feat: color the human-readable outputs (#333)

* feat: color the human-readable report

add a flag to disable color in cases where the output is presented in a terminal that can't render it

Fixes #332

* chore: fix test

* chore: fix PMD test

* chore: use shorter flag syntax

* chore: code review feedback

example/test/lint_test.bats

@@ -20,7 +20,13 @@ EOF
 	assert_output --partial "src/unused_import.py:13:1: F401 'os' imported but unused"
 
 	# PMD
-	assert_output --partial 'src/Foo.java:9:	FinalizeOverloaded:	Finalize methods should not be overloaded'
+	echo <<"EOF" | assert_output --partial
+* file: src/Foo.java
+    src:  Foo.java:9:9
+    rule: FinalizeOverloaded
+    msg:  Finalize methods should not be overloaded
+    code: protected void finalize(int a) {}
+EOF
 
 	# ktlint
 	assert_output --partial "src/hello.kt:1:1: File name 'hello.kt' should conform PascalCase (standard:filename)"
@@ -42,7 +48,7 @@ EOF
 }
 
 @test "should produce reports" {
-	run $BATS_TEST_DIRNAME/../lint.sh //src:all
+	run $BATS_TEST_DIRNAME/../lint.sh //src:all --no@aspect_rules_lint//lint:color
 	assert_success
 	assert_lints
 

lint/BUILD.bazel

@@ -69,8 +69,23 @@ config_setting(
     flag_values = {":fix": "true"},
 )
 
+bool_flag(
+    name = "color",
+    build_setting_default = True,
+    visibility = ["//visibility:public"],
+)
+
+config_setting(
+    name = "color.enabled",
+    flag_values = {":color": "true"},
+)
+
 lint_options(
     name = "options",
+    color = select({
+        ":color.enabled": True,
+        "//conditions:default": False,
+    }),
     debug = select({
         ":debug.enabled": True,
         "//conditions:default": False,

lint/eslint.bzl

@@ -84,7 +84,7 @@ def _gather_inputs(ctx, srcs, files):
     inputs.extend(js_inputs.to_list())
     return inputs
 
-def eslint_action(ctx, executable, srcs, stdout, exit_code = None, format = "stylish"):
+def eslint_action(ctx, executable, srcs, stdout, exit_code = None, format = "stylish", env = {}):
     """Create a Bazel Action that spawns an eslint process.
 
     Adapter for wrapping Bazel around
@@ -98,6 +98,7 @@ def eslint_action(ctx, executable, srcs, stdout, exit_code = None, format = "sty
         exit_code: output file containing the exit code of eslint.
             If None, then fail the build when eslint exits non-zero.
         format: value for eslint `--format` CLI flag
+        env: environment variables for eslint
     """
 
     args = ctx.actions.args()
@@ -120,9 +121,9 @@ def eslint_action(ctx, executable, srcs, stdout, exit_code = None, format = "sty
             tools = [executable._eslint],
             arguments = [args],
             command = executable._eslint.path + " $@ && touch " + stdout.path,
-            env = {
+            env = dict(env, **{
                 "BAZEL_BINDIR": ctx.bin_dir.path,
-            },
+            }),
             mnemonic = _MNEMONIC,
             progress_message = "Linting %{label} with ESLint",
         )
@@ -138,15 +139,15 @@ def eslint_action(ctx, executable, srcs, stdout, exit_code = None, format = "sty
             outputs = [stdout, exit_code],
             executable = executable._eslint,
             arguments = [args],
-            env = {
+            env = dict(env, **{
                 "BAZEL_BINDIR": ctx.bin_dir.path,
                 "JS_BINARY__EXIT_CODE_OUTPUT_FILE": exit_code.path,
-            },
+            }),
             mnemonic = _MNEMONIC,
             progress_message = "Linting %{label} with ESLint",
         )
 
-def eslint_fix(ctx, executable, srcs, patch, stdout, exit_code, format = "stylish"):
+def eslint_fix(ctx, executable, srcs, patch, stdout, exit_code, format = "stylish", env = {}):
     """Create a Bazel Action that spawns eslint with --fix.
 
     Args:
@@ -157,6 +158,7 @@ def eslint_fix(ctx, executable, srcs, patch, stdout, exit_code, format = "stylis
         stdout: output file containing the stdout or --output-file of eslint
         exit_code: output file containing the exit code of eslint
         format: value for eslint `--format` CLI flag
+        env: environment variaables for eslint
     """
     patch_cfg = ctx.actions.declare_file("_{}.patch_cfg".format(ctx.label.name))
 
@@ -165,7 +167,7 @@ def eslint_fix(ctx, executable, srcs, patch, stdout, exit_code, format = "stylis
         content = json.encode({
             "linter": executable._eslint.path,
             "args": ["--fix", "--format", format] + [s.short_path for s in srcs],
-            "env": {"BAZEL_BINDIR": ctx.bin_dir.path},
+            "env": dict(env, **{"BAZEL_BINDIR": ctx.bin_dir.path}),
             "files_to_diff": [s.path for s in srcs],
             "output": patch.path,
         }),
@@ -176,12 +178,12 @@ def eslint_fix(ctx, executable, srcs, patch, stdout, exit_code, format = "stylis
         outputs = [patch, stdout, exit_code],
         executable = executable._patcher,
         arguments = [patch_cfg.path],
-        env = {
+        env = dict(env, **{
             "BAZEL_BINDIR": ".",
             "JS_BINARY__EXIT_CODE_OUTPUT_FILE": exit_code.path,
             "JS_BINARY__STDOUT_OUTPUT_FILE": stdout.path,
             "JS_BINARY__SILENT_ON_SUCCESS": "1",
-        },
+        }),
         tools = [executable._eslint],
         mnemonic = _MNEMONIC,
         progress_message = "Linting %{label} with ESLint",
@@ -198,11 +200,15 @@ def _eslint_aspect_impl(target, ctx):
     else:
         outputs, info = output_files(_MNEMONIC, target, ctx)
 
+    # https://www.npmjs.com/package/chalk#chalklevel
+    # 2: Force 256 color support even when a tty isn't detected
+    color_env = {"FORCE_COLOR": "2"} if ctx.attr._options[LintOptionsInfo].color else {}
+
     # eslint can produce a patch file at the same time it reports the unpatched violations
     if hasattr(outputs, "patch"):
-        eslint_fix(ctx, ctx.executable, files_to_lint, outputs.patch, outputs.human.out, outputs.human.exit_code)
+        eslint_fix(ctx, ctx.executable, files_to_lint, outputs.patch, outputs.human.out, outputs.human.exit_code, env = color_env)
     else:
-        eslint_action(ctx, ctx.executable, files_to_lint, outputs.human.out, outputs.human.exit_code)
+        eslint_action(ctx, ctx.executable, files_to_lint, outputs.human.out, outputs.human.exit_code, env = color_env)
 
     # TODO(alex): if we run with --fix, this will report the issues that were fixed. Does a machine reader want to know about them?
     eslint_action(ctx, ctx.executable, files_to_lint, outputs.machine.out, outputs.machine.exit_code, format = ctx.attr._formatter)

lint/flake8.bzl

@@ -30,7 +30,7 @@ load("//lint/private:lint_aspect.bzl", "LintOptionsInfo", "filter_srcs", "noop_l
 
 _MNEMONIC = "AspectRulesLintFlake8"
 
-def flake8_action(ctx, executable, srcs, config, stdout, exit_code = None):
+def flake8_action(ctx, executable, srcs, config, stdout, exit_code = None, options = []):
     """Run flake8 as an action under Bazel.
 
     Based on https://flake8.pycqa.org/en/latest/user/invocation.html
@@ -43,13 +43,15 @@ def flake8_action(ctx, executable, srcs, config, stdout, exit_code = None):
         stdout: output file containing stdout of flake8
         exit_code: output file containing exit code of flake8
             If None, then fail the build when flake8 exits non-zero.
+        options: additional command-line options, see https://flake8.pycqa.org/en/latest/user/options.html
     """
     inputs = srcs + [config]
     outputs = [stdout]
 
     # Wire command-line options, see
     # https://flake8.pycqa.org/en/latest/user/options.html
     args = ctx.actions.args()
+    args.add_all(options)
     args.add_all(srcs)
     args.add(config, format = "--config=%s")
 
@@ -84,8 +86,8 @@ def _flake8_aspect_impl(target, ctx):
         noop_lint_action(ctx, outputs)
         return [info]
 
-    # TODO(#332): colorize the human output
-    flake8_action(ctx, ctx.executable._flake8, files_to_lint, ctx.file._config_file, outputs.human.out, outputs.human.exit_code)
+    color_options = ["--color=always"] if ctx.attr._options[LintOptionsInfo].color else []
+    flake8_action(ctx, ctx.executable._flake8, files_to_lint, ctx.file._config_file, outputs.human.out, outputs.human.exit_code, color_options)
     flake8_action(ctx, ctx.executable._flake8, files_to_lint, ctx.file._config_file, outputs.machine.out, outputs.machine.exit_code)
     return [info]