feat(report): cargo report timings log discovery logic

Currently look at the newest log file for the workspace.
If not in a workspace, pick the newest log file in the log directory.

Author: weihanglo

src/bin/cargo/commands/report.rs

@@ -1,8 +1,10 @@
 use crate::command_prelude::*;
 
+use cargo::CargoResult;
 use cargo::core::compiler::future_incompat::OnDiskReports;
 use cargo::core::compiler::future_incompat::REPORT_PREAMBLE;
 use cargo::drop_println;
+use cargo::ops;
 
 pub fn cli() -> Command {
     subcommand("report")
@@ -43,7 +45,9 @@ pub fn exec(gctx: &mut GlobalContext, args: &ArgMatches) -> CliResult {
                 "build-analysis",
                 gctx.cli_unstable().build_analysis,
             )?;
-            report_timings(gctx, args)
+            let opts = timings_opts(gctx, args)?;
+            ops::report_timings(gctx, opts)?;
+            Ok(())
         }
         Some((cmd, _)) => {
             unreachable!("unexpected command {}", cmd)
@@ -67,6 +71,11 @@ fn report_future_incompatibilities(gctx: &GlobalContext, args: &ArgMatches) -> C
     Ok(())
 }
 
-fn report_timings(_gctx: &GlobalContext, _args: &ArgMatches) -> CliResult {
-    Ok(())
+fn timings_opts<'a>(
+    gctx: &'a GlobalContext,
+    args: &ArgMatches,
+) -> CargoResult<ops::ReportTimingsOptions<'a>> {
+    let open_result = args.get_flag("open");
+
+    Ok(ops::ReportTimingsOptions { open_result, gctx })
 }

src/cargo/ops/cargo_report/mod.rs

@@ -0,0 +1 @@
+pub mod timings;

src/cargo/ops/cargo_report/timings.rs

@@ -0,0 +1,98 @@
+//! The `cargo report timings` command.
+
+use std::ffi::OsStr;
+use std::fs::File;
+use std::path::PathBuf;
+
+use annotate_snippets::Level;
+use anyhow::Context as _;
+
+use crate::AlreadyPrintedError;
+use crate::CargoResult;
+use crate::GlobalContext;
+use crate::core::Workspace;
+use crate::util::BuildLogger;
+use crate::util::important_paths::find_root_manifest_for_wd;
+use crate::util::logger::RunId;
+
+pub struct ReportTimingsOptions<'gctx> {
+    /// Whether to attempt to open the browser after the report is generated
+    pub open_result: bool,
+    pub gctx: &'gctx GlobalContext,
+}
+
+pub fn report_timings(gctx: &GlobalContext, _opts: ReportTimingsOptions<'_>) -> CargoResult<()> {
+    let ws = find_root_manifest_for_wd(gctx.cwd())
+        .ok()
+        .and_then(|manifest_path| Workspace::new(&manifest_path, gctx).ok());
+    let Some((log, _run_id)) = select_log_file(gctx, ws.as_ref())? else {
+        let title_extra = if let Some(ws) = ws {
+            format!(" for workspace at `{}`", ws.root().display())
+        } else {
+            String::new()
+        };
+        let title = format!("no build log files found{title_extra}");
+        let note = "run command with `-Z build-analysis` to generate log files";
+        let report = [Level::ERROR
+            .primary_title(title)
+            .element(Level::NOTE.message(note))];
+        gctx.shell().print_report(&report, false)?;
+        return Err(AlreadyPrintedError::new(anyhow::anyhow!("")).into());
+    };
+
+    let _f = File::open(&log)
+        .with_context(|| format!("failed to analyze log at `{}`", log.display()))?;
+
+    Ok(())
+}
+
+/// Selects the appropriate log file.
+///
+/// Currently look at the newest log file for the workspace.
+/// If not in a workspace, pick the newest log file in the log directory.
+fn select_log_file(
+    gctx: &GlobalContext,
+    ws: Option<&Workspace<'_>>,
+) -> CargoResult<Option<(PathBuf, RunId)>> {
+    let log_dir = gctx.home().join("log");
+    let log_dir = log_dir.as_path_unlocked();
+
+    if !log_dir.exists() {
+        return Ok(None);
+    }
+
+    // Gets the latest log files in the log directory
+    let mut walk = walkdir::WalkDir::new(log_dir)
+        .follow_links(true)
+        .sort_by(|a, b| a.file_name().cmp(b.file_name()).reverse())
+        .min_depth(1)
+        .max_depth(1)
+        .into_iter()
+        .filter_map(|entry| {
+            let entry = entry.ok()?;
+            let path = entry.path();
+
+            // We only accept JSONL/NDJSON files.
+            if !entry.file_type().is_file() {
+                return None;
+            }
+            if entry.path().extension() != Some(OsStr::new("jsonl")) {
+                return None;
+            }
+
+            // ...and the file name must follow RunId format
+            let run_id = path.file_stem()?.to_str()?.parse::<RunId>().ok()?;
+            Some((entry, run_id))
+        });
+
+    let item = if let Some(ws) = ws {
+        // If we are under a workspace, find only that workspace's log files.
+        let ws_run_id = BuildLogger::generate_run_id(ws);
+        walk.skip_while(|(_, run_id)| !run_id.same_workspace(&ws_run_id))
+            .next()
+    } else {
+        walk.next()
+    };
+
+    Ok(item.map(|(entry, run_id)| (entry.into_path(), run_id)))
+}

src/cargo/ops/mod.rs

@@ -17,6 +17,8 @@ pub use self::cargo_package::check_yanked;
 pub use self::cargo_package::package;
 pub use self::cargo_pkgid::pkgid;
 pub use self::cargo_read_manifest::read_package;
+pub use self::cargo_report::timings::ReportTimingsOptions;
+pub use self::cargo_report::timings::report_timings;
 pub use self::cargo_run::run;
 pub use self::cargo_test::{TestOptions, run_benches, run_tests};
 pub use self::cargo_uninstall::uninstall;
@@ -61,6 +63,7 @@ mod cargo_package;
 mod cargo_pkgid;
 mod cargo_read_manifest;
 pub mod cargo_remove;
+mod cargo_report;
 mod cargo_run;
 mod cargo_test;
 mod cargo_uninstall;

tests/testsuite/cargo_report_timings/mod.rs

@@ -50,7 +50,13 @@ See https://github.com/rust-lang/cargo/issues/15844 for more information about t
 fn no_log() {
     cargo_process("report timings -Zbuild-analysis")
         .masquerade_as_nightly_cargo(&["build-analysis"])
-        .with_stderr_data(str![""])
+        .with_status(101)
+        .with_stderr_data(str![[r#"
+[ERROR] no build log files found
+  |
+  = [NOTE] run command with `-Z build-analysis` to generate log files
+
+"#]])
         .run();
 }
 
@@ -78,7 +84,13 @@ fn no_log_for_the_current_workspace() {
 
     bar.cargo("report timings -Zbuild-analysis")
         .masquerade_as_nightly_cargo(&["build-analysis"])
-        .with_stderr_data(str![""])
+        .with_status(101)
+        .with_stderr_data(str![[r#"
+[ERROR] no build log files found for workspace at `[ROOT]/bar`
+  |
+  = [NOTE] run command with `-Z build-analysis` to generate log files
+
+"#]])
         .run();
 }