + logflags :: LogFlags + logflags = logFlags logger + + addHeader :: SDoc -> SDoc + addHeader = mkLocMessageWarningGroups (log_show_warn_groups logflags) messageClass location + doc :: SDoc doc = updSDocContext (\_ -> ctx) (messageWithHints diagnostic) ===================================== compiler/GHC/Types/Error.hs ===================================== @@ -573,7 +573,7 @@ instance ToJson DiagnosticCode where {- Note [Diagnostic Message JSON Schema] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The below instance of ToJson must conform to the JSON schema -specified in docs/users_guide/diagnostics-as-json-schema-1_1.json. +specified in docs/users_guide/diagnostics-as-json-schema-1_2.json. When the schema is altered, please bump the version. If the content is altered in a backwards compatible way, update the minor version (e.g. 1.3 ~> 1.4). ===================================== compiler/GHC/Utils/Logger.hs ===================================== @@ -21,6 +21,8 @@ module GHC.Utils.Logger , HasLogger (..) , ContainsLogger (..) + , addCaret + -- * Logger setup , initLogger , LogAction @@ -435,18 +437,51 @@ defaultLogActionWithHandles out err logflags msg_class srcSpan msg message = mkLocMessageWarningGroups (log_show_warn_groups logflags) msg_class srcSpan msg printDiagnostics :: IO () - printDiagnostics = do - caretDiagnostic <- - if log_show_caret logflags - then getCaretDiagnostic msg_class srcSpan - else pure empty - printErrs $ getPprStyle $ \style -> - withPprStyle (setStyleColoured True style) - (message $+$ caretDiagnostic $+$ blankLine) - -- careful (#2302): printErrs prints in UTF-8, - -- whereas converting to string first and using - -- hPutStr would just emit the low 8 bits of - -- each unicode char. + printDiagnostics = addCaret logflags msg_class srcSpan message >>= printErrs + +-- This function is used by `defaultLogActionWithHandles` for non-JSON output, +-- and also by `GHC.Driver.Errors.printMessages` to produce the `rendered` +-- message on `-fdiagnostics-as-json`. +-- +-- We would want to eventually consolidate this. However, this is currently +-- not feasible for the following reasons: +-- +-- 1. Some parts of the compiler sidestep `printMessages`, for that reason we +-- can not decorate (`addCaret` + `defaultLogActionHPrintDoc`) the +-- message in `printMessages`. +-- +-- 2. GHC uses two different code paths for JSON and non-JSON diagnostics. For +-- that reason we can decorate the message in `defaultLogActionWithHandles`. +-- +-- See also Note [JSON Error Messages]: +-- +-- `jsonLogAction` should be removed along with -ddump-json +-- +-- Also note that (1) is the reason why some parts of the compiler produce +-- diagnostics that don't respect `-fdiagnostics-as-json`. +-- +-- The plan as I see it is as follows: +-- +-- 1. Refactor all places in the compiler that report diagnostics to go +-- through `GHC.Driver.Errors.printMessages`. +-- +-- (It's easy to find all those places by looking for who creates +-- MCDiagnostic, either directly or via `mkMCDiagnostic` or +-- `errorDiagnostic`.) +-- +-- 2. Get rid of `-ddump-json`, `jsonLogAction` and consolidate message +-- decoration at one place (either `printMessages` or +-- `defaultLogActionWithHandles`) +-- +addCaret :: LogFlags -> MessageClass -> SrcSpan -> SDoc -> IO SDoc +addCaret logflags msg_class srcSpan message = do + caretDiagnostic <- + if log_show_caret logflags + then getCaretDiagnostic msg_class srcSpan + else pure empty + return $ getPprStyle $ \style -> + withPprStyle (setStyleColoured True style) + (message $+$ caretDiagnostic $+$ blankLine) -- | Like 'defaultLogActionHPutStrDoc' but appends an extra newline. defaultLogActionHPrintDoc :: LogFlags -> Bool -> Handle -> SDoc -> IO () @@ -482,6 +517,8 @@ defaultLogActionHPutStrDoc logflags asciiSpace h d -- -ddump-json is being deprecated, `jsonLogAction` has been added in, but -- it should be removed along with -ddump-json. Similarly, the guard in -- `defaultLogAction` should be removed. This cleanup is tracked in #24113. +-- +-- -- | Default action for 'dumpAction' hook defaultDumpAction :: DumpCache -> LogAction -> DumpAction @@ -611,8 +648,8 @@ defaultTraceAction logflags title doc x = logMsg :: Logger -> MessageClass -> SrcSpan -> SDoc -> IO () logMsg logger mc loc msg = putLogMsg logger (logFlags logger) mc loc msg -logJsonMsg :: ToJson a => Logger -> MessageClass -> a -> IO () -logJsonMsg logger mc d = putJsonLogMsg logger (logFlags logger) mc (json d) +logJsonMsg :: Logger -> MessageClass -> JsonDoc -> IO () +logJsonMsg logger mc = putJsonLogMsg logger (logFlags logger) mc -- | Dump something logDumpFile :: Logger -> PprStyle -> DumpFlag -> String -> DumpFormat -> SDoc -> IO () ===================================== docs/users_guide/9.14.1-notes.rst ===================================== @@ -143,6 +143,11 @@ Compiler were accessed using the generated record selector functions, marking the fields as covered in coverage reports (:ghc-ticket:`17834`). +- JSON diagnostics produced with (:ghc-flag:`-fdiagnostics-as-json`) now + include the `rendered` diagnostics message, in the exact same format as what + GHC would have produced without -fdiagnostics-as-json (including ANSI escape + sequences). + GHCi ~~~~ ===================================== docs/users_guide/diagnostics-as-json-schema-1_2.json ===================================== @@ -0,0 +1,144 @@ +{ + "$schema": "https://json-schema.org/draft/2020-12/schema", + "title": "JSON Diagnostic Schema", + "description": "A Schema for specifying GHC diagnostics output as JSON", + "type": "object", + "properties": { + "version": { + "description": "The current JSON schema version this object conforms to", + "type": "string" + }, + "ghcVersion": { + "description": "The GHC version", + "type": "string" + }, + "span": { + "oneOf": [ + { "$ref": "#/$defs/span" }, + { "type": "null" } + ] + }, + "severity": { + "description": "The diagnostic severity", + "type": "string", + "enum": [ + "Warning", + "Error" + ] + }, + "code": { + "description": "The diagnostic code (if it exists)", + "type": [ + "integer", + "null" + ] + }, + "rendered": { + "description": "The rendered diagnostics message, in the exact same format as what GHC would have produced without -fdiagnostics-as-json (including ANSI escape sequences)", + "type": "string" + }, + "message": { + "description": "The string output of the diagnostic message by GHC", + "type": "array", + "items": { + "type": "string" + } + }, + "hints": { + "description": "The suggested fixes", + "type": "array", + "items": { + "type": "string" + } + }, + "reason" : { + "description": "The GHC flag that was responsible for the emission of the diagnostic message", + "oneOf": [ + { + "type": "object", + "description": "The diagnostic message was controlled by one or more GHC flags", + "properties": { + "flags": { + "type": "array", + "items": { + "description": "The name of a GHC flag controlling the diagnostic message", + "type": "string" + }, + "minItems": 1 + } + }, + "required": ["flags"] + }, + { + "type": "object", + "description": "The diagnostic message was controlled by a GHC diagnostic message category", + "properties": { + "category": { + "description": "The name of the GHC diagnostic message category controlling the diagnostic message", + "type": "string" + } + }, + "required": ["category"] + } + ] + } + }, + + "$comment": "NOTE: \"rendered\" is not a required field so that the schema is backward compatible with version 1.1. If you bump the schema version to 2.0 the please also add \"rendered\" to the \"required\" fields.", + "required": [ + "version", + "ghcVersion", + "span", + "severity", + "code", + "message", + "hints" + ], + + "additionalProperties": false, + "$defs": { + "span": { + "description": "The span of the diagnostic", + "type": "object", + "properties": { + "file": { + "description": "The file in which the diagnostic occurs", + "type": "string" + }, + "start": { + "description": "The start location of the diagnostic", + "$ref": "#/$defs/location" + }, + "end": { + "description": "The end location of the diagnostic", + "$ref": "#/$defs/location" + } + }, + "required": [ + "file", + "start", + "end" + ], + "additionalProperties": false + }, + "location": { + "description": "A location in a text file", + "type": "object", + "properties": { + "line": { + "description": "The line number", + "type": "integer" + }, + "column": { + "description": "The column number", + "type": "integer" + } + }, + "required": [ + "line", + "column" + ], + "additionalProperties": false + } + } +} ===================================== docs/users_guide/using.rst ===================================== @@ -1428,7 +1428,7 @@ messages and in GHCi: a new line. The structure of the output is described by a `JSON Schema https://json-schema.org/`_. - The schema can be downloaded :download:`here `. + The schema can be downloaded :download:`here `. .. ghc-flag:: -fdiagnostics-color=⟨always|auto|never⟩ :shortdesc: Use colors in error messages ===================================== testsuite/tests/driver/json.stderr ===================================== @@ -1 +1 @@ -{"version":"1.1","ghcVersion":"ghc-9.13.20250529","span":{"file":"json.hs","start":{"line":9,"column":11},"end":{"line":9,"column":21}},"severity":"Error","code":48010,"message":["Empty list of alternatives in case expression"],"hints":["Perhaps you intended to use the \u2018EmptyCase\u2019 extension"]} +{"rendered":"json.hs:9:11: error: [GHC-48010]\n Empty list of alternatives in case expression\n Suggested fix:\n Perhaps you intended to use the \u2018EmptyCase\u2019 extension\n","version":"1.1","ghcVersion":"ghc-9.13.20250627","span":{"file":"json.hs","start":{"line":9,"column":11},"end":{"line":9,"column":21}},"severity":"Error","code":48010,"message":["Empty list of alternatives in case expression"],"hints":["Perhaps you intended to use the \u2018EmptyCase\u2019 extension"]} ===================================== testsuite/tests/driver/json_warn.stderr ===================================== @@ -1,2 +1,2 @@ -{"version":"1.1","ghcVersion":"ghc-9.13.20250529","span":{"file":"json_warn.hs","start":{"line":4,"column":3},"end":{"line":4,"column":4}},"severity":"Warning","code":40910,"message":["Defined but not used: \u2018x\u2019"],"hints":[],"reason":{"flags":["unused-matches"]}} -{"version":"1.1","ghcVersion":"ghc-9.13.20250529","span":{"file":"json_warn.hs","start":{"line":7,"column":5},"end":{"line":7,"column":9}},"severity":"Warning","code":63394,"message":["In the use of \u2018head\u2019\n(imported from Prelude, but defined in GHC.Internal.List):\n\"This is a partial function, it throws an error on empty lists. Use pattern matching, 'Data.List.uncons' or 'Data.Maybe.listToMaybe' instead. Consider refactoring to use \"Data.List.NonEmpty\".\""],"hints":[],"reason":{"category":"x-partial"}} +{"rendered":"json_warn.hs:4:3: warning: [GHC-40910] [-Wunused-matches (in -Wextra)]\n Defined but not used: \u2018x\u2019\n","version":"1.1","ghcVersion":"ghc-9.13.20250627","span":{"file":"json_warn.hs","start":{"line":4,"column":3},"end":{"line":4,"column":4}},"severity":"Warning","code":40910,"message":["Defined but not used: \u2018x\u2019"],"hints":[],"reason":{"flags":["unused-matches"]}} +{"rendered":"json_warn.hs:7:5: warning: [GHC-63394] [-Wx-partial (in -Wextended-warnings)]\n In the use of \u2018head\u2019\n (imported from Prelude, but defined in GHC.Internal.List):\n \"This is a partial function, it throws an error on empty lists. Use pattern matching, 'Data.List.uncons' or 'Data.Maybe.listToMaybe' instead. Consider refactoring to use \"Data.List.NonEmpty\".\"\n","version":"1.1","ghcVersion":"ghc-9.13.20250627","span":{"file":"json_warn.hs","start":{"line":7,"column":5},"end":{"line":7,"column":9}},"severity":"Warning","code":63394,"message":["In the use of \u2018head\u2019\n(imported from Prelude, but defined in GHC.Internal.List):\n\"This is a partial function, it throws an error on empty lists. Use pattern matching, 'Data.List.uncons' or 'Data.Maybe.listToMaybe' instead. Consider refactoring to use \"Data.List.NonEmpty\".\""],"hints":[],"reason":{"category":"x-partial"}} View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/8f7994f8b58f26e2a58136ffb2267138... -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/8f7994f8b58f26e2a58136ffb2267138... You're receiving this email because of your account on gitlab.haskell.org.