Previously, the build ended up embedding an empty string, which made
the shell wrapper rebuild gocross on every invocation. This is still
reasonably fast, but fixing the bypass shaves 80% off gocross's overhead
when no rebuild is needed.
Signed-off-by: David Anderson <danderson@tailscale.com>
A bunch of us invoke tool/go from outside the repo that hosts gocross,
as a way of accessing our version-controlled toolchain. This removes
assumptions from gocross that it's being invoked within the repository
that contains its source code and toolchain configuration.
Fixestailscale/corp#9627
Signed-off-by: David Anderson <danderson@tailscale.com>
This used to make sense, but after a refactor somewhere along the line
this results in trying to download from a malformed URL and generally
confusing failures.
Signed-off-by: David Anderson <danderson@tailscale.com>
Xcode changed how/what data it exports to build steps at some point
recently, so our old way of figuring out the minimum support version
for clang stopped working.
Updates tailscale/corp#4095
Signed-off-by: David Anderson <danderson@tailscale.com>
Sometimes, our cached toolchain ends up being an older version of
Go, older than our go.mod allows. In that scenario, gocross-wrapper.sh
would find a usable toolchain, but then fail to compile gocross.
This change makes the wrapper script check that the cached toolchain's
minor version is good enough to build tailscale.com, and re-bootstraps
in shell if not.
Signed-off-by: David Anderson <danderson@tailscale.com>
This makes gocross and its bootstrap script understand an absolute
path in go.toolchain.rev to mean "use the given toolchain directly".
Signed-off-by: David Anderson <danderson@tailscale.com>
We need to build gocross from multiple repos, but Go's innate
git hash embedding only works when you build gocross from this repo,
not when you build it from elsewhere via 'go build
tailscale.com/tool/gocross'. Instead, explicitly embed the version
found with 'git rev-parse HEAD', which will work from any git repo.
Signed-off-by: David Anderson <danderson@tailscale.com>
This avoids accidentally overwriting variables from the input
environment, which might non-deterministically change the behavior
of gocross.
Signed-off-by: David Anderson <danderson@tailscale.com>
Turns out directing the printed script into the bootstrap location leads
to irritating "text file busy" problems and then having to muck about with
tempfiles and chmod and all that. Instead, have gocross write everything
with the right values.
Signed-off-by: David Anderson <danderson@tailscale.com>
So that when importing and using gocross from other repos, there's
an easy way to get at the right wrapper script that's in sync with
the gocross binary.
Signed-off-by: David Anderson <danderson@tailscale.com>
