fix(coverage): use source maps when printing pretty reports (#9278)

This commits makes use of source maps and the original source 
when printing lacking line coverage in the pretty printer.

Only the executable lines are checked as before (as non-executable 
lines will always be ignored anyways). The lines then mapped to the 
appropriate source line when a source map is present.

cli/tests/test_branch_coverage.out

@@ -5,6 +5,6 @@ test branch ... ok ([WILDCARD])
 test result: ok. 1 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out ([WILDCARD])
 
 cover [WILDCARD]/tests/subdir/branch.ts ... 66.667% (6/9)
-   5 |     else {
-   6 |         return false;
-   7 |     }
+   4 |   } else {
+   5 |     return false;
+   6 |   }

cli/tests/test_coverage.out

@@ -4,22 +4,23 @@ test returnsFooSuccess ... ok ([WILDCARD])
 
 test result: ok. 1 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out ([WILDCARD])
 
-cover [WILDCARD]/cli/tests/subdir/mod1.ts ... 35.714% (5/14)
-   2 | export function returnsHi() {
-   3 |     return "Hi";
-   4 | }
+cover [WILDCARD]/tests/subdir/mod1.ts ... 35.714% (5/14)
+   3 | export function returnsHi(): string {
+   4 |   return "Hi";
+   5 | }
 -----|-----
-   8 | export function printHello3() {
-   9 |     printHello2();
-  10 | }
-  11 | export function throwsError() {
-  12 |     throw Error("exception from mod1");
+  11 | export function printHello3(): void {
+  12 |   printHello2();
   13 | }
-cover [WILDCARD]/cli/tests/subdir/print_hello.ts ... 25.000% (1/4)
-   1 | export function printHello() {
+-----|-----
+  15 | export function throwsError(): void {
+  16 |   throw Error("exception from mod1");
+  17 | }
+cover [WILDCARD]/tests/subdir/print_hello.ts ... 25.000% (1/4)
+   1 | export function printHello(): void {
    2 |   console.log("Hello");
    3 | }
-cover [WILDCARD]/cli/tests/subdir/subdir2/mod2.ts ... 62.500% (5/8)
-   5 | export function printHello2() {
-   6 |     printHello();
-   7 | }
+cover [WILDCARD]/tests/subdir/subdir2/mod2.ts ... 62.500% (5/8)
+   7 | export function printHello2(): void {
+   8 |   printHello();
+   9 | }

cli/tests/test_run_combined_coverage.out

@@ -14,18 +14,19 @@ test result: ok. 2 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out ([WIL
 
 cover [WILDCARD]/tests/run_coverage.ts ... 100.000% (3/3)
 cover [WILDCARD]/tests/subdir/mod1.ts ... 57.143% (8/14)
-   8 | export function printHello3() {
-   9 |     printHello2();
-  10 | }
-  11 | export function throwsError() {
-  12 |     throw Error("exception from mod1");
+  11 | export function printHello3(): void {
+  12 |   printHello2();
   13 | }
+-----|-----
+  15 | export function throwsError(): void {
+  16 |   throw Error("exception from mod1");
+  17 | }
 cover [WILDCARD]/tests/subdir/print_hello.ts ... 25.000% (1/4)
-   1 | export function printHello() {
+   1 | export function printHello(): void {
    2 |   console.log("Hello");
    3 | }
 cover [WILDCARD]/tests/subdir/subdir2/mod2.ts ... 62.500% (5/8)
-   5 | export function printHello2() {
-   6 |     printHello();
-   7 | }
+   7 | export function printHello2(): void {
+   8 |   printHello();
+   9 | }
 cover [WILDCARD]/tests/test_coverage.ts ... 100.000% (5/5)

cli/tests/test_run_run_coverage.out

@@ -7,23 +7,26 @@ test result: ok. 1 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out ([WIL
 
 cover [WILDCARD]/tests/run_coverage.ts ... 100.000% (3/3)
 cover [WILDCARD]/tests/subdir/mod1.ts ... 35.714% (5/14)
-   5 | export function returnsFoo2() {
-   6 |     return returnsFoo();
-   7 | }
-   8 | export function printHello3() {
-   9 |     printHello2();
-  10 | }
-  11 | export function throwsError() {
-  12 |     throw Error("exception from mod1");
+   7 | export function returnsFoo2(): string {
+   8 |   return returnsFoo();
+   9 | }
+-----|-----
+  11 | export function printHello3(): void {
+  12 |   printHello2();
   13 | }
+-----|-----
+  15 | export function throwsError(): void {
+  16 |   throw Error("exception from mod1");
+  17 | }
 cover [WILDCARD]/tests/subdir/print_hello.ts ... 25.000% (1/4)
-   1 | export function printHello() {
+   1 | export function printHello(): void {
    2 |   console.log("Hello");
    3 | }
 cover [WILDCARD]/tests/subdir/subdir2/mod2.ts ... 25.000% (2/8)
-   2 | export function returnsFoo() {
-   3 |     return "Foo";
-   4 | }
-   5 | export function printHello2() {
-   6 |     printHello();
-   7 | }
+   3 | export function returnsFoo(): string {
+   4 |   return "Foo";
+   5 | }
+-----|-----
+   7 | export function printHello2(): void {
+   8 |   printHello();
+   9 | }

cli/tests/test_run_test_coverage.out

@@ -1,6 +1,6 @@
-Check [WILDCARD]/$deno$test.ts
+Check [WILDCARD]/tests/$deno$test.ts
 running 1 tests
-test spawn test ... Check [WILDCARD]/$deno$test.ts
+test spawn test ... Check [WILDCARD]/tests/$deno$test.ts
 running 1 tests
 test returnsFooSuccess ... ok ([WILDCARD])
 
@@ -10,23 +10,24 @@ ok ([WILDCARD])
 
 test result: ok. 1 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out ([WILDCARD])
 
-cover [WILDCARD]/subdir/mod1.ts ... 35.714% (5/14)
-   2 | export function returnsHi() {
-   3 |     return "Hi";
-   4 | }
+cover [WILDCARD]/tests/subdir/mod1.ts ... 35.714% (5/14)
+   3 | export function returnsHi(): string {
+   4 |   return "Hi";
+   5 | }
 -----|-----
-   8 | export function printHello3() {
-   9 |     printHello2();
-  10 | }
-  11 | export function throwsError() {
-  12 |     throw Error("exception from mod1");
+  11 | export function printHello3(): void {
+  12 |   printHello2();
   13 | }
-cover [WILDCARD]/subdir/print_hello.ts ... 25.000% (1/4)
-   1 | export function printHello() {
+-----|-----
+  15 | export function throwsError(): void {
+  16 |   throw Error("exception from mod1");
+  17 | }
+cover [WILDCARD]/tests/subdir/print_hello.ts ... 25.000% (1/4)
+   1 | export function printHello(): void {
    2 |   console.log("Hello");
    3 | }
-cover [WILDCARD]/subdir/subdir2/mod2.ts ... 62.500% (5/8)
-   5 | export function printHello2() {
-   6 |     printHello();
-   7 | }
-cover [WILDCARD]/test_coverage.ts ... 100.000% (5/5)
+cover [WILDCARD]/tests/subdir/subdir2/mod2.ts ... 62.500% (5/8)
+   7 | export function printHello2(): void {
+   8 |   printHello();
+   9 | }
+cover [WILDCARD]/tests/test_coverage.ts ... 100.000% (5/5)

cli/tools/coverage.rs

@@ -6,6 +6,7 @@ use crate::colors;
 use crate::media_type::MediaType;
 use crate::module_graph::TypeLib;
 use crate::program_state::ProgramState;
+use crate::source_maps::SourceMapGetter;
 use deno_core::error::AnyError;
 use deno_core::serde_json;
 use deno_core::serde_json::json;
@@ -15,6 +16,7 @@ use deno_runtime::inspector::InspectorSession;
 use deno_runtime::permissions::Permissions;
 use serde::Deserialize;
 use serde::Serialize;
+use sourcemap::SourceMap;
 use std::fs;
 use std::path::PathBuf;
 use std::sync::Arc;
@@ -130,7 +132,15 @@ impl PrettyCoverageReporter {
     &mut self,
     script_coverage: &ScriptCoverage,
     script_source: &str,
+    maybe_source_map: Option<Vec<u8>>,
+    maybe_original_source: Option<String>,
   ) {
+    let maybe_source_map = if let Some(source_map) = maybe_source_map {
+      Some(SourceMap::from_slice(&source_map).unwrap())
+    } else {
+      None
+    };
+
     let mut ignored_spans: Vec<Span> = Vec::new();
     for item in ast::lex("", script_source, &MediaType::JavaScript) {
       if let TokenOrComment::Token(_) = item.inner {
@@ -221,8 +231,39 @@ impl PrettyCoverageReporter {
         println!("{}", colors::red(&line_coverage));
       }
 
+      let output_lines =
+        if let Some(original_source) = maybe_original_source.as_ref() {
+          original_source.split('\n').collect::<Vec<_>>()
+        } else {
+          lines
+        };
+
+      let output_indices = if let Some(source_map) = maybe_source_map.as_ref() {
+        // The compiled executable source lines have to be mapped to all the original source lines that they
+        // came from; this happens in a couple of emit scenarios, the most common example being function
+        // declarations where the compiled JavaScript code only takes a line but the original
+        // TypeScript source spans 10 lines.
+        let mut indices = uncovered_lines
+          .iter()
+          .map(|i| {
+            source_map
+              .tokens()
+              .filter(move |token| token.get_dst_line() as usize == *i)
+              .map(|token| token.get_src_line() as usize)
+          })
+          .flatten()
+          .collect::<Vec<usize>>();
+
+        indices.sort_unstable();
+        indices.dedup();
+
+        indices
+      } else {
+        uncovered_lines
+      };
+
       let mut last_line = None;
-      for line_index in uncovered_lines {
+      for line_index in output_indices {
         const WIDTH: usize = 4;
         const SEPERATOR: &str = "|";
 
@@ -238,7 +279,7 @@ impl PrettyCoverageReporter {
           "{:width$} {} {}",
           line_index + 1,
           colors::gray(SEPERATOR),
-          colors::red(&lines[line_index]),
+          colors::red(&output_lines[line_index]),
           width = WIDTH
         );
 
@@ -354,7 +395,18 @@ pub async fn report_coverages(
     let module_source = program_state.load(module_specifier.clone(), None)?;
     let script_source = &module_source.code;
 
-    coverage_reporter.visit_coverage(&script_coverage, &script_source);
+    let maybe_source_map = program_state.get_source_map(&script_coverage.url);
+    let maybe_cached_source = program_state
+      .file_fetcher
+      .get_source(&module_specifier)
+      .map(|f| f.source);
+
+    coverage_reporter.visit_coverage(
+      &script_coverage,
+      &script_source,
+      maybe_source_map,
+      maybe_cached_source,
+    );
   }
 
   Ok(())