Improved Linguist compatibility

Recognise the `linguist-documentation` and `linguist-detectable`
attributes in `.gitattributes` files, and use them in
`GetLanguageStats()` to make a decision whether to include a particular
file in the stats or not.

This allows one more control over which files in their repositories
contribute toward the language statistics, so that for a project that is
mostly documentation, the language stats can reflect that.

Fixes #1672.

Signed-off-by: Gergely Nagy <forgejo@gergo.csillger.hu>

tests/integration/repo_lang_stats_test.go

@@ -0,0 +1,276 @@
+// Copyright 2024 The Forgejo Authors c/o Codeberg e.V.. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package integration
+
+import (
+	"context"
+	"net/url"
+	"strings"
+	"testing"
+	"time"
+
+	"code.gitea.io/gitea/models/db"
+	repo_model "code.gitea.io/gitea/models/repo"
+	"code.gitea.io/gitea/models/unittest"
+	user_model "code.gitea.io/gitea/models/user"
+	"code.gitea.io/gitea/modules/git"
+	"code.gitea.io/gitea/modules/indexer/stats"
+	"code.gitea.io/gitea/modules/queue"
+	repo_service "code.gitea.io/gitea/services/repository"
+	files_service "code.gitea.io/gitea/services/repository/files"
+	"code.gitea.io/gitea/tests"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func createLangStatTestRepo(t *testing.T) (*repo_model.Repository, func()) {
+	t.Helper()
+
+	user2 := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: 2})
+
+	// Create a new repository
+	repo, err := repo_service.CreateRepository(db.DefaultContext, user2, user2, repo_service.CreateRepoOptions{
+		Name:          "lang-stat-test",
+		Description:   "minimal repo for language stats testing",
+		AutoInit:      true,
+		Gitignores:    "Go",
+		License:       "MIT",
+		Readme:        "Default",
+		DefaultBranch: "main",
+		IsPrivate:     false,
+	})
+	assert.NoError(t, err)
+	assert.NotEmpty(t, repo)
+
+	return repo, func() {
+		repo_service.DeleteRepository(db.DefaultContext, user2, repo, false)
+	}
+}
+
+func addLangStatTestFiles(t *testing.T, repo *repo_model.Repository, contents string) string {
+	t.Helper()
+
+	owner := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: repo.OwnerID})
+
+	addFilesResp, err := files_service.ChangeRepoFiles(git.DefaultContext, repo, owner, &files_service.ChangeRepoFilesOptions{
+		Files: []*files_service.ChangeRepoFile{
+			{
+				Operation:     "create",
+				TreePath:      ".gitattributes",
+				ContentReader: strings.NewReader(contents),
+			},
+			{
+				Operation:     "create",
+				TreePath:      "docs.md",
+				ContentReader: strings.NewReader("This **is** a `markdown` file.\n"),
+			},
+			{
+				Operation:     "create",
+				TreePath:      "foo.c",
+				ContentReader: strings.NewReader(`#include <stdio.h>\nint main() {\n  printf("Hello world!\n");\n  return 0;\n}\n`),
+			},
+			{
+				Operation:     "create",
+				TreePath:      "foo.nib",
+				ContentReader: strings.NewReader("Pinky promise, this is not a generated file!\n"),
+			},
+			{
+				Operation:     "create",
+				TreePath:      ".dot.pas",
+				ContentReader: strings.NewReader("program Hello;\nbegin\n  writeln('Hello, world.');\nend.\n"),
+			},
+			{
+				Operation:     "create",
+				TreePath:      "cpplint.py",
+				ContentReader: strings.NewReader(`#! /usr/bin/env python\n\nprint("Hello world!")\n`),
+			},
+			{
+				Operation:     "create",
+				TreePath:      "some-file.xml",
+				ContentReader: strings.NewReader(`<?xml version="1.0"?>\n<foo>\n <bar>Hello</bar>\n</foo>\n`),
+			},
+		},
+		Message:   "add files",
+		OldBranch: "main",
+		NewBranch: "main",
+		Author: &files_service.IdentityOptions{
+			Name:  owner.Name,
+			Email: owner.Email,
+		},
+		Committer: &files_service.IdentityOptions{
+			Name:  owner.Name,
+			Email: owner.Email,
+		},
+		Dates: &files_service.CommitDateOptions{
+			Author:    time.Now(),
+			Committer: time.Now(),
+		},
+	})
+	assert.NoError(t, err)
+	assert.NotEmpty(t, addFilesResp)
+
+	return addFilesResp.Commit.SHA
+}
+
+func TestRepoLangStats(t *testing.T) {
+	onGiteaRun(t, func(t *testing.T, u *url.URL) {
+		/******************
+		 ** Preparations **
+		 ******************/
+		prep := func(t *testing.T, attribs string) (*repo_model.Repository, string, func()) {
+			t.Helper()
+
+			repo, f := createLangStatTestRepo(t)
+			sha := addLangStatTestFiles(t, repo, attribs)
+
+			return repo, sha, f
+		}
+
+		getFreshLanguageStats := func(t *testing.T, repo *repo_model.Repository, sha string) repo_model.LanguageStatList {
+			t.Helper()
+
+			err := stats.UpdateRepoIndexer(repo)
+			assert.NoError(t, err)
+
+			assert.NoError(t, queue.GetManager().FlushAll(context.Background(), 10*time.Second))
+
+			status, err := repo_model.GetIndexerStatus(db.DefaultContext, repo, repo_model.RepoIndexerTypeStats)
+			assert.NoError(t, err)
+			assert.Equal(t, sha, status.CommitSha)
+			langs, err := repo_model.GetTopLanguageStats(db.DefaultContext, repo, 5)
+			assert.NoError(t, err)
+
+			return langs
+		}
+
+		/***********
+		 ** Tests **
+		 ***********/
+
+		// 1. By default, documentation is not indexed
+		t.Run("default", func(t *testing.T) {
+			defer tests.PrintCurrentTest(t)()
+
+			repo, sha, f := prep(t, "")
+			defer f()
+
+			langs := getFreshLanguageStats(t, repo, sha)
+
+			// While this is a fairly short test, this exercises a number of
+			// things:
+			//
+			// - `.gitattributes` is empty, so `isDetectable.IsFalse()`,
+			//   `isVendored.IsTrue()`, and `isDocumentation.IsTrue()` will be
+			//   false for every file, because these are only true if an
+			//   attribute is explicitly set.
+			//
+			// - There is `.dot.pas`, which would be considered Pascal source,
+			//   but it is a dotfile (thus, `enry.IsDotFile()` applies), and as
+			//   such, is not considered.
+			//
+			// - `some-file.xml` will be skipped because Enry considers XML
+			//   configuration, and `enry.IsConfiguration()` will catch it.
+			//
+			// - `!isVendored.IsFalse()` evaluates to true, so
+			//   `analyze.isVendor()` will be called on `cpplint.py`, which will
+			//   be considered vendored, even though both the filename and
+			//   contents would otherwise make it Python.
+			//
+			// - `!isDocumentation.IsFalse()` evaluates to true, so
+			//   `enry.IsDocumentation()` will be called for `docs.md`, and will
+			//   be considered documentation, thus, skipped.
+			//
+			// Thus, this exercises all of the conditions in the first big if
+			// that is supposed to filter out files early. With two short asserts!
+
+			assert.Len(t, langs, 1)
+			assert.Equal(t, "C", langs[0].Language)
+		})
+
+		// 2. Marking foo.c as non-detectable
+		t.Run("foo.c non-detectable", func(t *testing.T) {
+			defer tests.PrintCurrentTest(t)()
+
+			repo, sha, f := prep(t, "foo.c linguist-detectable=false\n")
+			defer f()
+
+			langs := getFreshLanguageStats(t, repo, sha)
+			assert.Empty(t, langs)
+		})
+
+		// 3. Marking Markdown detectable
+		t.Run("detectable markdown", func(t *testing.T) {
+			defer tests.PrintCurrentTest(t)()
+
+			repo, sha, f := prep(t, "*.md linguist-detectable\n")
+			defer f()
+
+			langs := getFreshLanguageStats(t, repo, sha)
+			assert.Len(t, langs, 2)
+			assert.Equal(t, "C", langs[0].Language)
+			assert.Equal(t, "Markdown", langs[1].Language)
+		})
+
+		// 4. Marking foo.c as documentation
+		t.Run("foo.c as documentation", func(t *testing.T) {
+			defer tests.PrintCurrentTest(t)()
+
+			repo, sha, f := prep(t, "foo.c linguist-documentation\n")
+			defer f()
+
+			langs := getFreshLanguageStats(t, repo, sha)
+			assert.Empty(t, langs)
+		})
+
+		// 5. Overriding a generated file
+		t.Run("linguist-generated=false", func(t *testing.T) {
+			defer tests.PrintCurrentTest(t)()
+
+			repo, sha, f := prep(t, "foo.nib linguist-generated=false\nfoo.nib linguist-language=Perl\n")
+			defer f()
+
+			langs := getFreshLanguageStats(t, repo, sha)
+			assert.Len(t, langs, 2)
+			assert.Equal(t, "C", langs[0].Language)
+			assert.Equal(t, "Perl", langs[1].Language)
+		})
+
+		// 6. Disabling vendoring for a file
+		t.Run("linguist-vendored=false", func(t *testing.T) {
+			defer tests.PrintCurrentTest(t)()
+
+			repo, sha, f := prep(t, "cpplint.py linguist-vendored=false\n")
+			defer f()
+
+			langs := getFreshLanguageStats(t, repo, sha)
+			assert.Len(t, langs, 2)
+			assert.Equal(t, "C", langs[0].Language)
+			assert.Equal(t, "Python", langs[1].Language)
+		})
+
+		// 7. Disabling vendoring for a file, with -linguist-vendored
+		t.Run("-linguist-vendored", func(t *testing.T) {
+			defer tests.PrintCurrentTest(t)()
+
+			repo, sha, f := prep(t, "cpplint.py -linguist-vendored\n")
+			defer f()
+
+			langs := getFreshLanguageStats(t, repo, sha)
+			assert.Len(t, langs, 2)
+			assert.Equal(t, "C", langs[0].Language)
+			assert.Equal(t, "Python", langs[1].Language)
+		})
+
+		// 8. Marking foo.c as vendored
+		t.Run("foo.c as vendored", func(t *testing.T) {
+			defer tests.PrintCurrentTest(t)()
+
+			repo, sha, f := prep(t, "foo.c linguist-vendored\n")
+			defer f()
+
+			langs := getFreshLanguageStats(t, repo, sha)
+			assert.Empty(t, langs)
+		})
+	})
+}