cli: enable fileset by default

I've tested it for months and found no problems.

CHANGELOG.md

@@ -23,6 +23,9 @@ to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 * Updated defaults for graph node symbol templates `templates.log_node` and
   `templates.op_log_node`.
 
+* [The "fileset" language](docs/filesets.md) is now enabled by default. It can
+  still be disable by setting `ui.allow-filesets=false`.
+
 ### Deprecations
 
 ### New features

cli/src/config/misc.toml

@@ -9,7 +9,8 @@ unamend = ["unsquash"]
 tree-level-conflicts = true
 
 [ui]
-allow-filesets = false
+# TODO: delete ui.allow-filesets in jj 0.26+
+allow-filesets = true
 always-allow-large-revsets = false
 diff-instructions = true
 paginate = "auto"

cli/tests/test_diff_command.rs

@@ -198,15 +198,7 @@ fn test_diff_basic() {
     "###);
 
     // Filter by glob pattern
-    let stdout = test_env.jj_cmd_success(
-        &repo_path,
-        &[
-            "diff",
-            "--config-toml=ui.allow-filesets=true",
-            "-s",
-            "glob:file[12]",
-        ],
-    );
+    let stdout = test_env.jj_cmd_success(&repo_path, &["diff", "-s", "glob:file[12]"]);
     insta::assert_snapshot!(stdout, @r###"
     D file1
     M file2

cli/tests/test_global_opts.rs

@@ -233,8 +233,6 @@ fn test_bad_path() {
     let subdir = repo_path.join("dir");
     std::fs::create_dir_all(&subdir).unwrap();
 
-    test_env.add_config("ui.allow-filesets = true");
-
     // cwd == workspace_root
     let stderr = test_env.jj_cmd_failure(&repo_path, &["file", "show", "../out"]);
     insta::assert_snapshot!(stderr.replace('\\', "/"), @r###"
@@ -450,8 +448,16 @@ fn test_color_ui_messages() {
     // error source
     let stderr = test_env.jj_cmd_failure(&repo_path, &["log", ".."]);
     insta::assert_snapshot!(stderr.replace('\\', "/"), @r###"
-    Error: Path ".." is not in the repo "."
-    Caused by: Invalid component ".." in repo-relative path "../"
+    Error: Failed to parse fileset: Invalid file pattern
+    Caused by:
+    1:  --> 1:1
+      |
+    1 | ..
+      | ^^
+      |
+      = Invalid file pattern
+    2: Path ".." is not in the repo "."
+    3: Invalid component ".." in repo-relative path "../"
     "###);
 
     // warning

cli/tests/test_log_command.rs

@@ -825,18 +825,22 @@ fn test_log_filtered_by_path() {
     A file2
     "###);
 
-    // Fileset/pattern syntax is disabled by default.
+    // Fileset/pattern syntax can be disabled.
     let stderr = test_env.jj_cmd_failure(
         test_env.env_root(),
-        &["log", "-R", repo_path.to_str().unwrap(), "all()"],
+        &[
+            "log",
+            "--config-toml=ui.allow-filesets=false",
+            "-R",
+            repo_path.to_str().unwrap(),
+            "all()",
+        ],
     );
     insta::assert_snapshot!(stderr.replace('\\', "/"), @r###"
     Error: Path "all()" is not in the repo "repo"
     Caused by: Invalid component ".." in repo-relative path "../all()"
     "###);
 
-    test_env.add_config("ui.allow-filesets = true");
-
     // empty revisions are filtered out by "all()" fileset.
     let stdout = test_env.jj_cmd_success(&repo_path, &["log", "-Tdescription", "-s", "all()"]);
     insta::assert_snapshot!(stdout, @r###"

docs/filesets.md

@@ -5,13 +5,6 @@ Expressions in this language are called "filesets" (the idea comes from
 [Mercurial](https://repo.mercurial-scm.org/hg/help/filesets)). The language
 consists of file patterns, operators, and functions.
 
-**Filesets support is still experimental.** It can be enabled by
-`ui.allow-filesets`.
-
-```toml
-ui.allow-filesets = true
-```
-
 Many `jj` commands accept fileset expressions as positional arguments. File
 names passed to these commands [must be quoted][string-literals] if they contain
 whitespace or meta characters. However, as a special case, quotes can be omitted