added lint target to Makefile

checks that linters exist before proceeding. project URL for each linter
in the Makefile comments

only go-errorlint and unconvert used at the moment

fixed all lint errors for the added linters

Makefile

@@ -19,7 +19,8 @@ endif
 
 
 ### support targets
-.PHONY: all clean tidy generate check_git check_glsl glsl_validate check_pandoc readme_spell patch_file_integrity vet
+.PHONY: all clean tidy generate glsl_validate readme_spell patch_file_integrity vet lint
+.PHONY: check_glsl check_pandoc check_awk check_linters
 
 all:
 	@echo "use 'release' to build release binary"
@@ -83,6 +84,20 @@ vet: check_awk
 	END { if (ct > 0) {exit 1} }\
 	'
 
+check_linters:
+# https://github.com/polyfloyd/go-errorlint
+ifeq (, $(shell which go-errorlint))
+	$(error "go-errorlint not installed")
+endif
+# https://github.com/mdempsky/unconvert
+ifeq (, $(shell which unconvert))
+	$(error "unconvert not installed")
+endif
+
+lint: check_linters
+	go-errorlint -c 0 -errorf -errorf-multi ./...
+	unconvert ./...
+
 ### testing targets
 .PHONY: test race race_debug fuzz
 

archivefs/path.go

@@ -301,15 +301,15 @@ func (afs *Path) Set(path string, fallback bool) error {
 				if fallback {
 					return afs.Set(prevSearch, false)
 				}
-				return fmt.Errorf("archivefs: set: %v", err)
+				return fmt.Errorf("archivefs: set: %w", err)
 			}
 
 			zfi, err := zf.Stat()
 			if err != nil {
 				if fallback {
 					return afs.Set(prevSearch, false)
 				}
-				return fmt.Errorf("archivefs: set: %v", err)
+				return fmt.Errorf("archivefs: set: %w", err)
 			}
 
 			afs.isDir = zfi.IsDir()
@@ -326,7 +326,7 @@ func (afs *Path) Set(path string, fallback bool) error {
 				if fallback {
 					return afs.Set(prevSearch, false)
 				}
-				return fmt.Errorf("archivefs: set: %v", err)
+				return fmt.Errorf("archivefs: set: %w", err)
 			}
 
 			afs.isDir = fi.IsDir()
@@ -345,7 +345,7 @@ func (afs *Path) Set(path string, fallback bool) error {
 				if fallback {
 					return afs.Set(prevSearch, false)
 				}
-				return fmt.Errorf("archivefs: set: %v", err)
+				return fmt.Errorf("archivefs: set: %w", err)
 			}
 		}
 	}
@@ -355,7 +355,7 @@ func (afs *Path) Set(path string, fallback bool) error {
 	var err error
 	afs.current, err = filepath.Abs(search)
 	if err != nil {
-		return fmt.Errorf("archivefs: set: %v", err)
+		return fmt.Errorf("archivefs: set: %w", err)
 	}
 
 	// make sure path is clean

coprocessor/developer/developer.go

@@ -390,7 +390,7 @@ func (dev *Developer) SearchStaticMemory(output io.Writer, data uint32, width in
 				if !ok {
 					return fmt.Errorf("address %08x not found in segment (it should be)", addr)
 				}
-				if v == uint32(data) {
+				if v == data {
 					output.Write([]byte(fmt.Sprintf("%s %08x", seg.Name, addr)))
 				}
 			}

coprocessor/developer/dwarf/dwarf_builder.go

@@ -75,7 +75,7 @@ func newBuild(dwrf *dwarf.Data, debug_loc *loclistSection, debug_frame *frameSec
 	for {
 		entry, err := r.Next()
 		if err != nil {
-			if err == io.EOF {
+			if errors.Is(err, io.EOF) {
 				break // for loop
 			}
 			return nil, err
@@ -591,7 +591,7 @@ func (bld *build) buildVariables(src *Source, ef *elf.File,
 
 			fld := e.AttrField(dwarf.AttrLowpc)
 			if fld != nil {
-				compilationUnitAddress += uint64(fld.Val.(uint64))
+				compilationUnitAddress += fld.Val.(uint64)
 			}
 
 			continue // for loop
@@ -605,7 +605,7 @@ func (bld *build) buildVariables(src *Source, ef *elf.File,
 
 			fld := e.AttrField(dwarf.AttrLowpc)
 			if fld != nil {
-				low = addressAdjustment + uint64(fld.Val.(uint64))
+				low = addressAdjustment + fld.Val.(uint64)
 
 				fld = e.AttrField(dwarf.AttrHighpc)
 				if fld == nil {
@@ -618,7 +618,7 @@ func (bld *build) buildVariables(src *Source, ef *elf.File,
 					high = low + uint64(fld.Val.(int64))
 				case dwarf.ClassAddress:
 					// dwarf-2
-					high = uint64(fld.Val.(uint64))
+					high = fld.Val.(uint64)
 				default:
 				}
 
@@ -1036,7 +1036,7 @@ func (bld *build) buildFunctions(src *Source, addressAdjustment uint64) error {
 			// 2.17.3)."
 			fld := e.AttrField(dwarf.AttrLowpc)
 			if fld != nil {
-				compilationUnitAddress += uint64(fld.Val.(uint64))
+				compilationUnitAddress += fld.Val.(uint64)
 			}
 		case dwarf.TagSubprogram:
 			// check address against low/high fields
@@ -1050,7 +1050,7 @@ func (bld *build) buildFunctions(src *Source, addressAdjustment uint64) error {
 				// either concrete Subprograms or concrete InlinedSubroutines
 				continue // for loop
 			}
-			low = addressAdjustment + uint64(fld.Val.(uint64))
+			low = addressAdjustment + fld.Val.(uint64)
 
 			fld = e.AttrField(dwarf.AttrHighpc)
 			if fld == nil {
@@ -1063,7 +1063,7 @@ func (bld *build) buildFunctions(src *Source, addressAdjustment uint64) error {
 				high = low + uint64(fld.Val.(int64))
 			case dwarf.ClassAddress:
 				// dwarf-2
-				high = uint64(fld.Val.(uint64))
+				high = fld.Val.(uint64)
 			default:
 				return fmt.Errorf("AttrLowpc without AttrHighpc for Subprogram")
 			}
@@ -1170,7 +1170,7 @@ func (bld *build) buildFunctions(src *Source, addressAdjustment uint64) error {
 
 			fld := e.AttrField(dwarf.AttrLowpc)
 			if fld != nil {
-				low = addressAdjustment + uint64(fld.Val.(uint64))
+				low = addressAdjustment + fld.Val.(uint64)
 
 				// high PC
 				fld = e.AttrField(dwarf.AttrHighpc)
@@ -1184,7 +1184,7 @@ func (bld *build) buildFunctions(src *Source, addressAdjustment uint64) error {
 					high = low + uint64(fld.Val.(int64))
 				case dwarf.ClassAddress:
 					// dwarf-2
-					high = uint64(fld.Val.(uint64))
+					high = fld.Val.(uint64)
 				default:
 					return fmt.Errorf("AttrLowpc without AttrHighpc for InlinedSubroutine")
 				}

coprocessor/developer/dwarf/dwarf_frame_instructions.go

@@ -166,7 +166,7 @@ func decodeFrameInstruction(coproc coprocessor.CartCoProc, byteOrder binary.Byte
 			if int(reg) >= len(tab.rows[0].registers) {
 				// ignore extended registers for now
 			} else {
-				tab.rows[0].registers[reg].value = int64(offset) * cie.dataAlignment
+				tab.rows[0].registers[reg].value = offset * cie.dataAlignment
 			}
 
 			return frameInstruction{
@@ -477,7 +477,7 @@ func decodeFrameInstruction(coproc coprocessor.CartCoProc, byteOrder binary.Byte
 		if int(reg) >= len(tab.rows[0].registers) {
 			err = fmt.Errorf("bad register %d", reg)
 		} else {
-			tab.rows[0].registers[reg].value = int64(offset)
+			tab.rows[0].registers[reg].value = offset
 		}
 
 		return frameInstruction{

coprocessor/developer/dwarf/leb128/leb128.go

@@ -48,7 +48,7 @@ func DecodeSLEB128(encoded []uint8) (int64, int) {
 	var n int
 	for _, v = range encoded {
 		n++
-		result |= int64((int64(v) & 0x7f) << shift)
+		result |= (int64(v) & 0x7f) << shift
 		shift += 7
 		if v&0x80 == 0x00 {
 			break
@@ -60,5 +60,5 @@ func DecodeSLEB128(encoded []uint8) (int64, int) {
 		result |= -(1 << shift)
 	}
 
-	return int64(result), n
+	return result, n
 }

coprocessor/developer/dwarf/source.go

@@ -203,7 +203,7 @@ func NewSource(romFile string, cart Cartridge, elfFile string) (*Source, error)
 	}
 	b, err := debug_info.Data()
 	if err != nil {
-		return nil, fmt.Errorf("dwarf: %v", err)
+		return nil, fmt.Errorf("dwarf: %w", err)
 	}
 	version := ef.ByteOrder.Uint16(b[4:])
 	if version != 4 {
@@ -302,7 +302,7 @@ func NewSource(romFile string, cart Cartridge, elfFile string) (*Source, error)
 
 		// if ELF file was manually specified prefer
 		if elfFile != "" {
-			addressAdjustment = uint64(ef.Entry)
+			addressAdjustment = ef.Entry
 			adjust = true
 		} else {
 			if c, ok := bus.(coprocessor.CartCoProcOrigin); ok {
@@ -399,7 +399,7 @@ func NewSource(romFile string, cart Cartridge, elfFile string) (*Source, error)
 	for {
 		e, err := r.Next()
 		if err != nil {
-			if err == io.EOF {
+			if errors.Is(err, io.EOF) {
 				break // for loop
 			}
 			return nil, fmt.Errorf("dwarf: %w", err)
@@ -421,7 +421,7 @@ func NewSource(romFile string, cart Cartridge, elfFile string) (*Source, error)
 
 			fld := e.AttrField(dwarf.AttrLowpc)
 			if fld != nil {
-				unit.address = addressAdjustment + uint64(fld.Val.(uint64))
+				unit.address = addressAdjustment + fld.Val.(uint64)
 			}
 
 			// assuming DWARF never has duplicate compile unit entries
@@ -604,7 +604,7 @@ func allocateSourceLines(src *Source, dwrf *dwarf.Data, addressAdjustment uint64
 		for {
 			err := r.Next(&le)
 			if err != nil {
-				if err == io.EOF {
+				if errors.Is(err, io.EOF) {
 					break // line entry for loop. will continue with compile unit loop
 				}
 				return err
@@ -680,7 +680,7 @@ func allocateSourceLines(src *Source, dwrf *dwarf.Data, addressAdjustment uint64
 		for {
 			err := r.Next(&le)
 			if err != nil {
-				if err == io.EOF {
+				if errors.Is(err, io.EOF) {
 					break // line entry for loop. will continue with compile unit loop
 				}
 				return err
@@ -841,12 +841,12 @@ func addFunctionStubs(src *Source, ef *elf.File) error {
 		if typ == 0x02 {
 			// align address
 			// TODO: this is a bit of ARM specific knowledge that should be removed
-			a := uint64(s.Value & 0xfffffffe)
+			a := s.Value & 0xfffffffe
 			symbolTableFunctions = append(symbolTableFunctions, fn{
 				name: s.Name,
 				rng: SourceRange{
 					Start: a,
-					End:   a + uint64(s.Size) - 1,
+					End:   a + s.Size - 1,
 				},
 			})
 		}

database/session.go

@@ -78,8 +78,8 @@ func StartSession(path string, activity Activity, init func(*Session) error) (*S
 
 	db.dbfile, err = os.OpenFile(path, flags, 0600)
 	if err != nil {
-		switch err.(type) {
-		case *os.PathError:
+		var pathError *os.PathError
+		if errors.As(err, &pathError) {
 			return nil, fmt.Errorf("%w: %s", NotAvailable, path)
 		}
 		return nil, fmt.Errorf("database: %w", err)

debugger/commands.go

@@ -662,7 +662,7 @@ func (dbg *Debugger) processTokens(tokens *commandline.Tokens) error {
 
 				var ok bool
 
-				ln, ok = src.LinesByAddress[uint64(addr)]
+				ln, ok = src.LinesByAddress[addr]
 				if !ok {
 					dbg.printLine(terminal.StyleError, fmt.Sprintf("address %x does not correspond to a source line", addr))
 				} else {

debugger/halt_targets.go

@@ -140,7 +140,7 @@ func parseTarget(dbg *Debugger, tokens *commandline.Tokens) (*target, error) {
 			trg = &target{
 				label: "RDY",
 				value: func() targetValue {
-					return bool(dbg.vcs.CPU.RdyFlg)
+					return dbg.vcs.CPU.RdyFlg
 				},
 				format:              "%v",
 				instructionBoundary: true,

debugger/terminal/colorterm/easyterm/easyterm.go

@@ -126,7 +126,7 @@ func (et *EasyTerm) UpdateGeometry() error {
 		uintptr(unsafe.Pointer(&et.geometry)))
 
 	if errno != 0 {
-		return fmt.Errorf("error updating terminal geometry information (%d)", errno)
+		return fmt.Errorf("error updating terminal geometry information (%w)", errno)
 	}
 
 	return nil

gopher2600.go

@@ -226,7 +226,7 @@ func launch(sync *mainSync, args []string) {
 	// execution modes summary and return
 	err := flgs.Parse(args)
 	if err != nil {
-		if err == flag.ErrHelp {
+		if errors.Is(err, flag.ErrHelp) {
 			fmt.Println("Execution Modes: RUN, DEBUG, DISASM, PERFORMANCE, REGRESS, VERSION")
 			sync.state <- stateRequest{req: reqQuit, args: 20}
 			return
@@ -616,7 +616,7 @@ func regress(mode string, args []string) error {
 	flgs := flag.NewFlagSet(mode, flag.ContinueOnError)
 	err := flgs.Parse(args)
 	if err != nil {
-		if err == flag.ErrHelp {
+		if errors.Is(err, flag.ErrHelp) {
 			fmt.Println("Sub modes: RUN, LIST, DELETE, ADD, REDUX, CLEANUP")
 		}
 		return nil
@@ -749,7 +749,7 @@ func regressAdd(mode string, args []string) error {
 	// parse args and get copy of remaining arguments
 	err := flgs.Parse(args)
 	if err != nil {
-		if err == flag.ErrHelp {
+		if errors.Is(err, flag.ErrHelp) {
 			fmt.Println()
 			fmt.Println(`The regression test to be added can be the path to a cartridge file or a previously
 recorded playback file. For playback files, the flags marked [not playback files] do not

gui/sdlimgui/imgui_helpers.go

@@ -529,7 +529,7 @@ func drawRegister(id string, val uint8, mask uint8, col imgui.PackedColor, onWri
 			if seq.rectFill(col) {
 				v := val ^ (0x80 >> i)
 				if onWrite != nil {
-					onWrite(uint8(v & mask))
+					onWrite(v & mask)
 				}
 			}
 		} else {

gui/sdlimgui/manager_hotkeys.go

@@ -17,6 +17,7 @@ package sdlimgui
 
 import (
 	"bufio"
+	"errors"
 	"fmt"
 	"os"
 	"strings"
@@ -93,8 +94,8 @@ func (wm *manager) loadManagerHotkeys() (rerr error) {
 	// open an existing hotkeys file
 	f, err := fs.Open(pth)
 	if err != nil {
-		switch err.(type) {
-		case *os.PathError:
+		var pathError *os.PathError
+		if errors.As(err, &pathError) {
 			return nil
 		}
 		return fmt.Errorf("manager hotkeys: %w", err)

gui/sdlimgui/manager_state.go

@@ -17,6 +17,7 @@ package sdlimgui
 
 import (
 	"bufio"
+	"errors"
 	"fmt"
 	"os"
 	"strings"
@@ -121,8 +122,8 @@ func (wm *manager) loadManagerState() (rerr error) {
 	// open an existing state file
 	f, err := fs.Open(pth)
 	if err != nil {
-		switch err.(type) {
-		case *os.PathError:
+		var pathError *os.PathError
+		if errors.As(err, &pathError) {
 			return nil
 		}
 		return fmt.Errorf("manager state: %w", err)

gui/sdlimgui/win_cart_static.go

@@ -201,7 +201,7 @@ func (win *winCartStatic) draw(static mapper.CartStatic) {
 									switch varb.Type.Size {
 									case 4:
 										if d, ok := currStatic.Read32bit(addr); ok {
-											value = uint32(d)
+											value = d
 											currValue = fmt.Sprintf("%08x", d)
 										}
 										if d, ok := compStatic.Read32bit(addr); ok {