Status after dependency cleanup: this branch contains only the loader selection and TLS tests. The weak hook is in #5633 and is required for the runtime test. The new head has not completed CI. Earlier CI results apply to the previous combined branch. The overlapping loader work in #5645 is under discussion with its owner.

loader: use the real crypto/tls on hosted linux and darwin

Depends on upstream-pr/weak-strong-from-weak.

What this does

TinyGo replaces crypto/tls with a stub whose handshake does nothing, so a
program that dials https:// gets a plaintext connection behind the TLS API.
That stub is correct for a target with no OS below it, which has neither the
code size for a full TLS implementation nor usually a socket to speak it over.
Hosted linux and macOS have both, and there the crypto/tls of the Go standard
library compiles and runs.

The override becomes conditional. Without an entry in the map, crypto/tls
falls under the "crypto/" merge, which links the package of the standard
library into the synthetic GOROOT. GOOS alone cannot decide this, because a
baremetal target reports GOOS=linux, so the build tags decide as well. The
goroot cache key is a hash of the merge links, so the two variants get separate
cache entries.

Evidence

testdata/hostcryptotls.go makes an ECDSA key and a self-signed certificate at
run time, then does a TLS handshake over net.Pipe. It needs no network and no
netdev. TestHostCryptoTLS in main_test.go runs it on the host, and skips
where the host is not linux or darwin, in the same way as
TestTimerStopResetRace.

Measured on macOS 26.6 arm64.

The first row shows what the stub does. It reports a completed handshake and a
version of zero, and it does not verify anything. The second row shows a real
TLS 1.3 handshake, data through the connection, and a client with an empty root
pool refusing the certificate.

loader/goroot_test.go covers the decision itself, with the baremetal case that
reports GOOS=linux.

A downstream product ships binaries built with these changes in a production
release. dispat v1.4.0 is published and is not a prerelease. It carries
dispat-tiny-linux-amd64 and dispat-tiny-linux-arm64, built by the fork
release v0.42.0-net.4 from sha256-pinned tarballs and smoke-executed under
binfmt before upload, beside six binaries from the gc toolchain.
https://github.com/yohimik/dispat/releases/tag/services%2Fdispat%2Fv1.4.0

The acceptance record of that repository is committed at
packages/docs/docs/internals/tinygo.md. It reports the net.2 to net.4
acceptance history, an integration suite of 694 rows that passes with 0 failures
and 1 documented skip on darwin, and a size table of 0.58x to 0.63x against the
gc equivalents with TinyGo -opt=z -no-debug against go build -trimpath -ldflags "-s -w". Those figures come from that document. They are not a
measurement of this branch.

The self-update path of that program runs over real TLS against a live host, and
its suite has negative rows as well. An unknown CA is refused, and a plaintext
server on a TLS port is refused.

Scope and known gaps

• Windows keeps the stub. So do wasm, wasip1, wasip2, wasm_unknown,
  nintendoswitch and every baremetal target. Their behaviour does not change.
• Only a program that imports crypto/tls sees a size change, and such a
  program did not work before.
• crypto/x509 on darwin uses the platform verifier, and
  crypto/x509/internal/macos in TinyGo is a stub, so a nil RootCAs fails on
  darwin. net/http in tinygo-org/net handles this by giving the client a root
  pool. A caller that dials tls.Dial directly on darwin has to supply
  RootCAs. See the tinygo-org/net PR "net/http: give the HTTPS client trust
  roots on darwin".
• http.Client.Timeout is inert in the tinygo-org/net client. It is not
  addressed here.
• crypto/tls API mismatch: missing tls.X509KeyPair and ClientAuth constants, LoadX509KeyPair stubbed #5204 lists crypto/tls API gaps such as tls.X509KeyPair. This change makes
  the real package available on hosted targets, so those gaps disappear there,
  but the stub keeps them on every other target.

Related

• Does tinygo not support TLS features? #4269, "Does tinygo not support TLS features?"
• build error: net/smtp module reports undefined: tls.Conn #4624, "build error: net/smtp module reports undefined: tls.Conn"
• crypto/tls API mismatch: missing tls.X509KeyPair and ClientAuth constants, LoadX509KeyPair stubbed #5204, "crypto/tls API mismatch: missing tls.X509KeyPair and ClientAuth
  constants, LoadX509KeyPair stubbed"
• Missing stdlib symbols on Linux native: net/http.Server.ListenAndServeTLS and net.* APIs #5205, "Missing stdlib symbols on Linux native"

This is a smaller change than the netdev reworks in #4187, #4273 and #4498. It
does not replace the net package or add a netpoller. It only stops the
substitution of the TLS stub where the standard library package works.

Enables

A command line program that needs an HTTPS client path. Self-update, an API
client, a webhook sender. Client side only. There is no server claim here beyond
what the tests show.

Related pull requests

Each open PR in this series has a separate change. A dependency is not a copied commit.

• sync: hand the RWMutex over instead of a re-test of the reader count #5630 fixes RWMutex handover.
• runtime: deliver os/signal notifications under the threads scheduler #5631 is closed in favor of runtime: deliver signals under the threads scheduler when blocked on I/O #5530, owned by @0pcom. The fork still uses the tested runtime: deliver os/signal notifications under the threads scheduler #5631 implementation until a replacement is checked.
• compiler,runtime: call fcntl through a C wrapper on darwin #5632 is closed in favor of compiler: implement go:cgo_import_dynamic and lower Darwin cgo import trampolines (#5604) #5612, owned by @neomantra. compiler: implement go:cgo_import_dynamic and lower Darwin cgo import trampolines (#5604) #5612 covers both stdlib and x/sys Darwin trampolines.
• runtime: implement weak.runtime_makeStrongFromWeak #5633 provides the weak-pointer runtime hook.
• os: start processes with posix_spawn #5634 provides process spawning and process state. Darwin also needs compiler: implement go:cgo_import_dynamic and lower Darwin cgo import trampolines (#5604) #5612 and builder: declare Darwin socket and process symbols #5636. Concurrent use needs sync: hand the RWMutex over instead of a re-test of the reader count #5630.
• loader: use the real crypto/tls on hosted linux and darwin #5635 selects software TLS on hosted Linux and Darwin. It needs runtime: implement weak.runtime_makeStrongFromWeak #5633. The overlapping crypto/tls: use Go's software TLS on the host target #5645 is under discussion with @0pcom.
• builder: declare Darwin socket and process symbols #5636 provides the Darwin socket and process link symbols. It does not include process or TLS implementation changes.

In tinygo-org/net

• net/http: follow redirects in the client again net#72 restores HTTP redirects. It shares http/client.go with the timeout work in http: port Go net/http timeout handling net#67, so the two changes need integration review.
• net: report a name that does not exist as a not-found lookup error net#73 preserves DNS not-found errors.
• net: extend the host netdev to darwin net#74 adds Darwin host netdev support. It shares the host netdev with net: non-blocking host netdev I/O with an epoll poller net#77. Linux epoll and Darwin support must remain separate.
• net/http: give the HTTPS client trust roots on darwin net#75 supplies Darwin trust roots to the HTTP client.
• net: non-blocking host netdev I/O with an epoll poller net#77 owns Linux cancellation and deadline work, net: report the kernel-assigned port after listening on port 0 net#80 owns port-zero reporting, and net/http: add ListenAndServeTLS / ServeTLS (software TLS) net#79 owns HTTP server TLS. These are separate contributors' changes, not completed parts of this series.
• net: API-compat fills for grpc and wazero (SyscallConn, Dialer.Control, IPConn.Read) net#78 adds client API fields and related compatibility methods.

Full Darwin networking also needs the merged net changes and a later src/net pin update. No upstream merge or current full-suite pass is implied by this list.

Additional independent gaps found in Crier are covered by #5655 (cookie-jar loader merge) and tinygo-org/net#82 (ListenConfig). They do not duplicate the process, TLS, deadline or server-TLS changes above. Current Crier comparison work is separate from its standard-Go release.

Current Crier evidence

The Crier report separates the original size comparison from a new CI-built candidate test. The original stripped Linux ARM64 result is 13,829,248 bytes versus Go's 30,277,794 bytes. Two render fixtures exceed pixel tolerance.

Candidate e7d34c8c126e0eecd2ce711915f2f88d112d833a, with net 0f460803, passed all 24 fork CI checks. Its downloaded compiler artifacts, with no source overlays, build unchanged Crier 7edaff9. Linux ARM64 E2E passed 143 cases with no failures or skips. Darwin ARM64 passed 142 with no failures and one platform trust-store skip. Darwin startup now works. A separate Darwin local-TLS matrix passes certificate rejection, plaintext refusal, update to a Go 1.1.0 target, and offline rollback. Both platforms pass spawn, signal, cookiejar, os/fcntl, and network probes.

These are combined-candidate results, not proof that this PR alone supplies all features. No new pixel or stripped-size comparison, amd64 execution, or current Dispat acceptance is claimed. WaitDelay and the recorded net limits remain open. No fork release was published.