rustdoc/doctest/
runner.rs

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1use std::fmt::Write;
2
3use rustc_data_structures::fx::FxIndexSet;
4use rustc_span::edition::Edition;
5
6use crate::doctest::{
7    DocTestBuilder, GlobalTestOptions, IndividualTestOptions, RunnableDocTest, RustdocOptions,
8    ScrapedDocTest, TestFailure, UnusedExterns, run_test,
9};
10use crate::html::markdown::{Ignore, LangString};
11
12/// Convenient type to merge compatible doctests into one.
13pub(crate) struct DocTestRunner {
14    crate_attrs: FxIndexSet<String>,
15    ids: String,
16    output: String,
17    output_merged_tests: String,
18    supports_color: bool,
19    nb_tests: usize,
20}
21
22impl DocTestRunner {
23    pub(crate) fn new() -> Self {
24        Self {
25            crate_attrs: FxIndexSet::default(),
26            ids: String::new(),
27            output: String::new(),
28            output_merged_tests: String::new(),
29            supports_color: true,
30            nb_tests: 0,
31        }
32    }
33
34    pub(crate) fn add_test(
35        &mut self,
36        doctest: &DocTestBuilder,
37        scraped_test: &ScrapedDocTest,
38        target_str: &str,
39    ) {
40        let ignore = match scraped_test.langstr.ignore {
41            Ignore::All => true,
42            Ignore::None => false,
43            Ignore::Some(ref ignores) => ignores.iter().any(|s| target_str.contains(s)),
44        };
45        if !ignore {
46            for line in doctest.crate_attrs.split('\n') {
47                self.crate_attrs.insert(line.to_string());
48            }
49        }
50        self.ids.push_str(&format!(
51            "tests.push({}::TEST);\n",
52            generate_mergeable_doctest(
53                doctest,
54                scraped_test,
55                ignore,
56                self.nb_tests,
57                &mut self.output,
58                &mut self.output_merged_tests,
59            ),
60        ));
61        self.supports_color &= doctest.supports_color;
62        self.nb_tests += 1;
63    }
64
65    pub(crate) fn run_merged_tests(
66        &mut self,
67        test_options: IndividualTestOptions,
68        edition: Edition,
69        opts: &GlobalTestOptions,
70        test_args: &[String],
71        rustdoc_options: &RustdocOptions,
72    ) -> Result<bool, ()> {
73        let mut code = "\
74#![allow(unused_extern_crates)]
75#![allow(internal_features)]
76#![feature(test)]
77#![feature(rustc_attrs)]
78"
79        .to_string();
80
81        let mut code_prefix = String::new();
82
83        for crate_attr in &self.crate_attrs {
84            code_prefix.push_str(crate_attr);
85            code_prefix.push('\n');
86        }
87
88        if opts.attrs.is_empty() {
89            // If there aren't any attributes supplied by #![doc(test(attr(...)))], then allow some
90            // lints that are commonly triggered in doctests. The crate-level test attributes are
91            // commonly used to make tests fail in case they trigger warnings, so having this there in
92            // that case may cause some tests to pass when they shouldn't have.
93            code_prefix.push_str("#![allow(unused)]\n");
94        }
95
96        // Next, any attributes that came from the crate root via #![doc(test(attr(...)))].
97        for attr in &opts.attrs {
98            code_prefix.push_str(&format!("#![{attr}]\n"));
99        }
100
101        code.push_str("extern crate test;\n");
102        writeln!(code, "extern crate doctest_bundle_{edition} as doctest_bundle;").unwrap();
103
104        let test_args = test_args.iter().fold(String::new(), |mut x, arg| {
105            write!(x, "{arg:?}.to_string(),").unwrap();
106            x
107        });
108        write!(
109            code,
110            "\
111{output}
112
113mod __doctest_mod {{
114    use std::sync::OnceLock;
115    use std::path::PathBuf;
116
117    pub static BINARY_PATH: OnceLock<PathBuf> = OnceLock::new();
118    pub const RUN_OPTION: &str = \"RUSTDOC_DOCTEST_RUN_NB_TEST\";
119
120    #[allow(unused)]
121    pub fn doctest_path() -> Option<&'static PathBuf> {{
122        self::BINARY_PATH.get()
123    }}
124
125    #[allow(unused)]
126    pub fn doctest_runner(bin: &std::path::Path, test_nb: usize) -> Result<(), String> {{
127        let out = std::process::Command::new(bin)
128            .env(self::RUN_OPTION, test_nb.to_string())
129            .args(std::env::args().skip(1).collect::<Vec<_>>())
130            .output()
131            .expect(\"failed to run command\");
132        if !out.status.success() {{
133            Err(String::from_utf8_lossy(&out.stderr).to_string())
134        }} else {{
135            Ok(())
136        }}
137    }}
138}}
139
140#[rustc_main]
141fn main() -> std::process::ExitCode {{
142let tests = {{
143    let mut tests = Vec::with_capacity({nb_tests});
144    {ids}
145    tests
146}};
147let test_marker = std::ffi::OsStr::new(__doctest_mod::RUN_OPTION);
148let test_args = &[{test_args}];
149const ENV_BIN: &'static str = \"RUSTDOC_DOCTEST_BIN_PATH\";
150
151if let Ok(binary) = std::env::var(ENV_BIN) {{
152    let _ = crate::__doctest_mod::BINARY_PATH.set(binary.into());
153    unsafe {{ std::env::remove_var(ENV_BIN); }}
154    return std::process::Termination::report(test::test_main(test_args, tests, None));
155}} else if let Ok(nb_test) = std::env::var(__doctest_mod::RUN_OPTION) {{
156    if let Ok(nb_test) = nb_test.parse::<usize>() {{
157        if let Some(test) = tests.get(nb_test) {{
158            if let test::StaticTestFn(f) = &test.testfn {{
159                return std::process::Termination::report(f());
160            }}
161        }}
162    }}
163    panic!(\"Unexpected value for `{{}}`\", __doctest_mod::RUN_OPTION);
164}}
165
166eprintln!(\"WARNING: No rustdoc doctest environment variable provided so doctests will be run in \
167the same process\");
168std::process::Termination::report(test::test_main(test_args, tests, None))
169}}",
170            nb_tests = self.nb_tests,
171            output = self.output_merged_tests,
172            ids = self.ids,
173        )
174        .expect("failed to generate test code");
175        let runnable_test = RunnableDocTest {
176            full_test_code: format!("{code_prefix}{code}", code = self.output),
177            full_test_line_offset: 0,
178            test_opts: test_options,
179            global_opts: opts.clone(),
180            langstr: LangString::default(),
181            line: 0,
182            edition,
183            no_run: false,
184            merged_test_code: Some(code),
185        };
186        let ret =
187            run_test(runnable_test, rustdoc_options, self.supports_color, |_: UnusedExterns| {});
188        if let Err(TestFailure::CompileError) = ret { Err(()) } else { Ok(ret.is_ok()) }
189    }
190}
191
192/// Push new doctest content into `output`. Returns the test ID for this doctest.
193fn generate_mergeable_doctest(
194    doctest: &DocTestBuilder,
195    scraped_test: &ScrapedDocTest,
196    ignore: bool,
197    id: usize,
198    output: &mut String,
199    output_merged_tests: &mut String,
200) -> String {
201    let test_id = format!("__doctest_{id}");
202
203    if ignore {
204        // We generate nothing else.
205        writeln!(output, "pub mod {test_id} {{}}\n").unwrap();
206    } else {
207        writeln!(output, "pub mod {test_id} {{\n{}{}", doctest.crates, doctest.maybe_crate_attrs)
208            .unwrap();
209        if doctest.has_main_fn {
210            output.push_str(&doctest.everything_else);
211        } else {
212            let returns_result = if doctest.everything_else.trim_end().ends_with("(())") {
213                "-> Result<(), impl core::fmt::Debug>"
214            } else {
215                ""
216            };
217            write!(
218                output,
219                "\
220fn main() {returns_result} {{
221{}
222}}",
223                doctest.everything_else
224            )
225            .unwrap();
226        }
227        writeln!(
228            output,
229            "\npub fn __main_fn() -> impl std::process::Termination {{ main() }} \n}}\n"
230        )
231        .unwrap();
232    }
233    let not_running = ignore || scraped_test.langstr.no_run;
234    writeln!(
235        output_merged_tests,
236        "
237mod {test_id} {{
238pub const TEST: test::TestDescAndFn = test::TestDescAndFn::new_doctest(
239{test_name:?}, {ignore}, {file:?}, {line}, {no_run}, {should_panic},
240test::StaticTestFn(
241    || {{{runner}}},
242));
243}}",
244        test_name = scraped_test.name,
245        file = scraped_test.path(),
246        line = scraped_test.line,
247        no_run = scraped_test.langstr.no_run,
248        should_panic = !scraped_test.langstr.no_run && scraped_test.langstr.should_panic,
249        // Setting `no_run` to `true` in `TestDesc` still makes the test run, so we simply
250        // don't give it the function to run.
251        runner = if not_running {
252            "test::assert_test_result(Ok::<(), String>(()))".to_string()
253        } else {
254            format!(
255                "
256if let Some(bin_path) = crate::__doctest_mod::doctest_path() {{
257    test::assert_test_result(crate::__doctest_mod::doctest_runner(bin_path, {id}))
258}} else {{
259    test::assert_test_result(doctest_bundle::{test_id}::__main_fn())
260}}
261",
262            )
263        },
264    )
265    .unwrap();
266    test_id
267}
rustdoc/doctest/runner.rs

rustdoc/doctest/
runner.rs
