From 7396cc51d38e18b81f44019cd404739cb1cfc933 Mon Sep 17 00:00:00 2001
From: AriPerkkio <ari.perkkio@gmail.com>
Date: Sat, 23 Mar 2024 10:11:24 +0200
Subject: [PATCH] feat: exclude lines that are missing from source maps

---
 lib/source.js                                 |  30 +-
 lib/v8-to-istanbul.js                         |   8 +-
 tap-snapshots/test/v8-to-istanbul.js.test.cjs | 462 ------------------
 3 files changed, 29 insertions(+), 471 deletions(-)

diff --git a/lib/source.js b/lib/source.js
index d8ebc215..c9b0bf48 100644
--- a/lib/source.js
+++ b/lib/source.js
@@ -1,23 +1,31 @@
 const CovLine = require('./line')
 const { sliceRange } = require('./range')
-const { originalPositionFor, generatedPositionFor, GREATEST_LOWER_BOUND, LEAST_UPPER_BOUND } = require('@jridgewell/trace-mapping')
+const { originalPositionFor, generatedPositionFor, eachMapping, GREATEST_LOWER_BOUND, LEAST_UPPER_BOUND } = require('@jridgewell/trace-mapping')
 
 module.exports = class CovSource {
-  constructor (sourceRaw, wrapperLength) {
+  constructor (sourceRaw, wrapperLength, traceMap) {
     sourceRaw = sourceRaw ? sourceRaw.trimEnd() : ''
     this.lines = []
     this.eof = sourceRaw.length
     this.shebangLength = getShebangLength(sourceRaw)
     this.wrapperLength = wrapperLength - this.shebangLength
-    this._buildLines(sourceRaw)
+    this._buildLines(sourceRaw, traceMap)
   }
 
-  _buildLines (source) {
+  _buildLines (source, traceMap) {
     let position = 0
     let ignoreCount = 0
     let ignoreAll = false
+    const linesToCover = traceMap && this._parseLinesToCover(traceMap)
+
     for (const [i, lineStr] of source.split(/(?<=\r?\n)/u).entries()) {
-      const line = new CovLine(i + 1, position, lineStr)
+      const lineNumber = i + 1
+      const line = new CovLine(lineNumber, position, lineStr)
+
+      if (linesToCover && !linesToCover.has(lineNumber)) {
+        line.ignore = true
+      }
+
       if (ignoreCount > 0) {
         line.ignore = true
         ignoreCount--
@@ -125,6 +133,18 @@ module.exports = class CovSource {
     if (this.lines[line - 1] === undefined) return this.eof
     return Math.min(this.lines[line - 1].startCol + relCol, this.lines[line - 1].endCol)
   }
+
+  _parseLinesToCover (traceMap) {
+    const linesToCover = new Set()
+
+    eachMapping(traceMap, (mapping) => {
+      if (mapping.originalLine !== null) {
+        linesToCover.add(mapping.originalLine)
+      }
+    })
+
+    return linesToCover
+  }
 }
 
 // this implementation is pulled over from istanbul-lib-sourcemap:
diff --git a/lib/v8-to-istanbul.js b/lib/v8-to-istanbul.js
index 38e6a124..d77d11be 100644
--- a/lib/v8-to-istanbul.js
+++ b/lib/v8-to-istanbul.js
@@ -58,8 +58,8 @@ module.exports = class V8ToIstanbul {
         if (!this.sourceMap.sourcesContent) {
           this.sourceMap.sourcesContent = await this.sourcesContentFromSources()
         }
-        this.covSources = this.sourceMap.sourcesContent.map((rawSource, i) => ({ source: new CovSource(rawSource, this.wrapperLength), path: this.sourceMap.sources[i] }))
-        this.sourceTranspiled = new CovSource(rawSource, this.wrapperLength)
+        this.covSources = this.sourceMap.sourcesContent.map((rawSource, i) => ({ source: new CovSource(rawSource, this.wrapperLength, this.sourceMap), path: this.sourceMap.sources[i] }))
+        this.sourceTranspiled = new CovSource(rawSource, this.wrapperLength, this.sourceMap)
       } else {
         const candidatePath = this.rawSourceMap.sourcemap.sources.length >= 1 ? this.rawSourceMap.sourcemap.sources[0] : this.rawSourceMap.sourcemap.file
         this.path = this._resolveSource(this.rawSourceMap, candidatePath || this.path)
@@ -82,8 +82,8 @@ module.exports = class V8ToIstanbul {
           // We fallback to reading the original source from disk.
           originalRawSource = await readFile(this.path, 'utf8')
         }
-        this.covSources = [{ source: new CovSource(originalRawSource, this.wrapperLength), path: this.path }]
-        this.sourceTranspiled = new CovSource(rawSource, this.wrapperLength)
+        this.covSources = [{ source: new CovSource(originalRawSource, this.wrapperLength, this.sourceMap), path: this.path }]
+        this.sourceTranspiled = new CovSource(rawSource, this.wrapperLength, this.sourceMap)
       }
     } else {
       this.covSources = [{ source: new CovSource(rawSource, this.wrapperLength), path: this.path }]
diff --git a/tap-snapshots/test/v8-to-istanbul.js.test.cjs b/tap-snapshots/test/v8-to-istanbul.js.test.cjs
index 640d6f4d..f50ebbec 100644
--- a/tap-snapshots/test/v8-to-istanbul.js.test.cjs
+++ b/tap-snapshots/test/v8-to-istanbul.js.test.cjs
@@ -2316,28 +2316,22 @@ Object {
     "13": 1,
     "14": 0,
     "15": 0,
-    "16": 0,
     "17": 0,
     "18": 1,
     "19": 1,
-    "2": 1,
     "20": 1,
     "21": 1,
     "22": 1,
     "23": 1,
     "24": 1,
-    "25": 1,
     "26": 1,
-    "27": 1,
     "28": 0,
     "29": 1,
     "3": 1,
     "30": 1,
     "4": 1,
-    "5": 1,
     "6": 1,
     "7": 1,
-    "8": 1,
     "9": 1,
   },
   "statementMap": Object {
@@ -2421,16 +2415,6 @@ Object {
         "line": 16,
       },
     },
-    "16": Object {
-      "end": Object {
-        "column": 0,
-        "line": 17,
-      },
-      "start": Object {
-        "column": 0,
-        "line": 17,
-      },
-    },
     "17": Object {
       "end": Object {
         "column": 28,
@@ -2461,16 +2445,6 @@ Object {
         "line": 20,
       },
     },
-    "2": Object {
-      "end": Object {
-        "column": 0,
-        "line": 3,
-      },
-      "start": Object {
-        "column": 0,
-        "line": 3,
-      },
-    },
     "20": Object {
       "end": Object {
         "column": 23,
@@ -2521,16 +2495,6 @@ Object {
         "line": 25,
       },
     },
-    "25": Object {
-      "end": Object {
-        "column": 0,
-        "line": 26,
-      },
-      "start": Object {
-        "column": 0,
-        "line": 26,
-      },
-    },
     "26": Object {
       "end": Object {
         "column": 3,
@@ -2541,16 +2505,6 @@ Object {
         "line": 27,
       },
     },
-    "27": Object {
-      "end": Object {
-        "column": 0,
-        "line": 28,
-      },
-      "start": Object {
-        "column": 0,
-        "line": 28,
-      },
-    },
     "28": Object {
       "end": Object {
         "column": 46,
@@ -2601,16 +2555,6 @@ Object {
         "line": 5,
       },
     },
-    "5": Object {
-      "end": Object {
-        "column": 0,
-        "line": 6,
-      },
-      "start": Object {
-        "column": 0,
-        "line": 6,
-      },
-    },
     "6": Object {
       "end": Object {
         "column": 18,
@@ -2631,16 +2575,6 @@ Object {
         "line": 8,
       },
     },
-    "8": Object {
-      "end": Object {
-        "column": 0,
-        "line": 9,
-      },
-      "start": Object {
-        "column": 0,
-        "line": 9,
-      },
-    },
     "9": Object {
       "end": Object {
         "column": 16,
@@ -2898,54 +2832,30 @@ Object {
   "s": Object {
     "0": 1,
     "1": 1,
-    "10": 1,
     "11": 1,
     "12": 1,
     "13": 1,
     "14": 1,
-    "15": 1,
     "16": 1,
     "17": 1,
     "18": 1,
-    "19": 1,
     "2": 1,
     "20": 1,
     "21": 1,
-    "22": 1,
-    "23": 1,
     "24": 1,
     "25": 0,
-    "26": 1,
-    "27": 1,
-    "28": 1,
     "29": 1,
     "3": 1,
-    "30": 1,
-    "31": 1,
     "32": 1,
-    "33": 1,
-    "34": 1,
     "35": 1,
     "36": 0,
     "37": 0,
-    "38": 1,
-    "39": 1,
     "4": 1,
-    "40": 1,
-    "41": 1,
     "42": 1,
     "43": 0,
     "44": 0,
-    "45": 0,
     "46": 0,
-    "47": 1,
-    "48": 1,
-    "49": 1,
     "5": 1,
-    "50": 1,
-    "51": 1,
-    "52": 1,
-    "53": 1,
     "54": 1,
     "55": 0,
     "56": 0,
@@ -2956,9 +2866,6 @@ Object {
     "60": 0,
     "61": 0,
     "62": 0,
-    "63": 1,
-    "64": 1,
-    "65": 1,
     "66": 1,
     "67": 0,
     "68": 0,
@@ -2966,19 +2873,10 @@ Object {
     "7": 1,
     "70": 0,
     "71": 0,
-    "72": 1,
-    "73": 1,
-    "74": 1,
     "75": 1,
-    "76": 1,
-    "77": 1,
     "78": 1,
-    "79": 1,
     "8": 1,
-    "80": 1,
-    "81": 1,
     "82": 1,
-    "9": 1,
   },
   "statementMap": Object {
     "0": Object {
@@ -3001,16 +2899,6 @@ Object {
         "line": 2,
       },
     },
-    "10": Object {
-      "end": Object {
-        "column": 53,
-        "line": 11,
-      },
-      "start": Object {
-        "column": 0,
-        "line": 11,
-      },
-    },
     "11": Object {
       "end": Object {
         "column": 46,
@@ -3051,16 +2939,6 @@ Object {
         "line": 15,
       },
     },
-    "15": Object {
-      "end": Object {
-        "column": 5,
-        "line": 16,
-      },
-      "start": Object {
-        "column": 0,
-        "line": 16,
-      },
-    },
     "16": Object {
       "end": Object {
         "column": 0,
@@ -3091,16 +2969,6 @@ Object {
         "line": 19,
       },
     },
-    "19": Object {
-      "end": Object {
-        "column": 0,
-        "line": 20,
-      },
-      "start": Object {
-        "column": 0,
-        "line": 20,
-      },
-    },
     "2": Object {
       "end": Object {
         "column": 0,
@@ -3131,26 +2999,6 @@ Object {
         "line": 22,
       },
     },
-    "22": Object {
-      "end": Object {
-        "column": 0,
-        "line": 23,
-      },
-      "start": Object {
-        "column": 0,
-        "line": 23,
-      },
-    },
-    "23": Object {
-      "end": Object {
-        "column": 38,
-        "line": 24,
-      },
-      "start": Object {
-        "column": 0,
-        "line": 24,
-      },
-    },
     "24": Object {
       "end": Object {
         "column": 25,
@@ -3171,36 +3019,6 @@ Object {
         "line": 26,
       },
     },
-    "26": Object {
-      "end": Object {
-        "column": 0,
-        "line": 27,
-      },
-      "start": Object {
-        "column": 0,
-        "line": 27,
-      },
-    },
-    "27": Object {
-      "end": Object {
-        "column": 0,
-        "line": 28,
-      },
-      "start": Object {
-        "column": 0,
-        "line": 28,
-      },
-    },
-    "28": Object {
-      "end": Object {
-        "column": 52,
-        "line": 29,
-      },
-      "start": Object {
-        "column": 0,
-        "line": 29,
-      },
-    },
     "29": Object {
       "end": Object {
         "column": 34,
@@ -3221,26 +3039,6 @@ Object {
         "line": 4,
       },
     },
-    "30": Object {
-      "end": Object {
-        "column": 0,
-        "line": 31,
-      },
-      "start": Object {
-        "column": 0,
-        "line": 31,
-      },
-    },
-    "31": Object {
-      "end": Object {
-        "column": 28,
-        "line": 32,
-      },
-      "start": Object {
-        "column": 0,
-        "line": 32,
-      },
-    },
     "32": Object {
       "end": Object {
         "column": 43,
@@ -3251,26 +3049,6 @@ Object {
         "line": 33,
       },
     },
-    "33": Object {
-      "end": Object {
-        "column": 0,
-        "line": 34,
-      },
-      "start": Object {
-        "column": 0,
-        "line": 34,
-      },
-    },
-    "34": Object {
-      "end": Object {
-        "column": 47,
-        "line": 35,
-      },
-      "start": Object {
-        "column": 0,
-        "line": 35,
-      },
-    },
     "35": Object {
       "end": Object {
         "column": 59,
@@ -3301,26 +3079,6 @@ Object {
         "line": 38,
       },
     },
-    "38": Object {
-      "end": Object {
-        "column": 4,
-        "line": 39,
-      },
-      "start": Object {
-        "column": 0,
-        "line": 39,
-      },
-    },
-    "39": Object {
-      "end": Object {
-        "column": 4,
-        "line": 40,
-      },
-      "start": Object {
-        "column": 0,
-        "line": 40,
-      },
-    },
     "4": Object {
       "end": Object {
         "column": 42,
@@ -3331,26 +3089,6 @@ Object {
         "line": 5,
       },
     },
-    "40": Object {
-      "end": Object {
-        "column": 0,
-        "line": 41,
-      },
-      "start": Object {
-        "column": 0,
-        "line": 41,
-      },
-    },
-    "41": Object {
-      "end": Object {
-        "column": 33,
-        "line": 42,
-      },
-      "start": Object {
-        "column": 0,
-        "line": 42,
-      },
-    },
     "42": Object {
       "end": Object {
         "column": 45,
@@ -3381,16 +3119,6 @@ Object {
         "line": 45,
       },
     },
-    "45": Object {
-      "end": Object {
-        "column": 4,
-        "line": 46,
-      },
-      "start": Object {
-        "column": 0,
-        "line": 46,
-      },
-    },
     "46": Object {
       "end": Object {
         "column": 65,
@@ -3401,36 +3129,6 @@ Object {
         "line": 47,
       },
     },
-    "47": Object {
-      "end": Object {
-        "column": 4,
-        "line": 48,
-      },
-      "start": Object {
-        "column": 0,
-        "line": 48,
-      },
-    },
-    "48": Object {
-      "end": Object {
-        "column": 0,
-        "line": 49,
-      },
-      "start": Object {
-        "column": 0,
-        "line": 49,
-      },
-    },
-    "49": Object {
-      "end": Object {
-        "column": 35,
-        "line": 50,
-      },
-      "start": Object {
-        "column": 0,
-        "line": 50,
-      },
-    },
     "5": Object {
       "end": Object {
         "column": 0,
@@ -3441,46 +3139,6 @@ Object {
         "line": 6,
       },
     },
-    "50": Object {
-      "end": Object {
-        "column": 47,
-        "line": 51,
-      },
-      "start": Object {
-        "column": 0,
-        "line": 51,
-      },
-    },
-    "51": Object {
-      "end": Object {
-        "column": 56,
-        "line": 52,
-      },
-      "start": Object {
-        "column": 0,
-        "line": 52,
-      },
-    },
-    "52": Object {
-      "end": Object {
-        "column": 50,
-        "line": 53,
-      },
-      "start": Object {
-        "column": 0,
-        "line": 53,
-      },
-    },
-    "53": Object {
-      "end": Object {
-        "column": 36,
-        "line": 54,
-      },
-      "start": Object {
-        "column": 0,
-        "line": 54,
-      },
-    },
     "54": Object {
       "end": Object {
         "column": 49,
@@ -3581,36 +3239,6 @@ Object {
         "line": 63,
       },
     },
-    "63": Object {
-      "end": Object {
-        "column": 4,
-        "line": 64,
-      },
-      "start": Object {
-        "column": 0,
-        "line": 64,
-      },
-    },
-    "64": Object {
-      "end": Object {
-        "column": 0,
-        "line": 65,
-      },
-      "start": Object {
-        "column": 0,
-        "line": 65,
-      },
-    },
-    "65": Object {
-      "end": Object {
-        "column": 73,
-        "line": 66,
-      },
-      "start": Object {
-        "column": 0,
-        "line": 66,
-      },
-    },
     "66": Object {
       "end": Object {
         "column": 44,
@@ -3681,36 +3309,6 @@ Object {
         "line": 72,
       },
     },
-    "72": Object {
-      "end": Object {
-        "column": 4,
-        "line": 73,
-      },
-      "start": Object {
-        "column": 0,
-        "line": 73,
-      },
-    },
-    "73": Object {
-      "end": Object {
-        "column": 0,
-        "line": 74,
-      },
-      "start": Object {
-        "column": 0,
-        "line": 74,
-      },
-    },
-    "74": Object {
-      "end": Object {
-        "column": 41,
-        "line": 75,
-      },
-      "start": Object {
-        "column": 0,
-        "line": 75,
-      },
-    },
     "75": Object {
       "end": Object {
         "column": 120,
@@ -3721,26 +3319,6 @@ Object {
         "line": 76,
       },
     },
-    "76": Object {
-      "end": Object {
-        "column": 0,
-        "line": 77,
-      },
-      "start": Object {
-        "column": 0,
-        "line": 77,
-      },
-    },
-    "77": Object {
-      "end": Object {
-        "column": 28,
-        "line": 78,
-      },
-      "start": Object {
-        "column": 0,
-        "line": 78,
-      },
-    },
     "78": Object {
       "end": Object {
         "column": 29,
@@ -3751,16 +3329,6 @@ Object {
         "line": 79,
       },
     },
-    "79": Object {
-      "end": Object {
-        "column": 0,
-        "line": 80,
-      },
-      "start": Object {
-        "column": 0,
-        "line": 80,
-      },
-    },
     "8": Object {
       "end": Object {
         "column": 46,
@@ -3771,26 +3339,6 @@ Object {
         "line": 9,
       },
     },
-    "80": Object {
-      "end": Object {
-        "column": 0,
-        "line": 81,
-      },
-      "start": Object {
-        "column": 0,
-        "line": 81,
-      },
-    },
-    "81": Object {
-      "end": Object {
-        "column": 41,
-        "line": 82,
-      },
-      "start": Object {
-        "column": 0,
-        "line": 82,
-      },
-    },
     "82": Object {
       "end": Object {
         "column": 56,
@@ -3801,16 +3349,6 @@ Object {
         "line": 83,
       },
     },
-    "9": Object {
-      "end": Object {
-        "column": 4,
-        "line": 10,
-      },
-      "start": Object {
-        "column": 0,
-        "line": 10,
-      },
-    },
   },
 }
 `