add built-in report formats incl. GitHub Actions

use on ourself and enable unused variables test to do first test in CI

.dscanner.ini

@@ -23,7 +23,7 @@ if_else_same_check="enabled"
 ; Checks for some problems with constructors
 constructor_check="enabled"
 ; Checks for unused variables and function parameters
-unused_variable_check="disabled"
+unused_variable_check="enabled"
 ; Checks for unused labels
 unused_label_check="enabled"
 ; Checks for duplicate attributes

.github/workflows/default.yml

@@ -135,7 +135,7 @@ jobs:
           else
             EXE=""
           fi
-          "./bin/dscanner$EXE" --config .dscanner.ini --styleCheck src
+          "./bin/dscanner$EXE" --config .dscanner.ini --styleCheck -f github src
 
       # Parse phobos to check for failures / crashes / ...
       - name: Checkout Phobos

src/dscanner/analysis/run.d

@@ -101,6 +101,16 @@ private alias ASTAllocator = CAllocatorImpl!(
 
 immutable string defaultErrorFormat = "{filepath}({line}:{column})[{type}]: {message}";
 
+string[string] errorFormatMap()
+{
+	static string[string] ret;
+	if (ret is null)
+		ret = [
+			"github": "::{type2} file={filepath},line={line},endLine={endLine},col={column},endColumn={endColumn},title={Type2} ({name})::{message}"
+		];
+	return ret;
+}
+
 void messageFunctionFormat(string format, Message message, bool isError)
 {
 	auto s = format;
@@ -111,6 +121,11 @@ void messageFunctionFormat(string format, Message message, bool isError)
 	s = s.replace("{endLine}", to!string(message.endLine));
 	s = s.replace("{endColumn}", to!string(message.endColumn));
 	s = s.replace("{type}", isError ? "error" : "warn");
+	s = s.replace("{Type}", isError ? "Error" : "Warn");
+	s = s.replace("{TYPE}", isError ? "ERROR" : "WARN");
+	s = s.replace("{type2}", isError ? "error" : "warning");
+	s = s.replace("{Type2}", isError ? "Error" : "Warning");
+	s = s.replace("{TYPE2}", isError ? "ERROR" : "WARNING");
 	s = s.replace("{message}", message.message);
     s = s.replace("{name}", message.checkName);
 

src/dscanner/main.d

@@ -167,6 +167,8 @@ else
 
 	if (!errorFormat.length)
 		errorFormat = defaultErrorFormat;
+	else if (auto errorFormatSuppl = errorFormat in errorFormatMap)
+		errorFormat = *errorFormatSuppl;
 
 	const(string[]) absImportPaths = importPaths.map!(a => a.absolutePath()
 			.buildNormalizedPath()).array();
@@ -405,8 +407,22 @@ Options:
     --errorFormat|f <pattern>
         Format errors produced by the style/syntax checkers. The default
         value for the pattern is: "%2$s".
-        Supported placeholders are: {filepath}, {line}, {column}, {type},
-        {endLine}, {endColumn}, {message}, and {name}.
+
+        Supported placeholders are:
+        - {filepath}: file path, usually relative to CWD
+        - {line}: start line number, 1-based
+        - {endLine}: end line number, 1-based, inclusive
+        - {column}: start column on start line, 1-based, in bytes
+        - {endColumn}: end column on end line, 1-based, in bytes, exclusive
+        - {type}: "error" or "warn", uppercase variants: {Type}, {TYPE},
+        - {type2}: "error" or "warning", uppercase variants: {Type2}, {TYPE2}
+        - {message}: human readable message such as "Variable c is never used."
+        - {name}: D-Scanner check name such as "unused_variable_check"
+
+        For compatibility with other tools, the following strings may be
+        specified as shorthand aliases:
+
+        %3$(-f %1$s -> %2$s\n        %)
 
     --ctags <file | directory>..., -c <file | directory>...
         Generates ctags information from the given source code file. Note that
@@ -453,7 +469,7 @@ Options:
         Does not analyze code in unittests. Only works if --styleCheck
         is specified.`,
 
-    programName, defaultErrorFormat);
+    programName, defaultErrorFormat, errorFormatMap);
 }
 
 private void doNothing(string, size_t, size_t, string, bool)