fix: follows symbolic links with formatter exclusion paths

[chandler-solo]

ln -s worktree wt && cd wt && golangci-lint fmt now works

[CLAassistant]

All committers have signed the CLA.

[boring-cyborg]

Hey, thank you for opening your first Pull Request !

[ldez]

The problem supposedly fixed by this PR "issue with the 'fmt' command and symbolic links" is not fixed.

At first, I was thinking the PR title was wrong because the only change was in the exclusions system.
So I made some changes to fit that assumption.

But in fact, this PR fixes nothing, because the problem with symlinks is not here.

This is why it's better to open an issue before opening a PR, and when opening a PR, a real description is important.

I close this PR, and I will try to create the real fix.

[chandler-solo]

ln -s worktree wt && cd wt && golangci-lint fmt

This is how to reproduce, on MacOS 15.7.1, with golangci-lint 2.6.1. You can work around the issue with golangci-lint fmt $(pwd -P)

This has nothing to do with formatter exclusion paths. My test case fails on main and passes with my changes.

[ldez]

Your commit is only modifying RunnerOptions.MatchAnyPattern method.

1. This method is only related to formatter exclusion paths (patterns -> cfg.Formatters.Exclusions.Paths).
   If there is no pattern (exclusion paths), this method is skipped.

golangci-lint/pkg/goformat/runner.go

Lines 236 to 244 in 7bcb236

	for _, pattern := range cfg.Formatters.Exclusions.Paths {
	exp, err := regexp.Compile(fsutils.NormalizePathInRegex(pattern))
	if err != nil {
	return RunnerOptions{}, fmt.Errorf("compile path pattern %q: %w", pattern, err)
	}
	opts.patterns = append(opts.patterns, exp)
	opts.excludedPathCounter[exp] = 0
	}

golangci-lint/pkg/goformat/runner.go

Lines 250 to 252 in 7bcb236

	if len(o.patterns) == 0 {
	return false, nil
	}

2. Your comment The basePath is already resolved via fsutils.Getwd() in NewRunnerOptions. is wrong: fsutils.Getwd() is only called when wd mode is used. This mode is only one of the four modes (and not the default).

golangci-lint/pkg/fsutils/basepath.go

Lines 56 to 57 in 7bcb236

	case RelativePathModeWd:
	wd, err := Getwd()

3. All the tests, inside your commit, are only testing formatter exclusion paths, and in the wrong way by playing with unexposed fields.

A concrete reproducer

#!/bin/sh -e

ROOT=$(mktemp -d)
mkdir -p $ROOT/project/

## Create module
cat > $ROOT/project/go.mod <<EOF
module github.com/golangci/sandbox

go1.24.0
EOF

# Create golangci-lint configuration file.
cat > $ROOT/project/.golangci.yaml <<EOF
version: "2"

formatters:
  enable:
    - gofmt
EOF

## Create main.go file.
cat > $ROOT/project/main.go <<EOF
package main

import "fmt"

func main() {
fmt.Println("hello world") // Formatting problem.
}
EOF

## Create symlink to the project directory.
ln -s $ROOT/project/ $ROOT/workdir


## Run golangci-lint inside the real project directory.
cd $ROOT/project

echo
echo "--------------------------"
echo "Run on the real project directory ($(pwd)):"
echo

golangci-lint fmt --diff || true

## Run golangci-lint inside the symlinked project directory.
cd $ROOT/workdir

echo
echo "--------------------------"
echo "Run on the symlinked project directory ($(pwd)):"
echo

golangci-lint fmt --diff || true

rm -rf $ROOT

$ ./setup.sh

--------------------------
Run on the real project directory (/tmp/tmp.5C7AJyRYRC/project):

diff /tmp/tmp.5C7AJyRYRC/project/main.go.orig /tmp/tmp.5C7AJyRYRC/project/main.go
--- /tmp/tmp.5C7AJyRYRC/project/main.go.orig
+++ /tmp/tmp.5C7AJyRYRC/project/main.go
@@ -3,5 +3,5 @@
 import "fmt"
 
 func main() {
-fmt.Println("hello world") // Formatting problem.
+       fmt.Println("hello world") // Formatting problem.
 }

--------------------------
Run on the symlinked project directory (/tmp/tmp.5C7AJyRYRC/workdir):

$

I will create a PR with the real fix.

[chandler-solo]

That is the perfect reproducer. I'll open an issue next time with a real reproducer.