Enable errorlint for error comparisons and type assertions

.golangci.yaml

@@ -35,7 +35,13 @@ linters:
     - reassign
     - modernize
     - makezero
+    - errorlint
   settings:
+    errorlint:
+      # Switching %v to %w changes which errors callers can match with
+      # errors.Is/As (e.g. fs.ErrNotExist, context.Canceled), so it needs
+      # per-site review rather than a bulk fix.
+      errorf: false
     modernize:
       # omitzero changes JSON wire format for nested structs (unlike omitempty),
       # so each site needs per-site review rather than a bulk rewrite.

acceptance/acceptance_test.go

@@ -1648,7 +1648,7 @@ func formatOutput(w io.Writer, err error) {
 	if err == nil {
 		return
 	}
-	if exiterr, ok := err.(*exec.ExitError); ok {
+	if exiterr, ok := errors.AsType[*exec.ExitError](err); ok {
 		exitCode := exiterr.ExitCode()
 		fmt.Fprintf(w, "\nExit code: %d\n", exitCode)
 	} else {
@@ -1859,7 +1859,7 @@ func runWithLog(t *testing.T, cmd *exec.Cmd, out *os.File, tail bool, timeout ti
 				require.NoError(t, err)
 			}
 		}
-		if err == io.EOF {
+		if errors.Is(err, io.EOF) {
 			break
 		}
 		require.NoError(t, err)

acceptance/internal/prepare_server.go

@@ -3,6 +3,7 @@ package internal
 import (
 	"bytes"
 	"encoding/json"
+	"errors"
 	"fmt"
 	"io"
 	"mime"
@@ -376,7 +377,7 @@ func normalizeMultipartBody(req *testserver.Request) (any, bool) {
 	parts := map[string]any{}
 	for {
 		part, err := mr.NextPart()
-		if err == io.EOF {
+		if errors.Is(err, io.EOF) {
 			break
 		}
 		if err != nil {

bundle/artifacts/tarball_test.go

@@ -4,6 +4,7 @@ import (
 	"archive/tar"
 	"bytes"
 	"compress/gzip"
+	"errors"
 	"io"
 	"os"
 	"os/exec"
@@ -26,7 +27,7 @@ func tarEntries(t *testing.T, b []byte) map[string]string {
 	out := map[string]string{}
 	for {
 		hdr, err := tr.Next()
-		if err == io.EOF {
+		if errors.Is(err, io.EOF) {
 			break
 		}
 		require.NoError(t, err)

bundle/config/mutator/python/python_mutator.go

@@ -293,7 +293,7 @@ func (m *pythonMutator) Apply(ctx context.Context, b *bundle.Bundle) diag.Diagno
 	b.Metrics.PythonUpdatedResourcesCount += int64(result.UpdatedResources.Size())
 	b.Metrics.PythonAddedResourcesCount += int64(result.AddedResources.Size())
 
-	if err == mutateDiagsHasError {
+	if errors.Is(err, mutateDiagsHasError) {
 		if !mutateDiags.HasError() {
 			panic("mutateDiags has no error, but error is expected")
 		}

cmd/air/logstream_test.go

@@ -62,10 +62,10 @@ func TestClassifyLogError(t *testing.T) {
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
 			got := classifyLogError(tt.err)
-			switch tt.want {
-			case errBricklensFeatureDisabled:
+			switch {
+			case errors.Is(tt.want, errBricklensFeatureDisabled):
 				assert.ErrorIs(t, got, errBricklensFeatureDisabled)
-			case nil:
+			case tt.want == nil:
 				assert.NoError(t, got)
 			default:
 				assert.ErrorIs(t, got, tt.want)

cmd/auth/env.go

@@ -79,7 +79,7 @@ func loadFromDatabricksCfg(ctx context.Context, cfg *config.Config) error {
 		return err
 	}
 	profile, err := resolveSection(cfg, iniFile)
-	if err == ErrNoMatchingProfiles {
+	if errors.Is(err, ErrNoMatchingProfiles) {
 		// it's also fine for Azure CLI or Databricks CLI, which
 		// are resolved by unified auth handling in the Go SDK.
 		return nil

cmd/bundle/validate.go

@@ -2,6 +2,7 @@ package bundle
 
 import (
 	"encoding/json"
+	"errors"
 	"fmt"
 
 	"github.com/databricks/cli/bundle"
@@ -67,7 +68,7 @@ Please run this command before deploying to ensure configuration quality.`,
 		})
 		ctx := cmd.Context()
 
-		if err != nil && err != root.ErrAlreadyPrinted {
+		if err != nil && !errors.Is(err, root.ErrAlreadyPrinted) {
 			logdiag.LogError(ctx, err)
 			err = root.ErrAlreadyPrinted
 		}

experimental/ssh/internal/client/agentshim.go

@@ -378,7 +378,7 @@ func probeModelServices(ctx context.Context, apiClient *client.DatabricksClient)
 	it := catalog.NewAiGateway(apiClient).ListModelServices(ctx, catalog.ListModelServicesRequest{PageSize: modelServiceProbePageSize})
 	_, err := it.Next(ctx)
 	if err != nil {
-		if err == listing.ErrNoMoreItems {
+		if errors.Is(err, listing.ErrNoMoreItems) {
 			// endpoint is reachable but there are no results
 			return gatewayProbe{reachable: true}
 		}

libs/appproxy/appproxy.go

@@ -2,6 +2,7 @@ package appproxy
 
 import (
 	"context"
+	"errors"
 	"io"
 	"net"
 	"net/http"
@@ -113,7 +114,7 @@ func (p *Proxy) handleWebSocket(w http.ResponseWriter, r *http.Request) {
 	err = <-errc
 	if err != nil {
 		// If the error is not EOF, then there was a problem
-		if err != io.EOF {
+		if !errors.Is(err, io.EOF) {
 			// Log the error and perform cleanup
 			log.Warnf(r.Context(), "error copying messages: %v", err)
 			middlewareConn.Close()

libs/databrickscfg/loader.go

@@ -188,7 +188,7 @@ func (l profileFromHostLoader) Configure(cfg *config.Config) error {
 		// Check if this section matches the normalized host
 		return normalizeHost(key.Value()) == host
 	})
-	if err == errNoMatchingProfiles {
+	if errors.Is(err, errNoMatchingProfiles) {
 		return nil
 	}
 
@@ -197,7 +197,7 @@ func (l profileFromHostLoader) Configure(cfg *config.Config) error {
 	if names, ok := AsMultipleProfiles(err); ok && cfg.WorkspaceID != "" {
 		originalErr := err
 		match, err = l.disambiguateByWorkspaceID(ctx, configFile, host, cfg.WorkspaceID, names)
-		if err == errNoMatchingProfiles {
+		if errors.Is(err, errNoMatchingProfiles) {
 			// workspace_id didn't match any of the host-matching profiles.
 			// Fall back to the original ambiguity error.
 			log.Debugf(ctx, "workspace_id=%s did not match any profiles for host %s: %v", cfg.WorkspaceID, host, names)

libs/databrickscfg/ops.go

@@ -353,7 +353,7 @@ func matchOrCreateSection(ctx context.Context, configFile *config.File, cfg *con
 		// Check if this section matches the normalized host
 		return normalizeHost(host) == normalizeHost(cfg.Host)
 	})
-	if err == errNoMatchingProfiles {
+	if errors.Is(err, errNoMatchingProfiles) {
 		section, err = configFile.NewSection(cfg.Profile)
 		if err != nil {
 			return nil, fmt.Errorf("cannot create new profile: %w", err)

libs/dyn/jsonloader/json.go

@@ -24,7 +24,7 @@ func LoadJSON(data []byte, source string) (dyn.Value, error) {
 	// Start decoding from the top-level value
 	value, err := decodeValue(decoder, &offset)
 	if err != nil {
-		if err == io.EOF {
+		if errors.Is(err, io.EOF) {
 			err = errors.New("unexpected end of JSON input")
 		}
 		// Get the current offset for error reporting

libs/dyn/walk.go

@@ -25,7 +25,7 @@ func Walk(v Value, fn func(p Path, v Value) (Value, error)) (Value, error) {
 func walk(v Value, p Path, fn func(p Path, v Value) (Value, error)) (Value, error) {
 	v, err := fn(p, v)
 	if err != nil {
-		if err == ErrSkip {
+		if errors.Is(err, ErrSkip) {
 			return v, nil
 		}
 		return InvalidValue, err
@@ -39,7 +39,7 @@ func walk(v Value, p Path, fn func(p Path, v Value) (Value, error)) (Value, erro
 			pk := pair.Key
 			pv := pair.Value
 			nv, err := walk(pv, append(p, Key(pk.MustString())), fn)
-			if err == ErrDrop {
+			if errors.Is(err, ErrDrop) {
 				continue
 			}
 			if err != nil {
@@ -53,7 +53,7 @@ func walk(v Value, p Path, fn func(p Path, v Value) (Value, error)) (Value, erro
 		out := make([]Value, 0, len(s))
 		for i := range s {
 			nv, err := walk(s[i], append(p, Index(i)), fn)
-			if err == ErrDrop {
+			if errors.Is(err, ErrDrop) {
 				continue
 			}
 			if err != nil {

libs/dyn/walk_read_only.go

@@ -1,5 +1,7 @@
 package dyn
 
+import "errors"
+
 // WalkReadOnly walks the configuration tree in readonly mode and calls the given function on each node.
 // The callback may return ErrSkip to skip traversal of a subtree.
 // If the callback returns another error, the walk is aborted, and the error is returned.
@@ -12,7 +14,7 @@ func WalkReadOnly(v Value, fn func(p Path, v Value) error) error {
 // such that it can be passed to the callback function.
 func walkReadOnly(v Value, p Path, fn func(p Path, v Value) error) error {
 	if err := fn(p, v); err != nil {
-		if err == ErrSkip {
+		if errors.Is(err, ErrSkip) {
 			return nil
 		}
 		return err

libs/dyn/yamlloader/yaml.go

@@ -1,6 +1,7 @@
 package yamlloader
 
 import (
+	"errors"
 	"io"
 
 	"github.com/databricks/cli/libs/dyn"
@@ -12,7 +13,7 @@ func LoadYAML(path string, r io.Reader) (dyn.Value, error) {
 	dec := yaml.NewDecoder(r)
 	err := dec.Decode(&node)
 	if err != nil {
-		if err == io.EOF {
+		if errors.Is(err, io.EOF) {
 			return dyn.NilValue, nil
 		}
 		return dyn.InvalidValue, err

libs/exec/exec.go

@@ -3,6 +3,7 @@ package exec
 import (
 	"bytes"
 	"context"
+	"errors"
 	"fmt"
 	"io"
 	"os"
@@ -190,7 +191,7 @@ func (e *Executor) ExecAndCapture(ctx context.Context, command string) (*ExecOut
 	err = cmd.Wait()
 	exitCode := 0
 	if err != nil {
-		if exitErr, ok := err.(*osexec.ExitError); ok {
+		if exitErr, ok := errors.AsType[*osexec.ExitError](err); ok {
 			exitCode = exitErr.ExitCode()
 		} else {
 			return nil, err

libs/filer/files_client_test.go

@@ -212,7 +212,7 @@ func TestMapUploadError(t *testing.T) {
 
 	// Other errors pass through unchanged.
 	other := errors.New("boom")
-	if got := mapUploadError(other, p); got != other {
+	if got := mapUploadError(other, p); got != other { //nolint:errorlint // must be the same error, not a wrapper
 		t.Errorf("mapUploadError(other) = %v, want it unchanged", got)
 	}
 }

libs/genie/agentstream/renderer.go

@@ -37,7 +37,7 @@ func RenderDebug(r io.Reader, w io.Writer) error {
 	reader := NewSSEReader(r)
 	for {
 		ev, err := reader.Next()
-		if err == io.EOF {
+		if errors.Is(err, io.EOF) {
 			return nil
 		}
 		if err != nil {
@@ -92,7 +92,7 @@ func RenderText(ctx context.Context, r io.Reader, stdout, stderr io.Writer, adap
 
 	for {
 		ev, err := reader.Next()
-		if err == io.EOF {
+		if errors.Is(err, io.EOF) {
 			break
 		}
 		if err != nil {
@@ -198,7 +198,7 @@ func RenderJSON(r io.Reader, stdout, stderr io.Writer, adapt AdapterFunc) (strin
 loop:
 	for {
 		ev, err := reader.Next()
-		if err == io.EOF {
+		if errors.Is(err, io.EOF) {
 			break
 		}
 		if err != nil {

libs/git/reference.go

@@ -86,7 +86,7 @@ func (ref *Reference) ResolvePath() (string, error) {
 // `ref: refs/heads/my-branch` returns `my-branch`
 func (ref *Reference) CurrentBranch() (string, error) {
 	branchRefPath, err := ref.ResolvePath()
-	if err == ErrNotAReferencePointer {
+	if errors.Is(err, ErrNotAReferencePointer) {
 		return "", ErrNotABranch
 	}
 	if err != nil {

libs/tarpack/tarpack_test.go

@@ -3,6 +3,7 @@ package tarpack
 import (
 	"archive/tar"
 	"bytes"
+	"errors"
 	"io"
 	"os"
 	"path/filepath"
@@ -26,7 +27,7 @@ func readTar(t *testing.T, b []byte) map[string]readEntry {
 	out := map[string]readEntry{}
 	for {
 		hdr, err := tr.Next()
-		if err == io.EOF {
+		if errors.Is(err, io.EOF) {
 			break
 		}
 		require.NoError(t, err)

libs/testserver/handlers.go

@@ -4,6 +4,7 @@ import (
 	"bytes"
 	"encoding/base64"
 	"encoding/json"
+	"errors"
 	"fmt"
 	"io"
 	"mime"
@@ -141,7 +142,7 @@ func ParseImportForm(req Request) (ImportForm, error) {
 	mr := multipart.NewReader(bytes.NewReader(req.Body), params["boundary"])
 	for {
 		part, err := mr.NextPart()
-		if err == io.EOF {
+		if errors.Is(err, io.EOF) {
 			return form, nil
 		}
 		if err != nil {
@@ -907,7 +908,7 @@ func AddDefaultHandlers(server *Server) {
 		var bundleID, snapshotID string
 		for {
 			p, err := mr.NextPart()
-			if err == io.EOF {
+			if errors.Is(err, io.EOF) {
 				break
 			}
 			if err != nil {

tools/testrunner/main.go

@@ -18,6 +18,7 @@ import (
 	"bufio"
 	"context"
 	"encoding/json"
+	"errors"
 	"fmt"
 	"io"
 	"net/http"
@@ -45,7 +46,7 @@ func getExitCode(err error) (int, error) {
 	if err == nil {
 		return 0, nil
 	}
-	if exitError, ok := err.(*exec.ExitError); ok {
+	if exitError, ok := errors.AsType[*exec.ExitError](err); ok {
 		if status, ok := exitError.Sys().(syscall.WaitStatus); ok {
 			return status.ExitStatus(), nil
 		}