all: fix some issues spotted by static analysis

First, vet was upset by two incorrect fmt verbs. One was an extra %x,
when there was just one argument, so remove it. Another was a %p with a
non-pointer. It's a struct, so for now simply use %#v.

Second, staticcheck found some unused or unnecessary bits of code;
remove the obvious ones.

Finally, staticcheck also complained about some error strings which were
capitalized or had periods. Adjust those, which also makes all error
messages more consistent.

Signed-off-by: Daniel Martí <mvdan@mvdan.cc>

apps/gophers/ui.go

@@ -58,7 +58,6 @@ type UI struct {
 }
 
 type userPage struct {
-	config      ui.Config
 	faces       measure.Faces
 	user        *user
 	commitsList *layout.List

cmd/gio/androidbuild.go

@@ -38,7 +38,7 @@ type errWriter struct {
 func buildAndroid(tmpDir string, bi *buildInfo) error {
 	sdk := os.Getenv("ANDROID_HOME")
 	if sdk == "" {
-		return errors.New("Please set ANDROID_HOME to the Android SDK path")
+		return errors.New("please set ANDROID_HOME to the Android SDK path")
 	}
 	if _, err := os.Stat(sdk); err != nil {
 		return err
@@ -75,11 +75,11 @@ func buildAndroid(tmpDir string, bi *buildInfo) error {
 func compileAndroid(tmpDir string, tools *androidTools, bi *buildInfo) (err error) {
 	androidHome := os.Getenv("ANDROID_HOME")
 	if androidHome == "" {
-		return errors.New("ANDROID_HOME is not set. Please point it to the root of the Android SDK.")
+		return errors.New("ANDROID_HOME is not set. Please point it to the root of the Android SDK")
 	}
 	ndkRoot := filepath.Join(androidHome, "ndk-bundle")
 	if _, err := os.Stat(ndkRoot); err != nil {
-		return fmt.Errorf("No NDK found in $ANDROID_HOME/ndk-bundle (%s). Use `sdkmanager ndk-bundle` to install it.", ndkRoot)
+		return fmt.Errorf("no NDK found in $ANDROID_HOME/ndk-bundle (%s). Use `sdkmanager ndk-bundle` to install it", ndkRoot)
 	}
 	tcRoot := filepath.Join(ndkRoot, "toolchains", "llvm", "prebuilt", archNDK())
 	var builds errgroup.Group
@@ -87,7 +87,7 @@ func compileAndroid(tmpDir string, tools *androidTools, bi *buildInfo) (err erro
 		arch := allArchs[a]
 		clang := filepath.Join(tcRoot, "bin", arch.clang)
 		if _, err := os.Stat(clang); err != nil {
-			return fmt.Errorf("No NDK compiler found. Please make sure you have NDK >= r19c installed. Use the command `sdkmanager ndk-bundle` to install it. Path %s", clang)
+			return fmt.Errorf("no NDK compiler found. Please make sure you have NDK >= r19c installed. Use the command `sdkmanager ndk-bundle` to install it. Path %s", clang)
 		}
 		if runtime.GOOS == "windows" {
 			// Because of https://github.com/android-ndk/ndk/issues/920,
@@ -95,7 +95,7 @@ func compileAndroid(tmpDir string, tools *androidTools, bi *buildInfo) (err erro
 			// clang++.cmd which is only available in r19c.
 			clangpp := filepath.Join(tcRoot, "bin", arch.clang+"++.cmd")
 			if _, err := os.Stat(clangpp); err != nil {
-				return fmt.Errorf("NDK version r19b detected, but >= r19c is required. Use the command `sdkmanager ndk-bundle` to install it.")
+				return fmt.Errorf("NDK version r19b detected, but >= r19c is required. Use the command `sdkmanager ndk-bundle` to install it")
 			}
 		}
 		archDir := filepath.Join(tmpDir, "jni", arch.jniArch)

ui/app/egl.go

@@ -89,7 +89,7 @@ func (c *context) Present() error {
 		c.srgbFBO.Blit()
 	}
 	if !eglSwapBuffers(c.eglCtx.disp, c.eglSurf) {
-		return fmt.Errorf("eglSwapBuffers failed (%x%x)", eglGetError())
+		return fmt.Errorf("eglSwapBuffers failed (%x)", eglGetError())
 	}
 	if c.srgbFBO != nil {
 		c.srgbFBO.AfterPresent()

ui/app/internal/gpu/caches.go

@@ -81,7 +81,7 @@ func (r *opCache) get(key ops.Key) (resource, bool) {
 
 func (r *opCache) put(key ops.Key, val resource) {
 	if _, exists := r.newRes[key]; exists {
-		panic(fmt.Errorf("key exists, %p", key))
+		panic(fmt.Errorf("key exists, %#v", key))
 	}
 	r.res[key] = val
 	r.newRes[key] = val

ui/app/internal/gpu/gpu.go

@@ -349,7 +349,7 @@ func (g *GPU) renderLoop(glctx gl.Context) error {
 					zt, st, covt, cleant := zopsTimer.Elapsed, stencilTimer.Elapsed, coverTimer.Elapsed, cleanupTimer.Elapsed
 					ft := zt + st + covt + cleant
 					q := 100 * time.Microsecond
-					zt, st, covt, cleant = zt.Round(q), st.Round(q), covt.Round(q), cleant.Round(q)
+					zt, st, covt = zt.Round(q), st.Round(q), covt.Round(q)
 					ft = ft.Round(q)
 					res.summary = fmt.Sprintf("f:%7s zt:%7s st:%7s cov:%7s", ft, zt, st, covt)
 				}

ui/app/window.go

@@ -361,4 +361,4 @@ func WithHeight(h ui.Value) WindowOption {
 	}
 }
 
-func (_ driverEvent) ImplementsEvent() {}
+func (driverEvent) ImplementsEvent() {}

ui/internal/ops/reader.go

@@ -33,7 +33,6 @@ type Key struct {
 
 // Shadow of ui.MacroOp.
 type macroOp struct {
-	recording bool
 	ops       *ui.Ops
 	version   int
 	pc        pc