Make `code generation` just work

Contributors don't need to learn about `cargo xtask codegen` if `cargo
test` just does the right thing.

8 files changed, 42 insertions, 50 deletions

diff --git a/crates/rust-analyzer/src/config.rs b/crates/rust-analyzer/src/config.rs
index bceca2b0f..078c83f75 100644
--- a/crates/rust-analyzer/src/config.rs
+++ b/crates/rust-analyzer/src/config.rs
@@ -864,7 +864,7 @@ mod tests {
     use super::*;
 
     #[test]
-    fn ensure_schema_in_package_json() {
+    fn generate_package_json_config() {
         let s = Config::json_schema();
         let schema = format!("{:#}", s);
         let mut schema = schema
@@ -895,7 +895,7 @@ mod tests {
     }
 
     #[test]
-    fn schema_in_sync_with_docs() {
+    fn generate_config_documentation() {
         let docs_path = project_root().join("docs/user/generated_config.adoc");
         let current = fs::read_to_string(&docs_path).unwrap();
         let expected = ConfigData::manual();
diff --git a/crates/test_utils/src/lib.rs b/crates/test_utils/src/lib.rs
index 097a54139..dd582c77c 100644
--- a/crates/test_utils/src/lib.rs
+++ b/crates/test_utils/src/lib.rs
@@ -18,7 +18,7 @@ use std::{
 };
 
 use profile::StopWatch;
-use stdx::lines_with_ends;
+use stdx::{is_ci, lines_with_ends};
 use text_size::{TextRange, TextSize};
 
 pub use dissimilar::diff as __diff;
@@ -376,6 +376,9 @@ pub fn try_ensure_file_contents(file: &Path, contents: &str) -> Result<(), ()> {
         "\n\x1b[31;1merror\x1b[0m: {} was not up-to-date, updating\n",
         display_path.display()
     );
+    if is_ci() {
+        eprintln!("\n    NOTE: run `cargo test` locally and commit the updated files\n");
+    }
     if let Some(parent) = file.parent() {
         let _ = std::fs::create_dir_all(parent);
     }
diff --git a/docs/dev/architecture.md b/docs/dev/architecture.md
index ead12616e..0a3fd4285 100644
--- a/docs/dev/architecture.md
+++ b/docs/dev/architecture.md
@@ -308,9 +308,8 @@ This sections talks about the things which are everywhere and nowhere in particu
 ### Code generation
 
 Some of the components of this repository are generated through automatic processes.
-`cargo xtask codegen` runs all generation tasks.
+Generated code is updated automatically on `cargo test`.
 Generated code is generally committed to the git repository.
-There are tests to check that the generated code is fresh.
 
 In particular, we generate:
 
diff --git a/xtask/src/codegen.rs b/xtask/src/codegen.rs
index e3f9ccada..7cdd8f251 100644
--- a/xtask/src/codegen.rs
+++ b/xtask/src/codegen.rs
@@ -7,9 +7,9 @@
 
 mod gen_syntax;
 mod gen_parser_tests;
+mod gen_lint_completions;
 mod gen_assists_docs;
 mod gen_feature_docs;
-mod gen_lint_completions;
 mod gen_diagnostic_docs;
 
 use std::{
@@ -18,38 +18,35 @@ use std::{
 };
 use xshell::{cmd, pushenv, read_file, write_file};
 
-use crate::{ensure_rustfmt, flags, project_root, Result};
+use crate::{ensure_rustfmt, project_root, Result};
 
 pub(crate) use self::{
-    gen_assists_docs::{generate_assists_docs, generate_assists_tests},
-    gen_diagnostic_docs::generate_diagnostic_docs,
-    gen_feature_docs::generate_feature_docs,
-    gen_lint_completions::generate_lint_completions,
-    gen_parser_tests::generate_parser_tests,
-    gen_syntax::generate_syntax,
+    gen_assists_docs::generate_assists_tests, gen_lint_completions::generate_lint_completions,
+    gen_parser_tests::generate_parser_tests, gen_syntax::generate_syntax,
 };
 
+pub(crate) fn docs() -> Result<()> {
+    // We don't commit docs to the repo, so we can just overwrite them.
+    gen_assists_docs::generate_assists_docs(Mode::Overwrite)?;
+    gen_feature_docs::generate_feature_docs(Mode::Overwrite)?;
+    gen_diagnostic_docs::generate_diagnostic_docs(Mode::Overwrite)?;
+    Ok(())
+}
+
+#[allow(unused)]
+fn used() {
+    generate_parser_tests(Mode::Overwrite);
+    generate_assists_tests(Mode::Overwrite);
+    generate_syntax(Mode::Overwrite);
+    generate_lint_completions(Mode::Overwrite);
+}
+
 #[derive(Debug, PartialEq, Eq, Clone, Copy)]
 pub(crate) enum Mode {
     Overwrite,
     Ensure,
 }
 
-impl flags::Codegen {
-    pub(crate) fn run(self) -> Result<()> {
-        if self.features {
-            generate_lint_completions(Mode::Overwrite)?;
-        }
-        generate_syntax(Mode::Overwrite)?;
-        generate_parser_tests(Mode::Overwrite)?;
-        generate_assists_tests(Mode::Overwrite)?;
-        generate_assists_docs(Mode::Overwrite)?;
-        generate_feature_docs(Mode::Overwrite)?;
-        generate_diagnostic_docs(Mode::Overwrite)?;
-        Ok(())
-    }
-}
-
 /// A helper to update file on disk if it has changed.
 /// With verify = false,
 fn update(path: &Path, contents: &str, mode: Mode) -> Result<()> {
diff --git a/xtask/src/flags.rs b/xtask/src/flags.rs
index b39d937ca..48d1ad45e 100644
--- a/xtask/src/flags.rs
+++ b/xtask/src/flags.rs
@@ -27,10 +27,6 @@ xflags::xflags! {
             optional --jemalloc
         }
 
-        cmd codegen {
-            optional --features
-        }
-
         cmd lint {}
         cmd fuzz-tests {}
         cmd pre-cache {}
@@ -67,7 +63,6 @@ pub struct Xtask {
 pub enum XtaskCmd {
     Help(Help),
     Install(Install),
-    Codegen(Codegen),
     Lint(Lint),
     FuzzTests(FuzzTests),
     PreCache(PreCache),
@@ -93,11 +88,6 @@ pub struct Install {
 }
 
 #[derive(Debug)]
-pub struct Codegen {
-    pub features: bool,
-}
-
-#[derive(Debug)]
 pub struct Lint;
 
 #[derive(Debug)]
diff --git a/xtask/src/main.rs b/xtask/src/main.rs
index 25fd32f92..c2dda928e 100644
--- a/xtask/src/main.rs
+++ b/xtask/src/main.rs
@@ -40,7 +40,6 @@ fn main() -> Result<()> {
             return Ok(());
         }
         flags::XtaskCmd::Install(cmd) => cmd.run(),
-        flags::XtaskCmd::Codegen(cmd) => cmd.run(),
         flags::XtaskCmd::Lint(_) => run_clippy(),
         flags::XtaskCmd::FuzzTests(_) => run_fuzzer(),
         flags::XtaskCmd::PreCache(cmd) => cmd.run(),
diff --git a/xtask/src/release.rs b/xtask/src/release.rs
index d8d86fd63..dde5d14ee 100644
--- a/xtask/src/release.rs
+++ b/xtask/src/release.rs
@@ -2,7 +2,7 @@ use std::fmt::Write;
 
 use xshell::{cmd, cp, pushd, read_dir, write_file};
 
-use crate::{codegen, date_iso, flags, is_release_tag, project_root, Mode, Result};
+use crate::{codegen, date_iso, flags, is_release_tag, project_root, Result};
 
 impl flags::Release {
     pub(crate) fn run(self) -> Result<()> {
@@ -12,8 +12,7 @@ impl flags::Release {
             cmd!("git reset --hard tags/nightly").run()?;
             cmd!("git push").run()?;
         }
-        codegen::generate_assists_docs(Mode::Overwrite)?;
-        codegen::generate_feature_docs(Mode::Overwrite)?;
+        codegen::docs()?;
 
         let website_root = project_root().join("../rust-analyzer.github.io");
         let changelog_dir = website_root.join("./thisweek/_posts");
diff --git a/xtask/src/tidy.rs b/xtask/src/tidy.rs
index 3818b9e0f..03b4c0092 100644
--- a/xtask/src/tidy.rs
+++ b/xtask/src/tidy.rs
@@ -12,31 +12,36 @@ use crate::{
 };
 
 #[test]
-fn generated_grammar_is_fresh() {
+fn generate_grammar() {
     codegen::generate_syntax(Mode::Ensure).unwrap()
 }
 
 #[test]
-fn generated_tests_are_fresh() {
+fn generate_parser_tests() {
     codegen::generate_parser_tests(Mode::Ensure).unwrap()
 }
 
 #[test]
-fn generated_assists_are_fresh() {
+fn generate_assists_tests() {
     codegen::generate_assists_tests(Mode::Ensure).unwrap();
 }
 
+/// This clones rustc repo, and so is not worth to keep up-to-date. We update
+/// manually by un-ignoring the test from time to time.
+#[test]
+#[ignore]
+fn generate_lint_completions() {
+    codegen::generate_lint_completions(Mode::Overwrite).unwrap()
+}
+
 #[test]
 fn check_code_formatting() {
     run_rustfmt(Mode::Ensure).unwrap()
 }
 
 #[test]
-fn smoke_test_docs_generation() {
-    // We don't commit docs to the repo, so we can just overwrite in tests.
-    codegen::generate_assists_docs(Mode::Overwrite).unwrap();
-    codegen::generate_feature_docs(Mode::Overwrite).unwrap();
-    codegen::generate_diagnostic_docs(Mode::Overwrite).unwrap();
+fn smoke_test_generate_documentation() {
+    codegen::docs().unwrap()
 }
 
 #[test]