[T4rk1n]

Third release candidate for 4.5.0.

• dash/version.py -> 4.5.0rc2
• npm sub-packages bumped to the next patch, since rc1 already published their x.5.1 versions to npm: dash-core-components 4.5.2, dash-html-components 4.5.2, dash-table 7.5.2, dash-renderer 3.5.2 (package.json + lockfile version fields + _dash_renderer.py __version__/external_url). Renderer rebuilt.
• CHANGELOG: added the missing entry for fix(renderer): clear paths for null children #4052.

Since rc1 (see CHANGELOG [Unreleased] for the full list)

Changed

• plotly-cloud moved back to the optional dash[cloud] extra (Move plotly-cloud back to the optional cloud extra #4073)

Removed

• Python version checks for versions before 3.9 (Remove unnecessary python version checks. #4039)

Fixed

• Security fixes reported against rc1 (Fix security findings reported against 4.5.0rc1 #4075): before_request hooks on all FastAPI routes and WebSocket handshakes, background callback cache keys, javascript: URLs in dcc.Location/html.Area/html.Base href, pages path_template matching on newlines, per-user MCP cache (configure_mcp_server(cache_by=..., cache_maxsize=...))
• Callbacks of removed components still firing after children is set to None (fix(renderer): clear paths for null children #4052)

Plus dependency and CI updates (#4072, #4079).

Before final 4.5.0

• Rename CHANGELOG [Unreleased] -> [4.5.0] - <date>
• Drop the rc2 from dash/version.py

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[github-actions]

Dash performance benchmarks

⚠️ regressions to review

	scenario	metric	p90 (ms)	median	growth	baseline p90	note
⚠️	full_children_replace	replace_ms	6239.9	2179.6	20.44x	4697.1	p90 6239.9ms > warn 6000ms
✅	callback_chain	chain_ms	507.0	476.1	1.0x	499.1
✅	callback_chain	graph_ms	2.4	2.4	1.0x	2.4
✅	callback_fanout	fanout_ms	88.9	83.5	0.88x	92.5
✅	deep_nesting	render_ms	72.2	65.1	1.28x	56.8
✅	initial_render_large	render_ms	816.4	650.6	1.31x	694.4
✅	initial_render_small	render_ms	107.5	102.1	1.08x	104.0
✅	patch_append_nested	append_ms	180.8	121.9	2.25x	192.3
✅	patch_append_toplevel	append_ms	156.1	115.9	2.28x	140.2
✅	patch_scalar_update_large	update_ms	169.0	157.9	0.88x	202.9
✅	wildcard_all_resolve	wildcard_ms	308.7	293.8	0.95x	313.6
✅	wildcard_all_resolve	graph_ms	1.5	1.5	1.0x	1.3

growth = late-third / early-third per-op time; ~1 is flat, a large value means the per-op cost scales with accumulated state.

machine scale vs baseline: 1.06x - divided out of the baseline ratios so they compare like for like (the absolute warn/fail ceilings are left un-scaled); calibrated on initial_render_small.