From 0cd1529008f6cdb4ea741bb0347a9ff02570715c Mon Sep 17 00:00:00 2001
From: Classic298 <27028174+Classic298@users.noreply.github.com>
Date: Fri, 15 May 2026 02:29:25 +0200
Subject: [PATCH] fix: default optional env vars used with bash `,,` in
 start.sh (#24683)
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start.sh runs with `set -euo pipefail`, but three call sites added in
070ab2650 (refac: reorganize scripts and ci workflows) reference
optional env vars via bash's `,,` lowercase expansion without any
default. Containers that don't set these vars — the default for every
deployment that isn't explicitly opting into Playwright / bundled
Ollama / CUDA — crash on startup with:

    start.sh: line 15: WEB_LOADER_ENGINE: unbound variable

(and the same for USE_OLLAMA_DOCKER, USE_CUDA_DOCKER once the first
were set in turn.) Reported in open-webui#24560 by urbenlegend.

The same refactor correctly defaulted every other optional env var
with `${VAR:-…}`. The three `,,` references slipped through because
bash can't combine `:-default` with `,,` in a single substitution —
`${VAR:-default,,}` makes the default literal `,,`, not what's wanted.

Fix: normalise the three vars in a one-line preamble with `${VAR:=}`,
which assigns an empty default if unset. The downstream `${VAR,,}`
expressions stay exactly as Tim wrote them, preserving the file's
visual style and matching the existing `${VAR:-…}` idiom for "this
variable is optional".
---
 backend/start.sh | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/backend/start.sh b/backend/start.sh
index fd283d31fd..9e65465095 100755
--- a/backend/start.sh
+++ b/backend/start.sh
@@ -7,6 +7,12 @@ set -euo pipefail
 # HuggingFace Space deployment, and launches the uvicorn server.
 # ---------------------------------------------------------------------------
 
+# Default optional env vars that we test below with bash's `,,` lowercase
+# expansion. The two can't be combined inline (`${VAR:-default,,}` makes
+# the default literal `,,`), so we normalise once up front and the simple
+# `${VAR,,}` form stays safe under `set -u` everywhere else.
+: "${WEB_LOADER_ENGINE:=}" "${USE_OLLAMA_DOCKER:=}" "${USE_CUDA_DOCKER:=}"
+
 SCRIPT_DIR=$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")" &>/dev/null && pwd)
 cd "$SCRIPT_DIR" || exit 1