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src,lib: print source map error source on demand
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The source context is not prepended to the value of the `stack` property
when the source map is not enabled. Rather than prepending the error
source context to the value of the `stack` property unconditionally,
this patch aligns the behavior and only prints the source context when
the error is not handled by userland (e.g. fatal errors).

Also, this patch fixes that when source-map support is enabled, the
error source context is not pointing to where the error was thrown.
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@legendecas
legendecas committed Jul 21, 2022
1 parent 71ca6d7 commit 1ef283d
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Showing 14 changed files with 152 additions and 87 deletions.
44 changes: 26 additions & 18 deletions lib/internal/source_map/prepare_stack_trace.js
View file
Original file line number Diff line number Diff line change
Expand Up @@ -25,6 +25,7 @@ const {
kIsNodeError,
} = require('internal/errors');
const { fileURLToPath } = require('internal/url');
const { setGetSourceMapErrorSource } = internalBinding('errors');

// Create a prettified stacktrace, inserting context from source maps
// if possible.
Expand Down Expand Up @@ -53,7 +54,6 @@ const prepareStackTrace = (globalThis, error, trace) => {
return errorString;
}

let errorSource = '';
let lastSourceMap;
let lastFileName;
const preparedTrace = ArrayPrototypeJoin(ArrayPrototypeMap(trace, (t, i) => {
Expand All @@ -62,14 +62,12 @@ const prepareStackTrace = (globalThis, error, trace) => {
// A stack trace will often have several call sites in a row within the
// same file, cache the source map and file content accordingly:
let fileName = t.getFileName();
let generated = false;
if (fileName === undefined) {
fileName = t.getEvalOrigin();
generated = true;
}
const sm = fileName === lastFileName ?
lastSourceMap :
findSourceMap(fileName, generated);
findSourceMap(fileName);
lastSourceMap = sm;
lastFileName = fileName;
if (sm) {
Expand All @@ -83,14 +81,6 @@ const prepareStackTrace = (globalThis, error, trace) => {
if (originalSource && originalLine !== undefined &&
originalColumn !== undefined) {
const name = getOriginalSymbolName(sm, trace, i);
if (i === 0) {
errorSource = getErrorSource(
sm,
originalSource,
originalLine,
originalColumn
);
}
// Construct call site name based on: v8.dev/docs/stack-trace-api:
const fnName = t.getFunctionName() ?? t.getMethodName();
const typeName = t.getTypeName();
Expand All @@ -116,7 +106,7 @@ const prepareStackTrace = (globalThis, error, trace) => {
}
return `${str}${t}`;
}), '');
return `${errorSource}${errorString}\n at ${preparedTrace}`;
return `${errorString}\n at ${preparedTrace}`;
};

// Transpilers may have removed the original symbol name used in the stack
Expand Down Expand Up @@ -155,7 +145,7 @@ function getErrorSource(
fileURLToPath(originalSourcePath) : originalSourcePath;
const source = getOriginalSource(
sourceMap.payload,
originalSourcePathNoScheme
originalSourcePath
);
const lines = RegExpPrototypeSymbolSplit(/\r?\n/, source, originalLine + 1);
const line = lines[originalLine];
Expand All @@ -178,28 +168,46 @@ function getErrorSource(

function getOriginalSource(payload, originalSourcePath) {
let source;
const originalSourcePathNoScheme =
StringPrototypeStartsWith(originalSourcePath, 'file://') ?
fileURLToPath(originalSourcePath) : originalSourcePath;
// payload.sources has been normalized to be an array of absolute urls.
const sourceContentIndex =
ArrayPrototypeIndexOf(payload.sources, originalSourcePath);
if (payload.sourcesContent?.[sourceContentIndex]) {
// First we check if the original source content was provided in the
// source map itself:
source = payload.sourcesContent[sourceContentIndex];
} else {
} else if (StringPrototypeStartsWith(originalSourcePath, 'file://')) {
// If no sourcesContent was found, attempt to load the original source
// from disk:
debug(`read source of ${originalSourcePath} from filesystem`);
const originalSourcePathNoScheme = fileURLToPath(originalSourcePath);
try {
source = readFileSync(originalSourcePathNoScheme, 'utf8');
} catch (err) {
debug(err);
source = '';
}
} else {
source = '';
}
return source;
}

function getSourceMapErrorSource(fileName, lineNumber, columnNumber) {
const sm = findSourceMap(fileName);
if (sm === null) {
return;
}
const {
originalLine,
originalColumn,
originalSource,
} = sm.findEntry(lineNumber - 1, columnNumber);
const errorSource = getErrorSource(sm, originalSource, originalLine, originalColumn);
return errorSource;
}

setGetSourceMapErrorSource(getSourceMapErrorSource);

module.exports = {
prepareStackTrace,
};
91 changes: 54 additions & 37 deletions lib/internal/source_map/source_map_cache.js
View file
Original file line number Diff line number Diff line change
Expand Up @@ -41,6 +41,8 @@ const esmSourceMapCache = new SafeMap();
// The generated sources is not mutable, so we can use a Map without memory concerns:
const generatedSourceMapCache = new SafeMap();
const kLeadingProtocol = /^\w+:\/\//;
const kSourceMappingURLMagicComment = /\/[*/]#\s+sourceMappingURL=(?<sourceMappingURL>[^\s]+)/;
const kSourceURLMagicComment = /\/[*/]#\s+sourceURL=(?<sourceURL>[^\s]+)/;

const { fileURLToPath, pathToFileURL, URL } = require('internal/url');
let SourceMap;
Expand Down Expand Up @@ -77,7 +79,22 @@ function setSourceMapsEnabled(val) {
sourceMapsEnabled = val;
}

function maybeCacheSourceMap(filename, content, cjsModuleInstance, isGeneratedSource) {
function extractSourceURLMagicComment(content) {
const matchSourceURL = RegExpPrototypeExec(
kSourceURLMagicComment,
content
);
if (matchSourceURL === null) {
return null;
}
let sourceURL = matchSourceURL.groups.sourceURL;
if (sourceURL != null && RegExpPrototypeExec(kLeadingProtocol, sourceURL) === null) {
sourceURL = pathToFileURL(sourceURL).href;
}
return sourceURL;
}

function maybeCacheSourceMap(filename, content, cjsModuleInstance, isGeneratedSource, sourceURL) {
const sourceMapsEnabled = getSourceMapsEnabled();
if (!(process.env.NODE_V8_COVERAGE || sourceMapsEnabled)) return;
try {
Expand All @@ -87,10 +104,10 @@ function maybeCacheSourceMap(filename, content, cjsModuleInstance, isGeneratedSo
debug(err);
return;
}
const match = RegExpPrototypeExec(
/\/[*/]#\s+sourceMappingURL=(?<sourceMappingURL>[^\s]+)/,
content,
);
const match = RegExpPrototypeExec(kSourceMappingURLMagicComment, content);
if (sourceURL === undefined) {
sourceURL = extractSourceURLMagicComment(content);
}
if (match) {
const data = dataFromUrl(filename, match.groups.sourceMappingURL);
const url = data ? null : match.groups.sourceMappingURL;
Expand All @@ -99,22 +116,33 @@ function maybeCacheSourceMap(filename, content, cjsModuleInstance, isGeneratedSo
filename,
lineLengths: lineLengths(content),
data,
url
url,
sourceURL,
});
} else if (isGeneratedSource) {
generatedSourceMapCache.set(filename, {
const entry = {
lineLengths: lineLengths(content),
data,
url
});
url,
sourceURL
};
generatedSourceMapCache.set(filename, entry);
if (sourceURL) {
generatedSourceMapCache.set(sourceURL, entry);
}
} else {
// If there is no cjsModuleInstance and is not generated source assume we are in a
// "modules/esm" context.
esmSourceMapCache.set(filename, {
const entry = {
lineLengths: lineLengths(content),
data,
url
});
url,
sourceURL,
};
esmSourceMapCache.set(filename, entry);
if (sourceURL) {
esmSourceMapCache.set(sourceURL, entry);
}
}
}
}
Expand All @@ -123,19 +151,12 @@ function maybeCacheGeneratedSourceMap(content) {
const sourceMapsEnabled = getSourceMapsEnabled();
if (!(process.env.NODE_V8_COVERAGE || sourceMapsEnabled)) return;

const matchSourceURL = RegExpPrototypeExec(
/\/[*/]#\s+sourceURL=(?<sourceURL>[^\s]+)/,
content
);
if (matchSourceURL == null) {
const sourceURL = extractSourceURLMagicComment(content);
if (sourceURL === null) {
return;
}
let sourceURL = matchSourceURL.groups.sourceURL;
if (RegExpPrototypeExec(kLeadingProtocol, sourceURL) === null) {
sourceURL = pathToFileURL(sourceURL).href;
}
try {
maybeCacheSourceMap(sourceURL, content, null, true);
maybeCacheSourceMap(sourceURL, content, null, true, sourceURL);
} catch (err) {
// This can happen if the filename is not a valid URL.
// If we fail to cache the source map, we should not fail the whole process.
Expand Down Expand Up @@ -254,33 +275,29 @@ function appendCJSCache(obj) {
}
}

function findSourceMap(sourceURL, isGenerated) {
function findSourceMap(sourceURL) {
if (RegExpPrototypeExec(kLeadingProtocol, sourceURL) === null) {
sourceURL = pathToFileURL(sourceURL).href;
}
if (!SourceMap) {
SourceMap = require('internal/source_map/source_map').SourceMap;
}
let sourceMap;
if (isGenerated) {
sourceMap = generatedSourceMapCache.get(sourceURL);
} else {
sourceMap = esmSourceMapCache.get(sourceURL);
if (sourceMap === undefined) {
for (const value of cjsSourceMapCache) {
const filename = ObjectGetValueSafe(value, 'filename');
if (sourceURL === filename) {
sourceMap = {
data: ObjectGetValueSafe(value, 'data')
};
}
let sourceMap = esmSourceMapCache.get(sourceURL) ?? generatedSourceMapCache.get(sourceURL);
if (sourceMap === undefined) {
for (const value of cjsSourceMapCache) {
const filename = ObjectGetValueSafe(value, 'filename');
const cachedSourceURL = ObjectGetValueSafe(value, 'sourceURL');
if (sourceURL === filename || sourceURL === cachedSourceURL) {
sourceMap = {
data: ObjectGetValueSafe(value, 'data')
};
}
}
}
if (sourceMap && sourceMap.data) {
return new SourceMap(sourceMap.data);
}
return undefined;
return null;
}

module.exports = {
Expand Down
1 change: 1 addition & 0 deletions src/env.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -525,6 +525,7 @@ class NoArrayBufferZeroFillScope {
V(enhance_fatal_stack_after_inspector, v8::Function) \
V(enhance_fatal_stack_before_inspector, v8::Function) \
V(fs_use_promises_symbol, v8::Symbol) \
V(get_source_map_error_source, v8::Function) \
V(host_import_module_dynamically_callback, v8::Function) \
V(host_initialize_import_meta_object_callback, v8::Function) \
V(http2session_on_altsvc_function, v8::Function) \
Expand Down
56 changes: 51 additions & 5 deletions src/node_errors.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -49,6 +49,40 @@ namespace per_process {
static Mutex tty_mutex;
} // namespace per_process

static std::string GetSourceMapErrorSource(Isolate* isolate,
Local<Context> context,
Local<Message> message,
bool* added_exception_line) {
v8::TryCatch try_catch(isolate);
HandleScope handle_scope(isolate);
Environment* env = Environment::GetCurrent(context);

// The ScriptResourceName of the message may be different from the one we use
// to compile the script. V8 replaces it when it detects magic comments in
// the source texts.
Local<Value> script_resource_name = message->GetScriptResourceName();
int linenum = message->GetLineNumber(context).FromJust();
int columnum = message->GetStartColumn(context).FromJust();

Local<Value> argv[] = {script_resource_name,
v8::Int32::New(isolate, linenum),
v8::Int32::New(isolate, columnum)};
MaybeLocal<Value> maybe_ret = env->get_source_map_error_source()->Call(
context, Undefined(isolate), arraysize(argv), argv);
Local<Value> ret;
if (!maybe_ret.ToLocal(&ret)) {
// Ignore the caught exceptions.
DCHECK(try_catch.HasCaught());
return std::string();
}
if (!ret->IsString()) {
return std::string();
}
*added_exception_line = true;
node::Utf8Value error_source_utf8(isolate, ret.As<String>());
return *error_source_utf8;
}

static std::string GetErrorSource(Isolate* isolate,
Local<Context> context,
Local<Message> message,
Expand All @@ -58,17 +92,19 @@ static std::string GetErrorSource(Isolate* isolate,
std::string sourceline(*encoded_source, encoded_source.length());
*added_exception_line = false;

if (sourceline.find("node-do-not-add-exception-line") != std::string::npos) {
return sourceline;
}

// If source maps have been enabled, the exception line will instead be
// added in the JavaScript context:
Environment* env = Environment::GetCurrent(isolate);
const bool has_source_map_url =
!message->GetScriptOrigin().SourceMapUrl().IsEmpty();
if (has_source_map_url && env != nullptr && env->source_maps_enabled()) {
return sourceline;
}

if (sourceline.find("node-do-not-add-exception-line") != std::string::npos) {
return sourceline;
std::string source = GetSourceMapErrorSource(
isolate, context, message, added_exception_line);
return added_exception_line ? source : sourceline;
}

// Because of how node modules work, all scripts are wrapped with a
Expand Down Expand Up @@ -868,6 +904,13 @@ static void SetSourceMapsEnabled(const FunctionCallbackInfo<Value>& args) {
env->set_source_maps_enabled(args[0].As<Boolean>()->Value());
}

static void SetGetSourceMapErrorSource(
const FunctionCallbackInfo<Value>& args) {
Environment* env = Environment::GetCurrent(args);
CHECK(args[0]->IsFunction());
env->set_get_source_map_error_source(args[0].As<Function>());
}

static void SetMaybeCacheGeneratedSourceMap(
const FunctionCallbackInfo<Value>& args) {
Environment* env = Environment::GetCurrent(args);
Expand Down Expand Up @@ -908,6 +951,7 @@ static void TriggerUncaughtException(const FunctionCallbackInfo<Value>& args) {

void RegisterExternalReferences(ExternalReferenceRegistry* registry) {
registry->Register(SetPrepareStackTraceCallback);
registry->Register(SetGetSourceMapErrorSource);
registry->Register(SetSourceMapsEnabled);
registry->Register(SetMaybeCacheGeneratedSourceMap);
registry->Register(SetEnhanceStackForFatalException);
Expand All @@ -922,6 +966,8 @@ void Initialize(Local<Object> target,
Environment* env = Environment::GetCurrent(context);
env->SetMethod(
target, "setPrepareStackTraceCallback", SetPrepareStackTraceCallback);
env->SetMethod(
target, "setGetSourceMapErrorSource", SetGetSourceMapErrorSource);
env->SetMethod(target, "setSourceMapsEnabled", SetSourceMapsEnabled);
env->SetMethod(target,
"setMaybeCacheGeneratedSourceMap",
Expand Down
6 changes: 5 additions & 1 deletion test/message/source_map_disabled_by_api.js
View file
Original file line number Diff line number Diff line change
Expand Up @@ -17,4 +17,8 @@ delete require.cache[require
// Re-enable.
process.setSourceMapsEnabled(true);

require('../fixtures/source-map/enclosing-call-site-min.js');
try {
require('../fixtures/source-map/enclosing-call-site-min.js');
} catch (e) {
console.log(e);
}
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