When a custom/proxy provider serves models whose IDs share the same base
name across vendor prefixes (e.g. vendor_a/deepseek/deepseek-v4-pro vs
vendor_b/deepseek/deepseek-v4-pro), several normalization functions use
split('/').pop() (or split('/')[-1]) which discards all segments except
the last. This causes three user-facing symptoms: (1) clicking one
model selects a different colliding model, (2) configured-model badges
attach to the wrong dropdown entry, and (3) the model-chip label in the
composer bar is truncated to just the base model name.
Root cause: all three callers take only the last slash-segment instead
of stripping only the first (provider) segment and preserving the
remaining vendor hierarchy.
Fix 1 — _findModelInDropdown (static/ui.js): Move the exact string match
before the provider-aware normalized match. Previously, when all models
share the same provider ID (common with LLM proxy setups), the normalized
match returned whichever colliding option appeared first in DOM order,
even though an exact match existed.
Fix 2 — _normalizeConfiguredModelKey (static/ui.js) and _norm_model_id
(api/config.py): Replace split('/').pop() / split('/')[-1] with a first-
segment-only strip (regex on frontend, split('/',1) on backend), matching
the strategy already used by _findModelInDropdown's norm lambda. This
prevents multi-slash IDs from colliding in badge assignment and the
configured-entry dedup set. Additionally, strip colon-qualified provider
prefixes (e.g. custom:name/) before the slash strip so badge-key variants
like 'custom:llm-proxy/opencode_go/model' merge correctly with the bare
'opencode_go/model' in the configured section dedup.
Fix 3 — getModelLabel (static/ui.js) and _get_label_for_model
(api/config.py): Same split('/').pop() to first-segment-strip change so
the composer-bar model chip and backend label preserve vendor context
(e.g. shows 'opencode_go/deepseek-v4-pro' instead of 'deepseek-v4-pro').
Verification: 9 new regression tests (test_issue3360) covering exact-
match priority, multi-slash normalization, and backend/frontend parity.
Updated 1 existing test (test_norm_model_id_trailing_empty_guard) that
asserted the old split('/').pop() pattern. All 25 related tests pass.
AI Usage: Gemini (gemini-2.5-pro), via Antigravity IDE, pair-programmed.
(cherry picked from commit a454fecd2b3a83f7da34473c883be069171aeac9)
d06776a4c8