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Fix: Remove inconsistent human readability warning from docker images #6754

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Merged
thaJeztah merged 1 commit into from
May 7, 2026
+12 −23
Merged

Fix: Remove inconsistent human readability warning from docker images #6754

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2 changes: 1 addition & 1 deletion cli/command/image/list.go
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Original file line number Diff line number Diff line change
Expand Up @@ -211,6 +211,6 @@ func printAmbiguousHint(stdErr io.Writer, matchName string) {
"save",
"tag":

_, _ = fmt.Fprintf(stdErr, "\nNo images found matching %q: did you mean \"docker image %[1]s\"?\n", matchName)
_, _ = fmt.Fprintf(stdErr, "No images found matching %q: did you mean \"docker image %[1]s\"?\n", matchName)
}
}
2 changes: 0 additions & 2 deletions cli/command/image/testdata/list-command-ambiguous.golden
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Original file line number Diff line number Diff line change
@@ -1,3 +1 @@
WARNING: This output is designed for human readability. For machine-readable output, please use --format.

No images found matching "ls": did you mean "docker image ls"?
20 changes: 0 additions & 20 deletions cli/command/image/tree.go
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Original file line number Diff line number Diff line change
Expand Up @@ -6,14 +6,12 @@ package image
import (
"context"
"fmt"
"os"
"slices"
"strings"

"github.com/containerd/platforms"
"github.com/docker/cli/cli/command"
"github.com/docker/cli/cli/command/formatter"
"github.com/docker/cli/cli/streams"
"github.com/docker/cli/internal/tui"
"github.com/docker/go-units"
imagetypes "github.com/moby/moby/api/types/image"
Expand Down Expand Up @@ -233,10 +231,6 @@ func getPossibleChips(view treeView) (chips []imageChip) {
}

func printImageTree(outs command.Streams, view treeView) {
if streamRedirected(outs.Out()) {
_, _ = fmt.Fprintln(outs.Err(), "WARNING: This output is designed for human readability. For machine-readable output, please use --format.")
}

out := tui.NewOutput(outs.Out())
isTerm := out.IsTerminal()

Expand Down Expand Up @@ -564,17 +558,3 @@ func widestFirstColumnValue(headers []imgColumn, images []topImage) int {
}
return width
}

func streamRedirected(s *streams.Out) bool {
fd := s.FD()
if os.Stdout.Fd() != fd {
return true
}

fi, err := os.Stdout.Stat()
if err != nil {
return true
}

return fi.Mode()&os.ModeCharDevice == 0
}
11 changes: 11 additions & 0 deletions cli/command/image/tree_test.go
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Expand Up @@ -157,6 +157,17 @@ func TestPrintImageTreeAnsiTty(t *testing.T) {
}
}

func TestPrintImageTreeNoWarningWhenRedirected(t *testing.T) {
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@ericpromislow ericpromislow May 7, 2026

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General software engineering guidelines: don't bother with negative unit tests because theoretically there's no end of tests you could write to verify something isn't happening.

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@thaJeztah thaJeztah May 7, 2026

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Yeah, I already had a branch prepared to removed it, because it's covered by the other tests already. We were in process of getting things ready for a v29.5.0 release candidate, and I wanted to make sure it didn't miss the boat.

Normally I would've amended the PR, but new restrictions now require paperwork and sign-offs from higher-up when doing so 😭 so I'll just fix it in a follow-up.

cli := test.NewFakeCli(nil)
cli.Out().SetIsTerminal(false)
cli.Err().SetIsTerminal(false)

printImageTree(cli, treeView{images: []topImage{}})

errOut := cli.ErrBuffer().String()
assert.Check(t, !strings.Contains(errOut, "WARNING: This output is designed for human readability"), "stderr should not contain warning when output is redirected, got: %s", errOut)
}

func TestPrintImageTreeGolden(t *testing.T) {
testCases := []struct {
name string
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