Disable --//bazel:use_local_flex_bison that won't work with bazel 8

.github/workflows/verible-ci.yml

@@ -397,7 +397,6 @@ jobs:
     - name: Install dependencies
       run: |
         choco install bazel --force --version=7.6.1
-        choco install winflexbison3
         choco install llvm --allow-downgrade --version=20.1.4
 
     - name: Debug bazel directory settings

MODULE.bazel

@@ -9,11 +9,11 @@ bazel_dep(name = "nlohmann_json", version = "3.11.3.bcr.1")
 bazel_dep(name = "platforms", version = "0.0.11")
 bazel_dep(name = "protobuf", version = "31.0-rc2")
 bazel_dep(name = "re2", version = "2024-07-02.bcr.1")
-bazel_dep(name = "rules_bison", version = "0.3")
+bazel_dep(name = "rules_bison", version = "0.4")
 bazel_dep(name = "rules_cc", version = "0.1.2")
-bazel_dep(name = "rules_flex", version = "0.3")
+bazel_dep(name = "rules_flex", version = "0.4")
 bazel_dep(name = "rules_license", version = "1.0.0")
-bazel_dep(name = "rules_m4", version = "0.2.3")
+bazel_dep(name = "rules_m4", version = "0.3")
 bazel_dep(name = "zlib", version = "1.3.1.bcr.5")
 
 bazel_dep(name = "googletest", version = "1.15.2", dev_dependency = True)

README.md

@@ -201,18 +201,11 @@ instead of default `gold` linker).
 bazel build -c opt --config=create_static_linked_executables //...
 ```
 
-### Optionally using local flex/bison for build
+### Deprecated: using local flex/bison for build
 
-Flex and Bison, that are needed for the parser generation, are compiled as part
-of the build process. But if for any reason you want or need local tools (e.g.
-if you encounter a compile problem with them - please file a bug then)
-can choose so by adding `--//bazel:use_local_flex_bison` to your bazel
-command line:
-
-```bash
-# Also append the option '--//bazel:use_local_flex_bison' to test/install commands
-bazel build -c opt  --//bazel:use_local_flex_bison //...
-```
+There used to be `--//bazel:use_local_flex_bison`, but it has been disabled
+as it won't work with
+[bazel 8](https://github.com/chipsalliance/verible/issues/2435).
 
 ### Building on Windows
 

bazel/BUILD

@@ -30,11 +30,7 @@ exports_files([
 bool_flag(
     name = "use_local_flex_bison",
     build_setting_default = False,
-)
-
-config_setting(
-    name = "use_local_flex_bison_enabled",
-    flag_values = {":use_local_flex_bison": "true"},
+    deprecation = "This flag has been disabled; see https://github.com/chipsalliance/verible/issues/2435 if you want to help fix re-enable it.",
 )
 
 bool_flag(

bazel/bison.bzl

@@ -30,17 +30,9 @@ def genyacc(
         name = name,
         srcs = [src],
         outs = [header_out, source_out] + extra_outs,
-        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) + " $<",
-        }),
-        toolchains = select({
-            "//bazel:use_local_flex_bison_enabled": [],
-            "@platforms//os:windows": [],
-            "//conditions:default": [
-                "@rules_bison//bison:current_bison_toolchain",
-                "@rules_m4//m4:current_m4_toolchain",
-            ],
-        }),
+        cmd = "M4=$(M4) $(BISON) --defines=$(location " + header_out + ") --output-file=$(location " + source_out + ") " + " ".join(extra_options) + " $<",
+        toolchains = [
+            "@rules_bison//bison:current_bison_toolchain",
+            "@rules_m4//m4:current_m4_toolchain",
+        ],
     )

bazel/flex.bzl

@@ -24,17 +24,9 @@ def genlex(name, src, out):
         name = name,
         srcs = [src],
         outs = [out],
-        cmd = select({
-            "//bazel:use_local_flex_bison_enabled": "flex --outfile=$@ $<",
-            "@platforms//os:windows": "win_flex.exe --outfile=$@ $<",
-            "//conditions:default": "M4=$(M4) $(FLEX) --outfile=$@ $<",
-        }),
-        toolchains = select({
-            "//bazel:use_local_flex_bison_enabled": [],
-            "@platforms//os:windows": [],
-            "//conditions:default": [
-                "@rules_flex//flex:current_flex_toolchain",
-                "@rules_m4//m4:current_m4_toolchain",
-            ],
-        }),
+        cmd = "M4=$(M4) $(FLEX) --outfile=$@ $<",
+        toolchains = [
+            "@rules_flex//flex:current_flex_toolchain",
+            "@rules_m4//m4:current_m4_toolchain",
+        ],
     )

shell.nix

@@ -26,10 +26,6 @@ verible_used_stdenv.mkDerivation {
       # To manually run export_json_examples
       python3Packages.anytree
 
-      # For using --//bazel:use_local_flex_bison if desired
-      flex
-      bison
-
       # To build vscode vsix package
       nodejs