luau-analyze: Add support for reading source code from stdin (#325)

Co-authored-by: Arseny Kapoulkine <arseny.kapoulkine@gmail.com>

CLI/Analyze.cpp

@@ -43,14 +43,14 @@ static void report(ReportFormat format, const char* name, const Luau::Location&
     }
 }
 
-static void reportError(ReportFormat format, const Luau::TypeError& error)
+static void reportError(Luau::Frontend& frontend, ReportFormat format, const Luau::TypeError& error)
 {
-    const char* name = error.moduleName.c_str();
+    std::string humanReadableName = frontend.fileResolver->getHumanReadableModuleName(error.moduleName);
 
     if (const Luau::SyntaxError* syntaxError = Luau::get_if<Luau::SyntaxError>(&error.data))
-        report(format, name, error.location, "SyntaxError", syntaxError->message.c_str());
+        report(format, humanReadableName.c_str(), error.location, "SyntaxError", syntaxError->message.c_str());
     else
-        report(format, name, error.location, "TypeError", Luau::toString(error).c_str());
+        report(format, humanReadableName.c_str(), error.location, "TypeError", Luau::toString(error).c_str());
 }
 
 static void reportWarning(ReportFormat format, const char* name, const Luau::LintWarning& warning)
@@ -72,14 +72,15 @@ static bool analyzeFile(Luau::Frontend& frontend, const char* name, ReportFormat
     }
 
     for (auto& error : cr.errors)
-        reportError(format, error);
+        reportError(frontend, format, error);
 
     Luau::LintResult lr = frontend.lint(name);
 
+    std::string humanReadableName = frontend.fileResolver->getHumanReadableModuleName(name);
     for (auto& error : lr.errors)
-        reportWarning(format, name, error);
+        reportWarning(format, humanReadableName.c_str(), error);
     for (auto& warning : lr.warnings)
-        reportWarning(format, name, warning);
+        reportWarning(format, humanReadableName.c_str(), warning);
 
     if (annotate)
     {
@@ -120,11 +121,25 @@ struct CliFileResolver : Luau::FileResolver
 {
     std::optional<Luau::SourceCode> readSource(const Luau::ModuleName& name) override
     {
-        std::optional<std::string> source = readFile(name);
+        Luau::SourceCode::Type sourceType;
+        std::optional<std::string> source = std::nullopt;
+
+        // If the module name is "-", then read source from stdin
+        if (name == "-")
+        {
+            source = readStdin();
+            sourceType = Luau::SourceCode::Script;
+        }
+        else
+        {
+            source = readFile(name);
+            sourceType = Luau::SourceCode::Module;
+        }
+
         if (!source)
             return std::nullopt;
 
-        return Luau::SourceCode{*source, Luau::SourceCode::Module};
+        return Luau::SourceCode{*source, sourceType};
     }
 
     std::optional<Luau::ModuleInfo> resolveModule(const Luau::ModuleInfo* context, Luau::AstExpr* node) override
@@ -143,6 +158,13 @@ struct CliFileResolver : Luau::FileResolver
 
         return std::nullopt;
     }
+
+    std::string getHumanReadableModuleName(const Luau::ModuleName& name) const override
+    {
+        if (name == "-")
+            return "stdin";
+        return name;
+    }
 };
 
 struct CliConfigResolver : Luau::ConfigResolver

CLI/FileUtils.cpp

@@ -15,6 +15,8 @@
 
 #include <string.h>
 
+#define READ_BUFFER_SIZE 4096
+
 #ifdef _WIN32
 static std::wstring fromUtf8(const std::string& path)
 {
@@ -74,6 +76,21 @@ std::optional<std::string> readFile(const std::string& name)
     return result;
 }
 
+std::optional<std::string> readStdin()
+{
+    std::string result;
+    char buffer[READ_BUFFER_SIZE] = { };
+
+    while (fgets(buffer, READ_BUFFER_SIZE, stdin) != nullptr)
+        result.append(buffer);
+
+    // If eof was not reached for stdin, then a read error occurred
+    if (!feof(stdin))
+        return std::nullopt;
+
+    return result;
+}
+
 template<typename Ch>
 static void joinPaths(std::basic_string<Ch>& str, const Ch* lhs, const Ch* rhs)
 {
@@ -190,7 +207,10 @@ bool traverseDirectory(const std::string& path, const std::function<void(const s
 bool isDirectory(const std::string& path)
 {
 #ifdef _WIN32
-    return (GetFileAttributesW(fromUtf8(path).c_str()) & FILE_ATTRIBUTE_DIRECTORY) != 0;
+    DWORD fileAttributes = GetFileAttributesW(fromUtf8(path).c_str());
+    if (fileAttributes == INVALID_FILE_ATTRIBUTES)
+        return false;
+    return (fileAttributes & FILE_ATTRIBUTE_DIRECTORY) != 0;
 #else
     struct stat st = {};
     lstat(path.c_str(), &st);
@@ -244,7 +264,9 @@ std::vector<std::string> getSourceFiles(int argc, char** argv)
 
     for (int i = 1; i < argc; ++i)
     {
-        if (argv[i][0] == '-')
+        // Treat '-' as a special file whose source is read from stdin
+        // All other arguments that start with '-' are skipped
+        if (argv[i][0] == '-' && argv[i][1] != '\0')
             continue;
 
         if (isDirectory(argv[i]))

CLI/FileUtils.h

@@ -7,6 +7,7 @@
 #include <vector>
 
 std::optional<std::string> readFile(const std::string& name);
+std::optional<std::string> readStdin();
 
 bool isDirectory(const std::string& path);
 bool traverseDirectory(const std::string& path, const std::function<void(const std::string& name)>& callback);