fix(coverage): don't type check (#13324)

This commit changes "deno coverage" command not to type check.

Instead of relying on infrastructure for module loading in "deno run";
the code now directly reaches into cache for original and transpiled
sources. In case sources are not available the error is returned to the
user, suggesting to first run "deno test --coverage" command.

3 files changed, 67 insertions, 34 deletions

diff --git a/cli/file_fetcher.rs b/cli/file_fetcher.rs
index 1c3b093ff..2a7b86727 100644
--- a/cli/file_fetcher.rs
+++ b/cli/file_fetcher.rs
@@ -328,7 +328,7 @@ impl FileFetcher {
   /// Fetch cached remote file.
   ///
   /// This is a recursive operation if source file has redirections.
-  fn fetch_cached(
+  pub(crate) fn fetch_cached(
     &self,
     specifier: &ModuleSpecifier,
     redirect_limit: i64,
diff --git a/cli/tests/integration/coverage_tests.rs b/cli/tests/integration/coverage_tests.rs
index feba0769e..637185e29 100644
--- a/cli/tests/integration/coverage_tests.rs
+++ b/cli/tests/integration/coverage_tests.rs
@@ -20,9 +20,11 @@ fn final_blankline() {
 }
 
 fn run_coverage_text(test_name: &str, extension: &str) {
+  let deno_dir = TempDir::new().expect("tempdir fail");
   let tempdir = TempDir::new().expect("tempdir fail");
   let tempdir = tempdir.path().join("cov");
-  let status = util::deno_cmd()
+
+  let status = util::deno_cmd_with_deno_dir(deno_dir.path())
     .current_dir(util::testdata_path())
     .arg("test")
     .arg("--quiet")
@@ -36,17 +38,19 @@ fn run_coverage_text(test_name: &str, extension: &str) {
 
   assert!(status.success());
 
-  let output = util::deno_cmd()
+  let output = util::deno_cmd_with_deno_dir(deno_dir.path())
     .current_dir(util::testdata_path())
     .arg("coverage")
-    .arg("--quiet")
     .arg("--unstable")
     .arg(format!("{}/", tempdir.to_str().unwrap()))
     .stdout(std::process::Stdio::piped())
-    .stderr(std::process::Stdio::inherit())
+    .stderr(std::process::Stdio::piped())
     .output()
     .expect("failed to spawn coverage reporter");
 
+  // Verify there's no "Check" being printed
+  assert!(output.stderr.is_empty());
+
   let actual =
     util::strip_ansi_codes(std::str::from_utf8(&output.stdout).unwrap())
       .to_string();
@@ -64,7 +68,7 @@ fn run_coverage_text(test_name: &str, extension: &str) {
 
   assert!(output.status.success());
 
-  let output = util::deno_cmd()
+  let output = util::deno_cmd_with_deno_dir(deno_dir.path())
     .current_dir(util::testdata_path())
     .arg("coverage")
     .arg("--quiet")
diff --git a/cli/tools/coverage.rs b/cli/tools/coverage.rs
index 888344fe1..3cec35606 100644
--- a/cli/tools/coverage.rs
+++ b/cli/tools/coverage.rs
@@ -1,7 +1,6 @@
 // Copyright 2018-2022 the Deno authors. All rights reserved. MIT license.
 
 use crate::colors;
-use crate::emit;
 use crate::flags::CoverageFlags;
 use crate::flags::Flags;
 use crate::fs_util::collect_files;
@@ -11,11 +10,12 @@ use crate::tools::fmt::format_json;
 
 use deno_ast::MediaType;
 use deno_ast::ModuleSpecifier;
+use deno_core::anyhow::anyhow;
+use deno_core::anyhow::Context;
 use deno_core::error::AnyError;
 use deno_core::serde_json;
 use deno_core::url::Url;
 use deno_core::LocalInspectorSession;
-use deno_runtime::permissions::Permissions;
 use regex::Regex;
 use serde::Deserialize;
 use serde::Serialize;
@@ -643,40 +643,69 @@ pub async fn cover_files(
   for script_coverage in script_coverages {
     let module_specifier =
       deno_core::resolve_url_or_path(&script_coverage.url)?;
-    ps.prepare_module_load(
-      vec![module_specifier.clone()],
-      false,
-      emit::TypeLib::UnstableDenoWindow,
-      Permissions::allow_all(),
-      Permissions::allow_all(),
-      false,
-    )
-    .await?;
-
-    let module_source = ps.load(module_specifier.clone(), None, false)?;
-    let script_source = &module_source.code;
 
+    let maybe_file = if module_specifier.scheme() == "file" {
+      ps.file_fetcher.get_source(&module_specifier)
+    } else {
+      ps.file_fetcher
+        .fetch_cached(&module_specifier, 10)
+        .with_context(|| {
+          format!("Failed to fetch \"{}\" from cache.", module_specifier)
+        })?
+    };
+    let file = maybe_file.ok_or_else(|| {
+      anyhow!("Failed to fetch \"{}\" from cache. 
+          Before generating coverage report, run `deno test --coverage` to ensure consistent state.", 
+          module_specifier
+        )
+    })?;
+
+    // Check if file was transpiled
+    let transpiled_source = match file.media_type {
+      MediaType::JavaScript
+      | MediaType::Unknown
+      | MediaType::Cjs
+      | MediaType::Mjs
+      | MediaType::Json => file.source.as_ref().clone(),
+      MediaType::Dts | MediaType::Dmts | MediaType::Dcts => "".to_string(),
+      MediaType::TypeScript
+      | MediaType::Jsx
+      | MediaType::Mts
+      | MediaType::Cts
+      | MediaType::Tsx => {
+        let emit_path = ps
+          .dir
+          .gen_cache
+          .get_cache_filename_with_extension(&file.specifier, "js")
+          .unwrap_or_else(|| {
+            unreachable!("Unable to get cache filename: {}", &file.specifier)
+          });
+        match ps.dir.gen_cache.get(&emit_path) {
+          Ok(b) => String::from_utf8(b).unwrap(),
+          Err(_) => {
+            return Err(anyhow!(
+              "Missing transpiled source code for: \"{}\".
+              Before generating coverage report, run `deno test --coverage` to ensure consistent state.",
+              file.specifier,
+            ))
+          }
+        }
+      }
+      MediaType::Wasm | MediaType::TsBuildInfo | MediaType::SourceMap => {
+        unreachable!()
+      }
+    };
+
+    let original_source = &file.source;
     let maybe_source_map = ps.get_source_map(&script_coverage.url);
-    let maybe_cached_source = ps
-      .file_fetcher
-      .get_source(&module_specifier)
-      .map(|f| f.source);
 
     let coverage_report = generate_coverage_report(
       &script_coverage,
-      script_source,
+      &transpiled_source,
       &maybe_source_map,
     );
 
-    let file_text = if let Some(original_source) =
-      maybe_source_map.and(maybe_cached_source.as_ref())
-    {
-      original_source.as_str()
-    } else {
-      script_source
-    };
-
-    reporter.report(&coverage_report, file_text);
+    reporter.report(&coverage_report, original_source);
   }
 
   reporter.done();