feat: write eresolve error files to the logs directorylk/timing-file

Also refactor all files written to the logs directory to use the same
code path for file name creation.

16 files changed, 194 insertions, 234 deletions

diff --git a/lib/npm.js b/lib/npm.js
index a178dca72..4198ed905 100644
--- a/lib/npm.js
+++ b/lib/npm.js
@@ -18,11 +18,9 @@ const replaceInfo = require('./utils/replace-info.js')
 const updateNotifier = require('./utils/update-notifier.js')
 const pkg = require('../package.json')
 const cmdList = require('./utils/cmd-list.js')
-const runId = require('./utils/run-id.js')
 
 let warnedNonDashArg = false
 const _load = Symbol('_load')
-const RUN_ID = runId()
 
 class Npm extends EventEmitter {
   static get version () {
@@ -34,16 +32,16 @@ class Npm extends EventEmitter {
   loadErr = null
   argv = []
 
+  #runId = new Date().toISOString().replace(/[.:]/g, '_')
   #loadPromise = null
   #tmpFolder = null
   #title = 'npm'
   #argvClean = []
   #chalk = null
 
-  #logFile = new LogFile({ id: RUN_ID })
+  #logFile = new LogFile()
   #display = new Display()
   #timers = new Timers({
-    id: RUN_ID,
     start: 'npm',
     listener: (name, ms) => {
       const args = ['timing', name, `Completed in ${ms}ms`]
@@ -209,6 +207,7 @@ class Npm extends EventEmitter {
 
   writeTimingFile () {
     this.#timers.writeFile({
+      id: this.#runId,
       command: this.#argvClean,
       logfiles: this.logFiles,
       version: this.version,
@@ -289,7 +288,7 @@ class Npm extends EventEmitter {
 
     this.time('npm:load:logFile', () => {
       this.#logFile.load({
-        dir: this.logsDir,
+        path: this.logPath,
         logsMax: this.config.get('logs-max'),
       })
       log.verbose('logfile', this.#logFile.files[0] || 'no logfile created')
@@ -297,7 +296,7 @@ class Npm extends EventEmitter {
 
     this.time('npm:load:timers', () =>
       this.#timers.load({
-        dir: this.config.get('timing') ? this.logsDir : null,
+        path: this.config.get('timing') ? this.logPath : null,
       })
     )
 
@@ -371,6 +370,10 @@ class Npm extends EventEmitter {
     return this.config.get('logs-dir') || join(this.cache, '_logs')
   }
 
+  logPath = (file = '') => {
+    return resolve(this.logsDir, `${this.#runId}-${file}`)
+  }
+
   get timingFile () {
     return this.#timers.file
   }
diff --git a/lib/utils/error-message.js b/lib/utils/error-message.js
index adf10a56f..aee376120 100644
--- a/lib/utils/error-message.js
+++ b/lib/utils/error-message.js
@@ -8,6 +8,7 @@ const log = require('./log-shim')
 module.exports = (er, npm) => {
   const short = []
   const detail = []
+  const files = []
 
   if (er.message) {
     er.message = replaceInfo(er.message)
@@ -17,14 +18,17 @@ module.exports = (er, npm) => {
   }
 
   switch (er.code) {
-    case 'ERESOLVE':
+    case 'ERESOLVE': {
       short.push(['ERESOLVE', er.message])
       detail.push(['', ''])
       // XXX(display): error messages are logged so we use the logColor since that is based
       // on stderr. This should be handled solely by the display layer so it could also be
       // printed to stdout if necessary.
-      detail.push(['', report(er, !!npm.logColor, resolve(npm.cache, 'eresolve-report.txt'))])
+      const { explanation, file } = report(er, !!npm.logColor)
+      detail.push(['', explanation])
+      files.push(['eresolve-report.txt', file])
       break
+    }
 
     case 'ENOLOCK': {
       const cmd = npm.command || ''
@@ -398,5 +402,5 @@ module.exports = (er, npm) => {
 
       break
   }
-  return { summary: short, detail: detail }
+  return { summary: short, detail, files }
 }
diff --git a/lib/utils/exit-handler.js b/lib/utils/exit-handler.js
index d8ae9994d..19bbba240 100644
--- a/lib/utils/exit-handler.js
+++ b/lib/utils/exit-handler.js
@@ -1,4 +1,5 @@
 const os = require('os')
+const fs = require('@npmcli/fs')
 
 const log = require('./log-shim.js')
 const errorMessage = require('./error-message.js')
@@ -18,11 +19,10 @@ process.on('exit', code => {
   // unfinished timer check below
   process.emit('timeEnd', 'npm')
 
-  const hasNpm = !!npm
-  const hasLoadedNpm = hasNpm && npm.config.loaded
+  const hasLoadedNpm = npm?.config.loaded
 
   // Unfinished timers can be read before config load
-  if (hasNpm) {
+  if (npm) {
     for (const [name, timer] of npm.unfinishedTimers) {
       log.verbose('unfinished npm timer', name, timer)
     }
@@ -111,10 +111,9 @@ const exitHandler = err => {
 
   log.disableProgress()
 
-  const hasNpm = !!npm
-  const hasLoadedNpm = hasNpm && npm.config.loaded
+  const hasLoadedNpm = npm?.config.loaded
 
-  if (!hasNpm) {
+  if (!npm) {
     err = err || new Error('Exit prior to setting npm in exit handler')
     // eslint-disable-next-line no-console
     console.error(err.stack || err.message)
@@ -181,8 +180,24 @@ const exitHandler = err => {
         }
       }
 
-      const msg = errorMessage(err, npm)
-      for (const errline of [...msg.summary, ...msg.detail]) {
+      const { summary, detail, files = [] } = errorMessage(err, npm)
+
+      for (let [file, content] of files) {
+        file = npm.logPath(file)
+        content = `'Log files:\n${npm.logFiles.join('\n')}\n\n${content.trim()}\n`
+        try {
+          fs.withOwnerSync(
+            file,
+            () => fs.writeFileSync(file, content),
+            { owner: 'inherit' }
+          )
+          detail.push(['', `\n\nFor a full report see:\n${file}`])
+        } catch (err) {
+          log.warn('', `Could not write error message to ${file} due to ${err}`)
+        }
+      }
+
+      for (const errline of [...summary, ...detail]) {
         log.error(...errline)
       }
 
@@ -190,8 +205,8 @@ const exitHandler = err => {
         const error = {
           error: {
             code: err.code,
-            summary: messageText(msg.summary),
-            detail: messageText(msg.detail),
+            summary: messageText(summary),
+            detail: messageText(detail),
           },
         }
         npm.outputError(JSON.stringify(error, null, 2))
diff --git a/lib/utils/explain-eresolve.js b/lib/utils/explain-eresolve.js
index 7f6a10869..480cd8e5c 100644
--- a/lib/utils/explain-eresolve.js
+++ b/lib/utils/explain-eresolve.js
@@ -1,7 +1,6 @@
 // this is called when an ERESOLVE error is caught in the exit-handler,
 // or when there's a log.warn('eresolve', msg, explanation), to turn it
 // into a human-intelligible explanation of what's wrong and how to fix.
-const { writeFileSync } = require('fs')
 const { explainEdge, explainNode, printNode } = require('./explain-dep.js')
 
 // expl is an explanation object that comes from Arborist.  It looks like:
@@ -45,27 +44,25 @@ const explain = (expl, color, depth) => {
 }
 
 // generate a full verbose report and tell the user how to fix it
-const report = (expl, color, fullReport) => {
-  const orNoStrict = expl.strictPeerDeps ? '--no-strict-peer-deps, ' : ''
-  const fix = `Fix the upstream dependency conflict, or retry
-this command with ${orNoStrict}--force, or --legacy-peer-deps
-to accept an incorrect (and potentially broken) dependency resolution.`
-
-  writeFileSync(fullReport, `# npm resolution error report
-
-${new Date().toISOString()}
-
-${explain(expl, false, Infinity)}
+const report = (expl, color) => {
+  const flags = [
+    expl.strictPeerDeps ? '--no-strict-peer-deps' : '',
+    '--force',
+    '--legacy-peer-deps',
+  ].filter(Boolean)
 
-${fix}
+  const or = (arr) => arr.length <= 2
+    ? arr.join(' or ') :
+    arr.map((v, i, l) => i + 1 === l.length ? `or ${v}` : v).join(', ')
 
-Raw JSON explanation object:
-
-${JSON.stringify(expl, null, 2)}
-`, 'utf8')
+  const fix = `Fix the upstream dependency conflict, or retry
+this command with ${or(flags)}
+to accept an incorrect (and potentially broken) dependency resolution.`
 
-  return explain(expl, color, 4) +
-    `\n\n${fix}\n\nSee ${fullReport} for a full report.`
+  return {
+    explanation: `${explain(expl, color, 4)}\n\n${fix}`,
+    file: `# npm resolution error report\n\n${explain(expl, false, Infinity)}\n\n${fix}`,
+  }
 }
 
 module.exports = {
diff --git a/lib/utils/log-file.js b/lib/utils/log-file.js
index a18eb2878..a10b69531 100644
--- a/lib/utils/log-file.js
+++ b/lib/utils/log-file.js
@@ -7,16 +7,11 @@ const MiniPass = require('minipass')
 const fsMiniPass = require('fs-minipass')
 const fs = require('@npmcli/fs')
 const log = require('./log-shim')
-const runId = require('./run-id')
 
 const padZero = (n, length) => n.toString().padStart(length.toString().length, '0')
 const globify = pattern => pattern.split('\\').join('/')
 
 class LogFiles {
-  // If we write multiple log files we want them all to have the same
-  // identifier for sorting and matching purposes
-  #logId = null
-
   // Default to a plain minipass stream so we can buffer
   // initial writes before we know the cache location
   #logStream = null
@@ -34,16 +29,14 @@ class LogFiles {
 
   #fileLogCount = 0
   #totalLogCount = 0
-  #dir = null
+  #path = null
   #logsMax = null
   #files = []
 
   constructor ({
-    id = runId(),
     maxLogsPerFile = 50_000,
     maxFilesPerProcess = 5,
   } = {}) {
-    this.#logId = id
     this.#MAX_LOGS_PER_FILE = maxLogsPerFile
     this.#MAX_FILES_PER_PROCESS = maxFilesPerProcess
     this.on()
@@ -73,10 +66,10 @@ class LogFiles {
     this.#endStream()
   }
 
-  load ({ dir, logsMax = Infinity } = {}) {
+  load ({ path, logsMax = Infinity } = {}) {
     // dir is user configurable and is required to exist so
     // this can error if the dir is missing or not configured correctly
-    this.#dir = dir
+    this.#path = path
     this.#logsMax = logsMax
 
     // Log stream has already ended
@@ -84,7 +77,7 @@ class LogFiles {
       return
     }
 
-    log.verbose('logfile', `logs-max:${logsMax} dir:${dir}`)
+    log.verbose('logfile', `logs-max:${logsMax} dir:${this.#path()}`)
 
     // Pipe our initial stream to our new file stream and
     // set that as the new log logstream for future writes
@@ -164,7 +157,7 @@ class LogFiles {
   }
 
   #getLogFilePath (count = '') {
-    return path.resolve(this.#dir, `${this.#logId}-debug-${count}.log`)
+    return this.#path(`debug-${count}.log`)
   }
 
   #openLogFile () {
diff --git a/lib/utils/run-id.js b/lib/utils/run-id.js
deleted file mode 100644
index b7e7cf797..000000000
--- a/lib/utils/run-id.js
+++ /dev/null
@@ -1,3 +0,0 @@
-module.exports = (d = new Date()) => {
-  return d.toISOString().replace(/[.:]/g, '_')
-}
diff --git a/lib/utils/timers.js b/lib/utils/timers.js
index d4f8d8bde..05b7f1813 100644
--- a/lib/utils/timers.js
+++ b/lib/utils/timers.js
@@ -1,8 +1,6 @@
 const EE = require('events')
-const { resolve } = require('path')
 const fs = require('@npmcli/fs')
 const log = require('./log-shim')
-const runId = require('./run-id')
 
 // This is an event emiiter but on/off
 // only listen on a single internal event that gets
@@ -10,16 +8,14 @@ const runId = require('./run-id')
 class Timers extends EE {
   file = null
 
-  #id = null
   #unfinished = new Map()
   #finished = {}
   #onTimeEnd = Symbol('onTimeEnd')
   #initialListener = null
   #initialTimer = null
 
-  constructor ({ id = runId(), listener = null, start = 'npm' } = {}) {
+  constructor ({ listener = null, start = 'npm' } = {}) {
     super()
-    this.#id = id
     this.#initialListener = listener
     this.#initialTimer = start
     this.#init()
@@ -71,9 +67,9 @@ class Timers extends EE {
     return end
   }
 
-  load ({ dir } = {}) {
-    if (dir) {
-      this.file = resolve(dir, `${this.#id}-timing.json`)
+  load ({ path } = {}) {
+    if (path) {
+      this.file = path('timing.json')
     }
   }
 
@@ -86,10 +82,7 @@ class Timers extends EE {
       const globalStart = this.started
       const globalEnd = this.#finished.npm || Date.now()
       const content = {
-        metadata: {
-          id: this.#id,
-          ...metadata,
-        },
+        metadata,
         timers: this.#finished,
         // add any unfinished timers with their relative start/end
         unfinishedTimers: [...this.#unfinished.entries()].reduce((acc, [name, start]) => {
diff --git a/tap-snapshots/test/lib/utils/error-message.js.test.cjs b/tap-snapshots/test/lib/utils/error-message.js.test.cjs
index 8e772e869..de21a46d2 100644
--- a/tap-snapshots/test/lib/utils/error-message.js.test.cjs
+++ b/tap-snapshots/test/lib/utils/error-message.js.test.cjs
@@ -509,7 +509,7 @@ Array [
   ],
   Array [
     "logfile",
-    "logs-max:10 dir:{CWD}/test/lib/utils/tap-testdir-error-message-eacces-eperm--windows-false-loaded-true-cachePath-false-cacheDest-false-/cache/_logs",
+    "logs-max:10 dir:{CWD}/test/lib/utils/tap-testdir-error-message-eacces-eperm--windows-false-loaded-true-cachePath-false-cacheDest-false-/cache/_logs/{DATE}-",
   ],
   Array [
     "logfile",
@@ -549,7 +549,7 @@ Array [
   ],
   Array [
     "logfile",
-    "logs-max:10 dir:{CWD}/test/lib/utils/tap-testdir-error-message-eacces-eperm--windows-false-loaded-true-cachePath-false-cacheDest-true-/cache/_logs",
+    "logs-max:10 dir:{CWD}/test/lib/utils/tap-testdir-error-message-eacces-eperm--windows-false-loaded-true-cachePath-false-cacheDest-true-/cache/_logs/{DATE}-",
   ],
   Array [
     "logfile",
@@ -592,7 +592,7 @@ Array [
   ],
   Array [
     "logfile",
-    "logs-max:10 dir:{CWD}/test/lib/utils/tap-testdir-error-message-eacces-eperm--windows-false-loaded-true-cachePath-true-cacheDest-false-/cache/_logs",
+    "logs-max:10 dir:{CWD}/test/lib/utils/tap-testdir-error-message-eacces-eperm--windows-false-loaded-true-cachePath-true-cacheDest-false-/cache/_logs/{DATE}-",
   ],
   Array [
     "logfile",
@@ -635,7 +635,7 @@ Array [
   ],
   Array [
     "logfile",
-    "logs-max:10 dir:{CWD}/test/lib/utils/tap-testdir-error-message-eacces-eperm--windows-false-loaded-true-cachePath-true-cacheDest-true-/cache/_logs",
+    "logs-max:10 dir:{CWD}/test/lib/utils/tap-testdir-error-message-eacces-eperm--windows-false-loaded-true-cachePath-true-cacheDest-true-/cache/_logs/{DATE}-",
   ],
   Array [
     "logfile",
@@ -825,7 +825,7 @@ Array [
   ],
   Array [
     "logfile",
-    "logs-max:10 dir:{CWD}/test/lib/utils/tap-testdir-error-message-eacces-eperm--windows-true-loaded-true-cachePath-false-cacheDest-false-/cache/_logs",
+    "logs-max:10 dir:{CWD}/test/lib/utils/tap-testdir-error-message-eacces-eperm--windows-true-loaded-true-cachePath-false-cacheDest-false-/cache/_logs/{DATE}-",
   ],
   Array [
     "logfile",
@@ -876,7 +876,7 @@ Array [
   ],
   Array [
     "logfile",
-    "logs-max:10 dir:{CWD}/test/lib/utils/tap-testdir-error-message-eacces-eperm--windows-true-loaded-true-cachePath-false-cacheDest-true-/cache/_logs",
+    "logs-max:10 dir:{CWD}/test/lib/utils/tap-testdir-error-message-eacces-eperm--windows-true-loaded-true-cachePath-false-cacheDest-true-/cache/_logs/{DATE}-",
   ],
   Array [
     "logfile",
@@ -927,7 +927,7 @@ Array [
   ],
   Array [
     "logfile",
-    "logs-max:10 dir:{CWD}/test/lib/utils/tap-testdir-error-message-eacces-eperm--windows-true-loaded-true-cachePath-true-cacheDest-false-/cache/_logs",
+    "logs-max:10 dir:{CWD}/test/lib/utils/tap-testdir-error-message-eacces-eperm--windows-true-loaded-true-cachePath-true-cacheDest-false-/cache/_logs/{DATE}-",
   ],
   Array [
     "logfile",
@@ -978,7 +978,7 @@ Array [
   ],
   Array [
     "logfile",
-    "logs-max:10 dir:{CWD}/test/lib/utils/tap-testdir-error-message-eacces-eperm--windows-true-loaded-true-cachePath-true-cacheDest-true-/cache/_logs",
+    "logs-max:10 dir:{CWD}/test/lib/utils/tap-testdir-error-message-eacces-eperm--windows-true-loaded-true-cachePath-true-cacheDest-true-/cache/_logs/{DATE}-",
   ],
   Array [
     "logfile",
@@ -1176,6 +1176,12 @@ Object {
       "explanation",
     ],
   ],
+  "files": Array [
+    Array [
+      "eresolve-report.txt",
+      "report",
+    ],
+  ],
   "summary": Array [
     Array [
       "ERESOLVE",
diff --git a/tap-snapshots/test/lib/utils/exit-handler.js.test.cjs b/tap-snapshots/test/lib/utils/exit-handler.js.test.cjs
index edb7edaa5..4d52c02d9 100644
--- a/tap-snapshots/test/lib/utils/exit-handler.js.test.cjs
+++ b/tap-snapshots/test/lib/utils/exit-handler.js.test.cjs
@@ -15,7 +15,7 @@ exports[`test/lib/utils/exit-handler.js TAP handles unknown error with logs and
 20 verbose argv
 21 timing npm:load:setTitle Completed in {TIME}ms
 23 timing npm:load:display Completed in {TIME}ms
-24 verbose logfile logs-max:10 dir:{CWD}/test/lib/utils/tap-testdir-exit-handler-handles-unknown-error-with-logs-and-debug-file/cache/_logs
+24 verbose logfile logs-max:10 dir:{CWD}/test/lib/utils/tap-testdir-exit-handler-handles-unknown-error-with-logs-and-debug-file/cache/_logs/{DATE}-
 25 verbose logfile {CWD}/test/lib/utils/tap-testdir-exit-handler-handles-unknown-error-with-logs-and-debug-file/cache/_logs/{DATE}-debug-0.log
 26 timing npm:load:logFile Completed in {TIME}ms
 27 timing npm:load:timers Completed in {TIME}ms
@@ -47,7 +47,7 @@ verbose title npm
 verbose argv 
 timing npm:load:setTitle Completed in {TIME}ms
 timing npm:load:display Completed in {TIME}ms
-verbose logfile logs-max:10 dir:{CWD}/test/lib/utils/tap-testdir-exit-handler-handles-unknown-error-with-logs-and-debug-file/cache/_logs
+verbose logfile logs-max:10 dir:{CWD}/test/lib/utils/tap-testdir-exit-handler-handles-unknown-error-with-logs-and-debug-file/cache/_logs/{DATE}-
 verbose logfile {CWD}/test/lib/utils/tap-testdir-exit-handler-handles-unknown-error-with-logs-and-debug-file/cache/_logs/{DATE}-debug-0.log
 timing npm:load:logFile Completed in {TIME}ms
 timing npm:load:timers Completed in {TIME}ms
diff --git a/tap-snapshots/test/lib/utils/explain-eresolve.js.test.cjs b/tap-snapshots/test/lib/utils/explain-eresolve.js.test.cjs
index 354081d11..99ad5c0f3 100644
--- a/tap-snapshots/test/lib/utils/explain-eresolve.js.test.cjs
+++ b/tap-snapshots/test/lib/utils/explain-eresolve.js.test.cjs
@@ -29,11 +29,9 @@ node_modules/@isaacs/testing-peer-dep-conflict-chain-c
   @isaacs/testing-peer-dep-conflict-chain-c@"1" from the root project
 `
 
-exports[`test/lib/utils/explain-eresolve.js TAP chain-conflict > report 1`] = `
+exports[`test/lib/utils/explain-eresolve.js TAP chain-conflict > report from color 1`] = `
 # npm resolution error report
 
-\${TIME}
-
 While resolving: project@1.2.3
 Found: @isaacs/testing-peer-dep-conflict-chain-d@2.0.0
 node_modules/@isaacs/testing-peer-dep-conflict-chain-d
@@ -45,16 +43,8 @@ node_modules/@isaacs/testing-peer-dep-conflict-chain-c
   @isaacs/testing-peer-dep-conflict-chain-c@"1" from the root project
 
 Fix the upstream dependency conflict, or retry
-this command with --force, or --legacy-peer-deps
+this command with --force or --legacy-peer-deps
 to accept an incorrect (and potentially broken) dependency resolution.
-
-Raw JSON explanation object:
-
-{
-  "name": "chain-conflict",
-  "json": true
-}
-
 `
 
 exports[`test/lib/utils/explain-eresolve.js TAP chain-conflict > report with color 1`] = `
@@ -69,10 +59,8 @@ Could not resolve dependency:
   @isaacs/testing-peer-dep-conflict-chain-c@"1" from the root project
 
 Fix the upstream dependency conflict, or retry
-this command with --force, or --legacy-peer-deps
+this command with --force or --legacy-peer-deps
 to accept an incorrect (and potentially broken) dependency resolution.
-
-See \${REPORT} for a full report.
 `
 
 exports[`test/lib/utils/explain-eresolve.js TAP chain-conflict > report with no color 1`] = `
@@ -87,10 +75,8 @@ node_modules/@isaacs/testing-peer-dep-conflict-chain-c
   @isaacs/testing-peer-dep-conflict-chain-c@"1" from the root project
 
 Fix the upstream dependency conflict, or retry
-this command with --force, or --legacy-peer-deps
+this command with --force or --legacy-peer-deps
 to accept an incorrect (and potentially broken) dependency resolution.
-
-See \${REPORT} for a full report.
 `
 
 exports[`test/lib/utils/explain-eresolve.js TAP cycleNested > explain with color, depth of 2 1`] = `
@@ -130,11 +116,9 @@ node_modules/@isaacs/peer-dep-cycle-c
       @isaacs/peer-dep-cycle-a@"1.x" from the root project
 `
 
-exports[`test/lib/utils/explain-eresolve.js TAP cycleNested > report 1`] = `
+exports[`test/lib/utils/explain-eresolve.js TAP cycleNested > report from color 1`] = `
 # npm resolution error report
 
-\${TIME}
-
 Found: @isaacs/peer-dep-cycle-c@2.0.0
 node_modules/@isaacs/peer-dep-cycle-c
   @isaacs/peer-dep-cycle-c@"2.x" from the root project
@@ -155,14 +139,6 @@ node_modules/@isaacs/peer-dep-cycle-c
 Fix the upstream dependency conflict, or retry
 this command with --no-strict-peer-deps, --force, or --legacy-peer-deps
 to accept an incorrect (and potentially broken) dependency resolution.
-
-Raw JSON explanation object:
-
-{
-  "name": "cycleNested",
-  "json": true
-}
-
 `
 
 exports[`test/lib/utils/explain-eresolve.js TAP cycleNested > report with color 1`] = `
@@ -186,8 +162,6 @@ Conflicting peer dependency: @isaacs/peer-dep-cycle-c@1.0.0[2
 Fix the upstream dependency conflict, or retry
 this command with --no-strict-peer-deps, --force, or --legacy-peer-deps
 to accept an incorrect (and potentially broken) dependency resolution.
-
-See \${REPORT} for a full report.
 `
 
 exports[`test/lib/utils/explain-eresolve.js TAP cycleNested > report with no color 1`] = `
@@ -211,8 +185,6 @@ node_modules/@isaacs/peer-dep-cycle-c
 Fix the upstream dependency conflict, or retry
 this command with --no-strict-peer-deps, --force, or --legacy-peer-deps
 to accept an incorrect (and potentially broken) dependency resolution.
-
-See \${REPORT} for a full report.
 `
 
 exports[`test/lib/utils/explain-eresolve.js TAP eslint-plugin case > explain with color, depth of 2 1`] = `
@@ -255,11 +227,9 @@ node_modules/eslint
     dev eslint-plugin-eslint-plugin@"^3.1.0" from the root project
 `
 
-exports[`test/lib/utils/explain-eresolve.js TAP eslint-plugin case > report 1`] = `
+exports[`test/lib/utils/explain-eresolve.js TAP eslint-plugin case > report from color 1`] = `
 # npm resolution error report
 
-\${TIME}
-
 While resolving: eslint-plugin-react@7.24.0
 Found: eslint@6.8.0
 node_modules/eslint
@@ -287,16 +257,8 @@ node_modules/eslint
     dev eslint-plugin-eslint-plugin@"^3.1.0" from the root project
 
 Fix the upstream dependency conflict, or retry
-this command with --force, or --legacy-peer-deps
+this command with --force or --legacy-peer-deps
 to accept an incorrect (and potentially broken) dependency resolution.
-
-Raw JSON explanation object:
-
-{
-  "name": "eslint-plugin case",
-  "json": true
-}
-
 `
 
 exports[`test/lib/utils/explain-eresolve.js TAP eslint-plugin case > report with color 1`] = `
@@ -319,10 +281,8 @@ Conflicting peer dependency: eslint@7.31.0
     dev eslint-plugin-eslint-plugin@"^3.1.0" from the root project
 
 Fix the upstream dependency conflict, or retry
-this command with --force, or --legacy-peer-deps
+this command with --force or --legacy-peer-deps
 to accept an incorrect (and potentially broken) dependency resolution.
-
-See \${REPORT} for a full report.
 `
 
 exports[`test/lib/utils/explain-eresolve.js TAP eslint-plugin case > report with no color 1`] = `
@@ -345,10 +305,8 @@ node_modules/eslint
     dev eslint-plugin-eslint-plugin@"^3.1.0" from the root project
 
 Fix the upstream dependency conflict, or retry
-this command with --force, or --legacy-peer-deps
+this command with --force or --legacy-peer-deps
 to accept an incorrect (and potentially broken) dependency resolution.
-
-See \${REPORT} for a full report.
 `
 
 exports[`test/lib/utils/explain-eresolve.js TAP gatsby > explain with color, depth of 2 1`] = `
@@ -391,11 +349,9 @@ node_modules/ink-box
         gatsby@"" from the root project
 `
 
-exports[`test/lib/utils/explain-eresolve.js TAP gatsby > report 1`] = `
+exports[`test/lib/utils/explain-eresolve.js TAP gatsby > report from color 1`] = `
 # npm resolution error report
 
-\${TIME}
-
 While resolving: gatsby-recipes@0.2.31
 Found: ink@3.0.0-7
 node_modules/ink
@@ -421,14 +377,6 @@ node_modules/ink-box
 Fix the upstream dependency conflict, or retry
 this command with --no-strict-peer-deps, --force, or --legacy-peer-deps
 to accept an incorrect (and potentially broken) dependency resolution.
-
-Raw JSON explanation object:
-
-{
-  "name": "gatsby",
-  "json": true
-}
-
 `
 
 exports[`test/lib/utils/explain-eresolve.js TAP gatsby > report with color 1`] = `
@@ -456,8 +404,6 @@ Could not resolve dependency:
 Fix the upstream dependency conflict, or retry
 this command with --no-strict-peer-deps, --force, or --legacy-peer-deps
 to accept an incorrect (and potentially broken) dependency resolution.
-
-See \${REPORT} for a full report.
 `
 
 exports[`test/lib/utils/explain-eresolve.js TAP gatsby > report with no color 1`] = `
@@ -485,8 +431,6 @@ node_modules/ink-box
 Fix the upstream dependency conflict, or retry
 this command with --no-strict-peer-deps, --force, or --legacy-peer-deps
 to accept an incorrect (and potentially broken) dependency resolution.
-
-See \${REPORT} for a full report.
 `
 
 exports[`test/lib/utils/explain-eresolve.js TAP no current node, but has current edge > explain with color, depth of 2 1`] = `
@@ -509,11 +453,9 @@ node_modules/eslint-plugin-jsdoc
   dev eslint-plugin-jsdoc@"^22.1.0" from the root project
 `
 
-exports[`test/lib/utils/explain-eresolve.js TAP no current node, but has current edge > report 1`] = `
+exports[`test/lib/utils/explain-eresolve.js TAP no current node, but has current edge > report from color 1`] = `
 # npm resolution error report
 
-\${TIME}
-
 While resolving: eslint@7.22.0
 Found: dev eslint@"file:." from the root project
 
@@ -523,16 +465,8 @@ node_modules/eslint-plugin-jsdoc
   dev eslint-plugin-jsdoc@"^22.1.0" from the root project
 
 Fix the upstream dependency conflict, or retry
-this command with --force, or --legacy-peer-deps
+this command with --force or --legacy-peer-deps
 to accept an incorrect (and potentially broken) dependency resolution.
-
-Raw JSON explanation object:
-
-{
-  "name": "no current node, but has current edge",
-  "json": true
-}
-
 `
 
 exports[`test/lib/utils/explain-eresolve.js TAP no current node, but has current edge > report with color 1`] = `
@@ -545,10 +479,8 @@ Could not resolve dependency:
   dev eslint-plugin-jsdoc@"^22.1.0" from the root project
 
 Fix the upstream dependency conflict, or retry
-this command with --force, or --legacy-peer-deps
+this command with --force or --legacy-peer-deps
 to accept an incorrect (and potentially broken) dependency resolution.
-
-See \${REPORT} for a full report.
 `
 
 exports[`test/lib/utils/explain-eresolve.js TAP no current node, but has current edge > report with no color 1`] = `
@@ -561,10 +493,8 @@ node_modules/eslint-plugin-jsdoc
   dev eslint-plugin-jsdoc@"^22.1.0" from the root project
 
 Fix the upstream dependency conflict, or retry
-this command with --force, or --legacy-peer-deps
+this command with --force or --legacy-peer-deps
 to accept an incorrect (and potentially broken) dependency resolution.
-
-See \${REPORT} for a full report.
 `
 
 exports[`test/lib/utils/explain-eresolve.js TAP no current node, no current edge, idk > explain with color, depth of 2 1`] = `
@@ -591,11 +521,9 @@ node_modules/eslint-plugin-jsdoc
   dev eslint-plugin-jsdoc@"^22.1.0" from the root project
 `
 
-exports[`test/lib/utils/explain-eresolve.js TAP no current node, no current edge, idk > report 1`] = `
+exports[`test/lib/utils/explain-eresolve.js TAP no current node, no current edge, idk > report from color 1`] = `
 # npm resolution error report
 
-\${TIME}
-
 While resolving: eslint@7.22.0
 Found: peer eslint@"^6.0.0" from eslint-plugin-jsdoc@22.2.0
 node_modules/eslint-plugin-jsdoc
@@ -607,16 +535,8 @@ node_modules/eslint-plugin-jsdoc
   dev eslint-plugin-jsdoc@"^22.1.0" from the root project
 
 Fix the upstream dependency conflict, or retry
-this command with --force, or --legacy-peer-deps
+this command with --force or --legacy-peer-deps
 to accept an incorrect (and potentially broken) dependency resolution.
-
-Raw JSON explanation object:
-
-{
-  "name": "no current node, no current edge, idk",
-  "json": true
-}
-
 `
 
 exports[`test/lib/utils/explain-eresolve.js TAP no current node, no current edge, idk > report with color 1`] = `
@@ -631,10 +551,8 @@ Could not resolve dependency:
   dev eslint-plugin-jsdoc@"^22.1.0" from the root project
 
 Fix the upstream dependency conflict, or retry
-this command with --force, or --legacy-peer-deps
+this command with --force or --legacy-peer-deps
 to accept an incorrect (and potentially broken) dependency resolution.
-
-See \${REPORT} for a full report.
 `
 
 exports[`test/lib/utils/explain-eresolve.js TAP no current node, no current edge, idk > report with no color 1`] = `
@@ -649,10 +567,8 @@ node_modules/eslint-plugin-jsdoc
   dev eslint-plugin-jsdoc@"^22.1.0" from the root project
 
 Fix the upstream dependency conflict, or retry
-this command with --force, or --legacy-peer-deps
+this command with --force or --legacy-peer-deps
 to accept an incorrect (and potentially broken) dependency resolution.
-
-See \${REPORT} for a full report.
 `
 
 exports[`test/lib/utils/explain-eresolve.js TAP withShrinkwrap > explain with color, depth of 2 1`] = `
@@ -682,11 +598,9 @@ node_modules/@isaacs/peer-dep-cycle-b
     @isaacs/peer-dep-cycle-a@"1.x" from the root project
 `
 
-exports[`test/lib/utils/explain-eresolve.js TAP withShrinkwrap > report 1`] = `
+exports[`test/lib/utils/explain-eresolve.js TAP withShrinkwrap > report from color 1`] = `
 # npm resolution error report
 
-\${TIME}
-
 While resolving: @isaacs/peer-dep-cycle-b@1.0.0
 Found: @isaacs/peer-dep-cycle-c@2.0.0
 node_modules/@isaacs/peer-dep-cycle-c
@@ -702,14 +616,6 @@ node_modules/@isaacs/peer-dep-cycle-b
 Fix the upstream dependency conflict, or retry
 this command with --no-strict-peer-deps, --force, or --legacy-peer-deps
 to accept an incorrect (and potentially broken) dependency resolution.
-
-Raw JSON explanation object:
-
-{
-  "name": "withShrinkwrap",
-  "json": true
-}
-
 `
 
 exports[`test/lib/utils/explain-eresolve.js TAP withShrinkwrap > report with color 1`] = `
@@ -728,8 +634,6 @@ Could not resolve dependency:
 Fix the upstream dependency conflict, or retry
 this command with --no-strict-peer-deps, --force, or --legacy-peer-deps
 to accept an incorrect (and potentially broken) dependency resolution.
-
-See \${REPORT} for a full report.
 `
 
 exports[`test/lib/utils/explain-eresolve.js TAP withShrinkwrap > report with no color 1`] = `
@@ -748,6 +652,4 @@ node_modules/@isaacs/peer-dep-cycle-b
 Fix the upstream dependency conflict, or retry
 this command with --no-strict-peer-deps, --force, or --legacy-peer-deps
 to accept an incorrect (and potentially broken) dependency resolution.
-
-See \${REPORT} for a full report.
 `
diff --git a/tap-snapshots/test/lib/utils/log-file.js.test.cjs b/tap-snapshots/test/lib/utils/log-file.js.test.cjs
index 7a3918493..912a4365f 100644
--- a/tap-snapshots/test/lib/utils/log-file.js.test.cjs
+++ b/tap-snapshots/test/lib/utils/log-file.js.test.cjs
@@ -6,7 +6,7 @@
  */
 'use strict'
 exports[`test/lib/utils/log-file.js TAP snapshot > must match snapshot 1`] = `
-0 verbose logfile logs-max:10 dir:{CWD}/test/lib/utils/tap-testdir-log-file-snapshot
+0 verbose logfile logs-max:10 dir:{CWD}/test/lib/utils/tap-testdir-log-file-snapshot/{DATE}-
 1 silly logfile done cleaning log files
 2 error no prefix
 3 error prefix with prefix
diff --git a/test/lib/utils/error-message.js b/test/lib/utils/error-message.js
index 3fec501ef..29753c303 100644
--- a/test/lib/utils/error-message.js
+++ b/test/lib/utils/error-message.js
@@ -4,6 +4,12 @@ const { load: _loadMockNpm } = require('../../fixtures/mock-npm.js')
 const mockGlobals = require('../../fixtures/mock-globals.js')
 const { cleanCwd, cleanDate } = require('../../fixtures/clean-snapshot.js')
 
+t.formatSnapshot = (p) => {
+  if (Array.isArray(p.files) && !p.files.length) {
+    delete p.files
+  }
+  return p
+}
 t.cleanSnapshot = p => cleanDate(cleanCwd(p))
 
 mockGlobals(t, {
@@ -420,7 +426,7 @@ t.test('bad platform', async t => {
 })
 
 t.test('explain ERESOLVE errors', async t => {
-  const npm = await loadMockNpm(t)
+  const { npm, ...rest } = await loadMockNpm(t)
   const EXPLAIN_CALLED = []
 
   const er = Object.assign(new Error('could not resolve'), {
@@ -428,19 +434,16 @@ t.test('explain ERESOLVE errors', async t => {
   })
 
   t.matchSnapshot(errorMessage(er, {
-    ...npm,
+    npm,
+    ...rest,
     mocks: {
       '../../../lib/utils/explain-eresolve.js': {
         report: (...args) => {
           EXPLAIN_CALLED.push(args)
-          return 'explanation'
+          return { explanation: 'explanation', file: 'report' }
         },
       },
     },
   }))
-  t.match(EXPLAIN_CALLED, [[
-    er,
-    false,
-    path.resolve(npm.cache, 'eresolve-report.txt'),
-  ]])
+  t.match(EXPLAIN_CALLED, [[er, false]])
 })
diff --git a/test/lib/utils/exit-handler.js b/test/lib/utils/exit-handler.js
index de4ce61aa..1378d7b75 100644
--- a/test/lib/utils/exit-handler.js
+++ b/test/lib/utils/exit-handler.js
@@ -1,5 +1,7 @@
 const t = require('tap')
 const os = require('os')
+const fs = require('@npmcli/fs')
+const { join } = require('path')
 const EventEmitter = require('events')
 const { format } = require('../../../lib/utils/log-file')
 const { load: loadMockNpm } = require('../../fixtures/mock-npm')
@@ -45,7 +47,7 @@ mockGlobals(t, {
   }),
 }, { replace: true })
 
-const mockExitHandler = async (t, { init, load, testdir, config, globals, mocks } = {}) => {
+const mockExitHandler = async (t, { init, load, testdir, config, mocks, files } = {}) => {
   const errors = []
 
   const { npm, logMocks, ...rest } = await loadMockNpm(t, {
@@ -69,9 +71,9 @@ const mockExitHandler = async (t, { init, load, testdir, config, globals, mocks
 
   const exitHandler = t.mock('../../../lib/utils/exit-handler.js', {
     '../../../lib/utils/error-message.js': (err) => ({
-      ...err,
       summary: [['ERR SUMMARY', err.message]],
       detail: [['ERR DETAIL', err.message]],
+      ...(files ? { files } : {}),
     }),
     os: {
       type: () => 'Foo',
@@ -311,6 +313,55 @@ t.test('log file error', async (t) => {
   t.match(logs.error.filter(([t]) => t === ''), [['', `error writing to the directory`]])
 })
 
+t.test('files from error message', async (t) => {
+  const { exitHandler, logs, cache } = await mockExitHandler(t, {
+    files: [
+      ['error-file.txt', '# error file content'],
+    ],
+  })
+
+  await exitHandler(err('Error message'))
+
+  const logFiles = fs.readdirSync(join(cache, '_logs'))
+  const errorFileName = logFiles.find(f => f.endsWith('error-file.txt'))
+  const errorFile = fs.readFileSync(join(cache, '_logs', errorFileName)).toString()
+
+  const [log] = logs.error.filter(([t]) => t === '')
+
+  t.match(log[1], /For a full report see:\n.*-error-file\.txt/)
+  t.match(errorFile, '# error file content')
+  t.match(errorFile, 'Log files:')
+})
+
+t.test('files from error message with error', async (t) => {
+  const { exitHandler, logs } = await mockExitHandler(t, {
+    config: {
+      'logs-dir': 'LOGS_DIR',
+    },
+    files: [
+      ['error-file.txt', '# error file content'],
+    ],
+    mocks: {
+      '@npmcli/fs': {
+        ...fs,
+        writeFileSync: (dir) => {
+          console.log(dir)
+          if (dir.includes('LOGS_DIR') && dir.endsWith('error-file.txt')) {
+            console.log('throw')
+            throw new Error('err')
+          }
+        },
+      },
+    },
+  })
+
+  await exitHandler(err('Error message'))
+
+  const [log] = logs.warn.filter(([t]) => t === '')
+
+  t.match(log[1], /Could not write error message to.*error-file\.txt.*err/)
+})
+
 t.test('timing with no error', async (t) => {
   const { exitHandler, timingFile, npm, logs } = await mockExitHandler(t, {
     config: { timing: true },
diff --git a/test/lib/utils/explain-eresolve.js b/test/lib/utils/explain-eresolve.js
index f9710ee88..2c1fed778 100644
--- a/test/lib/utils/explain-eresolve.js
+++ b/test/lib/utils/explain-eresolve.js
@@ -1,41 +1,32 @@
 const t = require('tap')
-const npm = {}
-const { explain, report } = require('../../../lib/utils/explain-eresolve.js')
-const { statSync, readFileSync, unlinkSync } = require('fs')
-// strip out timestamps from reports
-const read = f => readFileSync(f, 'utf8')
-  .replace(/\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}.\d{3}Z/g, '${TIME}')
-
 const { resolve } = require('path')
+const { explain, report } = require('../../../lib/utils/explain-eresolve.js')
 
 const cases = require('../../fixtures/eresolve-explanations.js')
+const { cleanDate } = require('../../fixtures/clean-snapshot.js')
 
 for (const [name, expl] of Object.entries(cases)) {
   // no sense storing the whole contents of each object in the snapshot
   // we can trust that JSON.stringify still works just fine.
-  expl.toJSON = () => {
-    return { name, json: true }
-  }
+  expl.toJSON = () => ({ name, json: true })
 
   t.test(name, t => {
-    npm.cache = t.testdir()
-    const reportFile = resolve(npm.cache, 'eresolve-report.txt')
-    t.cleanSnapshot = str => str.split(reportFile).join('${REPORT}')
+    const dir = t.testdir()
+    const fileReport = resolve(dir, 'eresolve-report.txt')
+    const opts = { file: fileReport, date: new Date().toISOString() }
+
+    t.cleanSnapshot = str => cleanDate(str.split(fileReport).join('${REPORT}'))
 
-    npm.color = true
-    t.matchSnapshot(report(expl, true, reportFile), 'report with color')
-    const reportData = read(reportFile)
-    t.matchSnapshot(reportData, 'report')
-    unlinkSync(reportFile)
+    const color = report(expl, true, opts)
+    t.matchSnapshot(color.explanation, 'report with color')
+    t.matchSnapshot(color.file, 'report from color')
 
-    t.matchSnapshot(report(expl, false, reportFile), 'report with no color')
-    t.equal(read(reportFile), reportData, 'same report written for object')
-    unlinkSync(reportFile)
+    const noColor = report(expl, false, opts)
+    t.matchSnapshot(noColor.explanation, 'report with no color')
+    t.equal(noColor.file, color.file, 'same report written for object')
 
     t.matchSnapshot(explain(expl, true, 2), 'explain with color, depth of 2')
-    t.throws(() => statSync(reportFile), { code: 'ENOENT' }, 'no report')
     t.matchSnapshot(explain(expl, false, 6), 'explain with no color, depth of 6')
-    t.throws(() => statSync(reportFile), { code: 'ENOENT' }, 'no report')
 
     t.end()
   })
diff --git a/test/lib/utils/log-file.js b/test/lib/utils/log-file.js
index 3c7bb3fe8..41a0bc5a5 100644
--- a/test/lib/utils/log-file.js
+++ b/test/lib/utils/log-file.js
@@ -6,11 +6,11 @@ const os = require('os')
 const fsMiniPass = require('fs-minipass')
 const rimraf = require('rimraf')
 const LogFile = require('../../../lib/utils/log-file.js')
-const runId = require('../../../lib/utils/run-id.js')
-const { cleanCwd } = require('../../fixtures/clean-snapshot')
+const { cleanCwd, cleanDate } = require('../../fixtures/clean-snapshot')
 
-t.cleanSnapshot = (path) => cleanCwd(path)
+t.cleanSnapshot = (path) => cleanDate(cleanCwd(path))
 
+const getId = (d = new Date()) => d.toISOString().replace(/[.:]/g, '_')
 const last = arr => arr[arr.length - 1]
 const range = (n) => Array.from(Array(n).keys())
 const makeOldLogs = (count, oldStyle) => {
@@ -20,7 +20,7 @@ const makeOldLogs = (count, oldStyle) => {
   return range(oldStyle ? count : (count / 2)).reduce((acc, i) => {
     const cloneDate = new Date(d.getTime())
     cloneDate.setSeconds(i)
-    const dateId = runId(cloneDate)
+    const dateId = getId(cloneDate)
     if (oldStyle) {
       acc[`${dateId}-debug.log`] = 'hello'
     } else {
@@ -42,10 +42,15 @@ const cleanErr = (message) => {
 
 const loadLogFile = async (t, { buffer = [], mocks, testdir = {}, ...options } = {}) => {
   const root = t.testdir(testdir)
+
   const MockLogFile = t.mock('../../../lib/utils/log-file.js', mocks)
   const logFile = new MockLogFile(Object.keys(options).length ? options : undefined)
+
   buffer.forEach((b) => logFile.log(...b))
-  await logFile.load({ dir: root, ...options })
+
+  const id = getId()
+  await logFile.load({ path: (f = '') => path.join(root, `${id}-${f}`), ...options })
+
   t.teardown(() => logFile.off())
   return {
     root,
diff --git a/test/lib/utils/timers.js b/test/lib/utils/timers.js
index 259ecd5dd..eee7aea14 100644
--- a/test/lib/utils/timers.js
+++ b/test/lib/utils/timers.js
@@ -68,11 +68,11 @@ t.test('finish unstarted timer', async (t) => {
 })
 
 t.test('writes file', async (t) => {
-  const { timers } = mockTimers(t, { id: 'TIMING_FILE' })
+  const { timers } = mockTimers(t)
   const dir = t.testdir()
   process.emit('time', 'foo')
   process.emit('timeEnd', 'foo')
-  timers.load({ dir })
+  timers.load({ path: (f) => resolve(dir, `TIMING_FILE-${f}`) })
   timers.writeFile({ some: 'data' })
   const data = JSON.parse(fs.readFileSync(resolve(dir, 'TIMING_FILE-timing.json')))
   t.match(data, {
@@ -88,7 +88,7 @@ t.test('fails to write file', async (t) => {
   const { logs, timers } = mockTimers(t)
   const dir = t.testdir()
 
-  timers.load({ dir: join(dir, 'does', 'not', 'exist') })
+  timers.load({ path: () => join(dir, 'does', 'not', 'exist') })
   timers.writeFile()
 
   t.match(logs.warn, [['timing', 'could not write timing file']])