feat(format): Add ability to ignore files (#210)

* feat: remove golangci-lint (#207)

In preparation for 1.0, we want all linters to work correctly.
In the discussion for #129 we decided that is a fatal bug, and no one is able to fix it in the short term.

We're happy to add Go linting back to rules_lint when someone has a correct implementation that handles transitive srcs.
The code will still be here in the git history when it's time to revive it.

Closes #129

* Move changes from linting.md to formatting.md

* Address review comments

---------

Co-authored-by: Alex Eagle <[email protected]>

Author: mrmeku

docs/formatting.md

@@ -79,6 +79,17 @@ Assuming you installed with the typical layout:
 
 `bazel run //:format some/file.md other/file.json`
 
+### Ignoring files explicitly
+
+Commonly, the underlying formatters that rules_lint invokes provide their own methods of excluding files (.prettierignore for example). At times when that is not the case, rules_lint provides its
+own escape hatch to exclude files from linting using attributes specified via [`.gitattributes` files](https://git-scm.com/docs/gitattributes).
+
+If any of following attributes are set on a file it will be excluded:
+
+- `rules-lint-ignored`
+- `gitlab-generated`
+- `linguist-generated`
+
 ### Install as a pre-commit hook
 
 If you use [pre-commit.com](https://pre-commit.com/), add this in your `.pre-commit-config.yaml`:

example/.gitattributes

@@ -0,0 +1,7 @@
+# Do not try and format generated code
+pnpm-lock.yaml linguist-generated
+
+# Any of the below attributes can be set to ignore a file
+src/subdir/rules-lint-ignored.js rules-lint-ignored
+src/subdir/gitlab-generated.js gitlab-generated
+src/subdir/linguist-generated.js linguist-generated

example/src/subdir/gitlab-generated.js

@@ -0,0 +1,3 @@
+// Ignored by https://github.com/aspect-build/rules_lint/blob/example/.gitattributes
+  export var x = "white space issue and no semi colon"
+  

example/src/subdir/linguist-generated.js

@@ -0,0 +1,3 @@
+// Ignored by https://github.com/aspect-build/rules_lint/blob/example/.gitattributes
+  export var x = "white space issue and no semi colon"
+  

example/src/subdir/rules-lint-ignored.js

@@ -94,9 +94,18 @@ function ls-files {
 
         # TODO: determine which staged changes we should format; avoid formatting unstaged changes
         # TODO: try to format only modified regions of the file (where supported)
-        git ls-files --cached --modified --other --exclude-standard "${patterns[@]}" "${patterns[@]/#/*/}" | {
-          grep -vE "^$(git ls-files --deleted)$" || true;
-        }
+        files=$(git ls-files --cached --modified --other --exclude-standard "${patterns[@]}" "${patterns[@]/#/*/}" | {
+          grep -vE \
+            "^$(git ls-files --deleted)$" \
+          || true;
+        })
+        git_attributes=$(git check-attr -a -- $files)
+        for file in $files; do
+            # Check if any of the attributes we ignore are set for this file.
+            if ! grep -qE "(^| )$file: (rules-lint-ignored|linguist-generated|gitlab-generated): set($| )" <<< $git_attributes; then
+                echo $file
+            fi
+        done
     else
         # When given arguments, they are glob patterns of the superset of files to format.
         # We just need to filter those so we only select files for this language