Tcl help ...

Joshua Root jmr at
Mon Mar 29 20:40:27 UTC 2021

On 2021-3-30 06:35 , Christopher Jones wrote:
> Hi All,
> Working on fixing a build issue and hitting a limit in my current 
> understanding of Tcl… I am trying to set some new env vars in the build.env
>          set ldflags ${configure.ldflags}
>          build.env-append   GO_EXTLINK_ENABLED=1
>          build.env-append   GO_LDFLAGS='-extldflags\=$ldflags’
> however, when the port in question using ${build.env} I get
> DEBUG: system -W 
> /opt/local/var/macports/build/_Users_chris_Projects_MacPorts_ports_devel_codesearch/codesearch/work/gopath/src/ 
> <> 
> GOPATH=/opt/local/var/macports/build/_Users_chris_Projects_MacPorts_ports_devel_codesearch/codesearch/work/gopath 
> GOARCH=amd64 GOOS=darwin CC=/usr/bin/clang CXX=/usr/bin/clang++ 
> GOPROXY=off GO111MODULE=off 
> C_INCLUDE_PATH=/opt/local/include/LegacySupport 
> OBJC_INCLUDE_PATH=/opt/local/include/LegacySupport 
> CPLUS_INCLUDE_PATH=/opt/local/include/LegacySupport 
> OBJCPLUS_INCLUDE_PATH=/opt/local/include/LegacySupport 
> GO_EXTLINK_ENABLED=1 {GO_LDFLAGS='-extldflags=-L/opt/local/lib 
> -Wl,-headerpad_max_install_names -lMacportsLegacySupport'} 
> /opt/local/bin/go build cmd/cgrep/cgrep.go
> sh: {GO_LDFLAGS=-extldflags=-L/opt/local/lib 
> -Wl,-headerpad_max_install_names -lMacportsLegacySupport}:

That isn't a result of setting build.env. You must have added this to 
build.args or similar.

> See how the second env var I define above is shown inside {} braces, 
> which of course sh cannot parse.
> I have tried numerous forms of how to set
> build.env-append   GO_LDFLAGS='-extldflags\=$ldflags’
> but they all have the same issue.
> I suspect this is just my lack of really undertanding quoting in tcl, so 
> I am hoping someone can tell me what I am doing wrong ?

Do you want literal single quotes in the value of the environment 
variable? If so:

build.env-append   GO_LDFLAGS='-extldflags=${configure.ldflags}’

if not:

build.env-append   GO_LDFLAGS=-extldflags=${configure.ldflags}

The value of the *.env options never gets passed to a shell; the 
environment variables are set directly by our code. The parsing is very 
simple, perhaps deceptively so if you expect it to work like a shell. 
Each list element is expected to contain a single assignment, with 
everything before the first '=' used as the variable name, and 
everything after it used as the value to set it to.

A corollary is that something like this won't (in general) work:

build.args-append ${build.env}

because build.args has to deal with shell quoting. There's also a second 
bug in that line because it appends the entirety of build.env, which is 
a list, as a single element. The {*} operator is essential when doing 
something like this:

build.args foo bar
destroot.args-append {*}${build.args}

- Josh

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