dbt panics with index out of range [-1] on valid SQL with nested CASE expressions

[odeta939]

Expected behavior

Model preview works just like in dbt cloud studio

Actual behavior

When using the Power User for dbt preview feature on a model containing a nested CASE inside another CASE, dbti panics with:

runtime error: index out of range [-1]
The panic occurs in extractValues at dbt.go:101, called from normalizeParams → InvokeDBT → showCommandHandler. The raw panic output is then returned to the caller, which fails to parse it as JSON:

SyntaxError: Unexpected token 'p', "panic: run"... is not valid JSON

Steps To Reproduce

1. Create a dbt model with a nested CASE expression, e.g.:

CASE
    WHEN MONTH(some_date) < (
        CASE
            WHEN some_col = 'JAN' THEN 1
            WHEN some_col = 'FEB' THEN 2
            ...
        END
    )
    THEN ...
    ELSE ...
END

2. Compile and run the model successfully in dbt
3. Attempt to preview the model using Power User for dbt

Log output/Screenshots

goroutine 1 [running]: dbt-labs/dbti/cmd/util.extractValues({0x16d2d6aa9?, 0x8?}) /home/runner/work/dbti/dbti/cmd/util/dbt.go:101 +0x214 dbt-labs/dbti/cmd/util.normalizeParams({0x140001ba360?, 0x102c8b204?, 0x102fcef5e?}) /home/runner/work/dbti/dbti/cmd/util/dbt.go:76 +0x90 dbt-labs/dbti/cmd/util.InvokeDBT({0x1031d16a0, 0x1400025a540}, {0x1031cc148, 0x1400011b1a0}, {0x140001ba360, 0x9, 0x9}, 0x0, 0x1, 0x0) /home/runner/work/dbti/dbti/cmd/util/dbt.go:24 +0x84 dbt-labs/dbti/cmd.Show.showCommandHandler.func1(0x140001f3208, {0x140001a2300?, 0x4?, 0x102fceeee?}) /home/runner/work/dbti/dbti/cmd/show.go:189 +0xd94 github.com/spf13/cobra.(*Command).execute(0x140001f3208, {0x140001a2240, 0xc, 0xc}) /home/runner/go/pkg/mod/github.com/spf13/cobra@v1.7.0/command.go:944 +0x63c github.com/spf13/cobra.(*Command).ExecuteC(0x140001be308) /home/runner/go/pkg/mod/github.com/spf13/cobra@v1.7.0/command.go:1068 +0x320 github.com/spf13/cobra.(*Command).Execute(0x1031d1768?) /home/runner/go/pkg/mod/github.com/spf13/cobra@v1.7.0/command.go:992 +0x1c main.main() /home/runner/work/dbti/dbti/main.go:21 +0xf0 : SyntaxError: Unexpected token 'p', "panic: run"... is not valid JSON

Operating System

macOS 26.3.1

dbt version

dbt Cloud CLI - 0.40.15

dbt Adapter

dbt-snowflake

dbt Power User version

0.60.4

Are you willing to submit PR?

• Yes I am willing to submit a PR!

[mdesmet]

I'm assuming you are using Fusion in dbt Cloud? we are working on supporting that.