Flex and Bison toolchain switching stopped working with bazel 8

[hzeller]

To be able to switch to a local --//bazel:use_local_flex_bison

we switch toolchains accordingly

verible/bazel/bison.bzl

Lines 33 to 37 in 98bdb38

	cmd = select({
	"//bazel:use_local_flex_bison_enabled": "bison --defines=$(location " + header_out + ") --output-file=$(location " + source_out + ") " + " ".join(extra_options) + " $<",
	"@platforms//os:windows": "win_bison.exe --defines=$(location " + header_out + ") --output-file=$(location " + source_out + ") " + " ".join(extra_options) + " $<",
	"//conditions:default": "M4=$(M4) $(BISON) --defines=$(location " + header_out + ") --output-file=$(location " + source_out + ") " + " ".join(extra_options) + " $<",
	}),

verible/bazel/flex.bzl

Lines 27 to 31 in 98bdb38

	cmd = select({
	"//bazel:use_local_flex_bison_enabled": "flex --outfile=$@ $<",
	"@platforms//os:windows": "win_flex.exe --outfile=$@ $<",
	"//conditions:default": "M4=$(M4) $(FLEX) --outfile=$@ $<",
	}),

This stopped working with bazel 8

ERROR: verible/verilog/parser/BUILD:20:7: //verible/verilog/parser:verilog-lex: attribute "toolchains" is not configurable
ERROR: verible/verible/verilog/parser/BUILD:95:8: //verible/verilog/parser:verilog-y: attribute "toolchains" is not configurable

So for now, let's force bazelversion to 7.x, but ideally this could be reformulated in a way that it works with bazel 7 and 8

[hzeller]

if there is anyone with bazel knowledge who'd like to help: highly appreciated.

[mneilly]

FYI - if you are using bazelisk you'll either need to 'touch WORKSPACE' or install the latest version and create a .bazeliskrc file containing USE_BAZEL_VERSION=7.6.0

bazelbuild/bazelisk#52

[hzeller]

I just use bazel directly. Bazelisk downloads binaries that may or may not work on the target platform (e.g. nixos).