bazelrc-parser-go

This repository contains a parser for bazelrc files written in Go.

It is limited in its accuracy, as it is providing mostly syntactic parsing, and does not have a full awareness of how Bazel itself parses config (which also changes over time).

Some of its known limitations:

• It treats config-gated settings as independent commands, including platform-specific configs (i.e. build:remote --jobs=100 is independent of build --jobs=200).
• It does not understand what settings accumulate multiple uses (i.e. it doesn't know that foo is relevant in build --extra_toolchains=foo --extra_toolchains=bar).
• It does not know about the types of values that are expected, so e.g. doesn't know that boolean flags may coerce 0 and 1 to false and true.
• Its handling of spaces inside flags (e.g. --copt="--foo --bar") may not exactly match Bazel's.

There's plausibly a space for expanding the bazel canonicalize-flags command to make this library obsolete. Some of the limitations of bazel canonicalize-flags are:

• It require invoking bazel (and require setting up a whole server so is slow, requires the server lock, and may invalidate the analysis cache if not done very carefully)
• It doesn't support reading from .bazelrc files at all, so pre-processing would still need to be done to load the flags to pass them to bazel.
  • Also, there isn't an easy way to support --config flags, and the order of priority of handling flags enabled by --config is one of the more fiddly parts of flag parsing.
• bazel canonicalize-flags will error if targets are specified (i.e. bazel canonicalize-flags -- --jobs=10 //:gazelle will error), so these would need detecting and stripping out.
• bazel canonicalize-flags doesn't provide structured output, just "flag per line", which causes issues for e.g. copts containing newlines.