[kawacukennedy]

What?

Use STARTTLS for all non-993 IMAP ports, matching the SMTP path logic.

Why?

Fixes #1688

Matcha previously only used STARTTLS on ports 1143 and 143, falling back to implicit TLS on every other port. This broke local IMAP bridges (e.g. Proton Mail Bridge) that serve IMAP on non-standard ports with STARTTLS. Port 993 uses implicit TLS; all other ports now correctly use STARTTLS.

[floatpanebot]

Benchmark report — no significant change

Metrics worse: 0 · better: 0 (threshold: ±3%).

benchstat output

goos: linux
goarch: amd64
pkg: github.com/floatpane/matcha/backend
cpu: AMD EPYC 7763 64-Core Processor                
                           │    old.txt    │               new.txt               │
                           │    sec/op     │    sec/op      vs base              │
ParseSearchQuery_Simple-4    2.787µ ± 880%   3.231µ ± 181%       ~ (p=0.937 n=6)
ParseSearchQuery_Complex-4   7.572µ ± 140%   7.467µ ± 105%       ~ (p=0.699 n=6)
TokenizeSearchQuery-4        5.559µ ± 135%   4.505µ ± 140%       ~ (p=0.485 n=6)
geomean                      4.895µ          4.772µ         -2.51%

                           │  old.txt   │              new.txt               │
                           │    B/op    │    B/op     vs base                │
ParseSearchQuery_Simple-4    26.00 ± 0%   26.00 ± 0%       ~ (p=1.000 n=6) ¹
ParseSearchQuery_Complex-4   762.0 ± 0%   762.0 ± 0%       ~ (p=1.000 n=6) ¹
TokenizeSearchQuery-4        176.0 ± 0%   176.0 ± 0%       ~ (p=1.000 n=6) ¹
geomean                      151.6        151.6       +0.00%
¹ all samples are equal

                           │  old.txt   │              new.txt               │
                           │ allocs/op  │ allocs/op   vs base                │
ParseSearchQuery_Simple-4    2.000 ± 0%   2.000 ± 0%       ~ (p=1.000 n=6) ¹
ParseSearchQuery_Complex-4   23.00 ± 0%   23.00 ± 0%       ~ (p=1.000 n=6) ¹
TokenizeSearchQuery-4        9.000 ± 0%   9.000 ± 0%       ~ (p=1.000 n=6) ¹
geomean                      7.453        7.453       +0.00%
¹ all samples are equal

pkg: github.com/floatpane/matcha/tui
                    │   old.txt    │               new.txt               │
                    │    sec/op    │    sec/op      vs base              │
LogPanelView-4        159.6µ ± 17%    178.0µ ± 10%       ~ (p=0.065 n=6)
SearchOverlayView-4   161.5µ ±  5%    176.5µ ±  9%  +9.30% (p=0.002 n=6)
InboxConstruction-4   945.1µ ± 23%   1031.0µ ±  9%       ~ (p=0.093 n=6)
geomean               289.9µ          318.8µ        +9.97%

                    │    old.txt    │                new.txt                │
                    │     B/op      │      B/op       vs base               │
LogPanelView-4        44.67Ki ± 51%   21.80Ki ± 105%        ~ (p=0.459 n=6)
SearchOverlayView-4   56.15Ki ± 41%   44.67Ki ±  26%        ~ (p=0.504 n=6)
InboxConstruction-4   874.5Ki ±  0%   874.4Ki ±   0%        ~ (p=0.513 n=6)
geomean               129.9Ki         94.78Ki         -27.05%

                    │   old.txt   │              new.txt              │
                    │  allocs/op  │  allocs/op   vs base              │
LogPanelView-4         714.0 ± 0%    713.0 ± 0%       ~ (p=0.567 n=6)
SearchOverlayView-4    926.0 ± 0%    925.0 ± 0%       ~ (p=0.545 n=6)
InboxConstruction-4   3.484k ± 0%   3.482k ± 0%       ~ (p=0.416 n=6)
geomean               1.321k        1.319k       -0.10%

_{auto-generated by benchmarks.yml}

[floatpanebot]

This has had no activity for 45 days. It will be closed in 21 days unless updated. Comment or remove the stale label to keep it open.

[kawacukennedy]

Hi @andrinoff — this PR is still open and all CI checks are green; just keeping it off the stale queue. Happy to rebase/adjust if anything needs updating. Thanks!

[floatpanebot]

This has had no activity for 45 days. It will be closed in 21 days unless updated. Comment or remove the stale label to keep it open.

[kawacukennedy]

Rebased onto the new v1.0.0 master to clear the conflict. The change re-applies cleanly to the restructured fetcher/fetcher.go:

• Port 993 keeps implicit TLS.
• All other ports try DialStartTLS first (supports local bridges like Proton Mail Bridge) and fall back to implicit TLS if STARTTLS is refused (e.g. GreenMail on 3993).
• Updated the in-tree test server to actually exercise the STARTTLS handshake.

go build ./..., go vet, make test and golangci-lint are green locally, and the PR is now MERGEABLE.

[kawacukennedy]

CI note: the only failing check here is govulncheck, and it's a pre-existing issue on master (not caused by this PR). A new Go stdlib advisory, GO-2026-6809, was published after go 1.26.9 and is fixed in go 1.26.10; the repo still pins 1.26.9.

I've opened #1749 to bump the toolchain (also reachable via fetch → pkcs7 → x509). Once that lands, this PR's govulncheck will go green. Everything else in the matrix is passing.