The rebase drill records a commit sha that changes on every run, so real evidence changes and timestamp noise look identical #292

Open
Open
The rebase drill records a commit sha that changes on every run, so real evidence changes and timestamp noise look identical#292
Labels
area/coreCore libraries and shared logic

Description

@pseudoseed
pseudoseed
opened on Aug 31, 2026

Established by builder pir-272 on 2026-08-31 while explaining a field in PR #291.

The field

codev/research/250-rebase-drill.json records contractRegeneration.source.commit. It is a throwaway merge commit that exists only inside the drill's scratch clone, written at rebase-drill.mjs:445-449:

git commit-tree <merged-tree-sha> -p <forkHead> -p <target> -m 'spec 250 drill: merged tree'

It is never pushed and is in neither real checkout. It exists because generate.mjs refuses any checkout whose HEAD is not pin.commit, so proving the contract still regenerates after a rebase needs a commit that did not exist before the rebase.

The problem

git commit-tree stamps author and committer time into the object, and the drill pins neither. So this sha changes on every drill run, even when both parents and the tree are byte-identical.

That means the recorded value is not an identifier of anything. Two runs of the same drill against the same inputs produce different evidence, and a reader comparing evidence across runs sees a change that carries no information.

It also means "regeneration output is byte-identical apart from the source hash" can never be quite true for this file, so a real change and a timestamp are spelled the same way in a diff. Anyone reviewing an evidence update has to know this field is noise, and nothing in the file says so.

What would close this

  • Pin GIT_AUTHOR_DATE and GIT_COMMITTER_DATE when writing the drill commit, so the sha is a function of its inputs and a change to it means an input changed.
  • Or stop recording the sha, and record what it is derived from: the two parent commits and the merged tree sha. Those are already stable.
  • Either way the field should say what it is. kind currently says "the three-way merge of the same two trees, written by git merge-tree", which is accurate about the object and silent about its stability.

Not a defect in PR #291

In that PR the sha moved for a real reason: one parent moved, 2f64a1b0ee2b to 26b4c2dc09f0, while the upstream target stayed at 9b2d04317c68. The builder measured both parents rather than inferring. This issue is about the field being unstable in general, which is what makes that check expensive to do by hand every time.

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      , 'i'); if (__m === '*' || __re.test(location.href)) { injectUserscript("// Add copy buttons to all 
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var __m = "github.com";
var __re = new RegExp('^' + "github\\.com" + '

      Skip to content
      The rebase drill records a commit sha that changes on every run, so real evidence changes and timestamp noise look identical #292
      Open
      Open
      The rebase drill records a commit sha that changes on every run, so real evidence changes and timestamp noise look identical#292
      Labels
      area/coreCore libraries and shared logic
      Description
      @pseudoseed
      pseudoseed
      opened on Aug 31, 2026
      Established by builder pir-272 on 2026-08-31 while explaining a field in PR #291.
      The field
      codev/research/250-rebase-drill.json records contractRegeneration.source.commit. It is a throwaway merge commit that exists only inside the drill's scratch clone, written at rebase-drill.mjs:445-449:
      git commit-tree <merged-tree-sha> -p <forkHead> -p <target> -m 'spec 250 drill: merged tree'

      It is never pushed and is in neither real checkout. It exists because generate.mjs refuses any checkout whose HEAD is not pin.commit, so proving the contract still regenerates after a rebase needs a commit that did not exist before the rebase.
      The problem
      git commit-tree stamps author and committer time into the object, and the drill pins neither. So this sha changes on every drill run, even when both parents and the tree are byte-identical.
      That means the recorded value is not an identifier of anything. Two runs of the same drill against the same inputs produce different evidence, and a reader comparing evidence across runs sees a change that carries no information.
      It also means "regeneration output is byte-identical apart from the source hash" can never be quite true for this file, so a real change and a timestamp are spelled the same way in a diff. Anyone reviewing an evidence update has to know this field is noise, and nothing in the file says so.
      What would close this
      • Pin GIT_AUTHOR_DATE and GIT_COMMITTER_DATE when writing the drill commit, so the sha is a function of its inputs and a change to it means an input changed.
      • Or stop recording the sha, and record what it is derived from: the two parent commits and the merged tree sha. Those are already stable.
      • Either way the field should say what it is. kind currently says "the three-way merge of the same two trees, written by git merge-tree", which is accurate about the object and silent about its stability.
      Not a defect in PR #291
      In that PR the sha moved for a real reason: one parent moved, 2f64a1b0ee2b to 26b4c2dc09f0, while the upstream target stayed at 9b2d04317c68. The builder measured both parents rather than inferring. This issue is about the field being unstable in general, which is what makes that check expensive to do by hand every time.
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, 'i');
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var __m = "*";
var __re = new RegExp('^' + ".*" + '

          Skip to content
          The rebase drill records a commit sha that changes on every run, so real evidence changes and timestamp noise look identical #292
          Open
          Open
          The rebase drill records a commit sha that changes on every run, so real evidence changes and timestamp noise look identical#292
          Labels
          area/coreCore libraries and shared logic
          Description
          @pseudoseed
          pseudoseed
          opened on Aug 31, 2026
          Established by builder pir-272 on 2026-08-31 while explaining a field in PR #291.
          The field
          codev/research/250-rebase-drill.json records contractRegeneration.source.commit. It is a throwaway merge commit that exists only inside the drill's scratch clone, written at rebase-drill.mjs:445-449:
          git commit-tree <merged-tree-sha> -p <forkHead> -p <target> -m 'spec 250 drill: merged tree'

          It is never pushed and is in neither real checkout. It exists because generate.mjs refuses any checkout whose HEAD is not pin.commit, so proving the contract still regenerates after a rebase needs a commit that did not exist before the rebase.
          The problem
          git commit-tree stamps author and committer time into the object, and the drill pins neither. So this sha changes on every drill run, even when both parents and the tree are byte-identical.
          That means the recorded value is not an identifier of anything. Two runs of the same drill against the same inputs produce different evidence, and a reader comparing evidence across runs sees a change that carries no information.
          It also means "regeneration output is byte-identical apart from the source hash" can never be quite true for this file, so a real change and a timestamp are spelled the same way in a diff. Anyone reviewing an evidence update has to know this field is noise, and nothing in the file says so.
          What would close this
          • Pin GIT_AUTHOR_DATE and GIT_COMMITTER_DATE when writing the drill commit, so the sha is a function of its inputs and a change to it means an input changed.
          • Or stop recording the sha, and record what it is derived from: the two parent commits and the merged tree sha. Those are already stable.
          • Either way the field should say what it is. kind currently says "the three-way merge of the same two trees, written by git merge-tree", which is accurate about the object and silent about its stability.
          Not a defect in PR #291
          In that PR the sha moved for a real reason: one parent moved, 2f64a1b0ee2b to 26b4c2dc09f0, while the upstream target stayed at 9b2d04317c68. The builder measured both parents rather than inferring. This issue is about the field being unstable in general, which is what makes that check expensive to do by hand every time.
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, 'i');
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injectUserscript("// Highlight search terms from Google/DuckDuckGo/Bing referrer\n(function() {\n var ref = document.referrer;\n var terms = [];\n \n if (ref.includes('google.com') || ref.includes('duckduckgo.com') || ref.includes('bing.com')) {\n var url = new URL(ref);\n var q = url.searchParams.get('q') || url.searchParams.get('p');\n if (q) {\n terms = q.split(/\\s+/).filter(function(t) { return t.length > 2; });\n }\n }\n \n if (terms.length === 0) return;\n \n var style = document.createElement('style');\n style.textContent = '.userscript-highlight { background: #fbbf24; color: #1a1a2e; padding: 1px 3px; border-radius: 2px; }';\n document.head.appendChild(style);\n \n function highlight(node) {\n if (node.nodeType === 3) { // text node\n var text = node.textContent;\n var found = false;\n terms.forEach(function(term) {\n var regex = new RegExp('(' + term.replace(/[.*+?^${}()|[\\]\\\\]/g, '\\\\') + ')', 'gi');\n if (regex.test(text)) {\n found = true;\n var frag = document.createDocumentFragment();\n var parts = text.split(regex);\n parts.forEach(function(part, i) {\n if (i % 2 === 0) {\n frag.appendChild(document.createTextNode(part));\n } else {\n var span = document.createElement('span');\n span.className = 'userscript-highlight';\n span.textContent = part;\n frag.appendChild(span);\n }\n });\n node.parentNode.replaceChild(frag, node);\n }\n });\n } else if (node.nodeType === 1 && node.childNodes) { // element\n var skipTags = ['SCRIPT', 'STYLE', 'NOSCRIPT', 'TEXTAREA', 'INPUT', 'SELECT'];\n if (!skipTags.includes(node.tagName)) {\n Array.from(node.childNodes).forEach(highlight);\n }\n }\n }\n \n highlight(document.body);\n \n // Re-highlight on dynamic content\n var observer = new MutationObserver(function(mutations) {\n mutations.forEach(function(m) {\n m.addedNodes.forEach(function(node) {\n if (node.nodeType === 1 || node.nodeType === 3) highlight(node);\n });\n });\n });\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Highlight Search Terms");
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(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

              Skip to content
              The rebase drill records a commit sha that changes on every run, so real evidence changes and timestamp noise look identical #292
              Open
              Open
              The rebase drill records a commit sha that changes on every run, so real evidence changes and timestamp noise look identical#292
              Labels
              area/coreCore libraries and shared logic
              Description
              @pseudoseed
              pseudoseed
              opened on Aug 31, 2026
              Established by builder pir-272 on 2026-08-31 while explaining a field in PR #291.
              The field
              codev/research/250-rebase-drill.json records contractRegeneration.source.commit. It is a throwaway merge commit that exists only inside the drill's scratch clone, written at rebase-drill.mjs:445-449:
              git commit-tree <merged-tree-sha> -p <forkHead> -p <target> -m 'spec 250 drill: merged tree'

              It is never pushed and is in neither real checkout. It exists because generate.mjs refuses any checkout whose HEAD is not pin.commit, so proving the contract still regenerates after a rebase needs a commit that did not exist before the rebase.
              The problem
              git commit-tree stamps author and committer time into the object, and the drill pins neither. So this sha changes on every drill run, even when both parents and the tree are byte-identical.
              That means the recorded value is not an identifier of anything. Two runs of the same drill against the same inputs produce different evidence, and a reader comparing evidence across runs sees a change that carries no information.
              It also means "regeneration output is byte-identical apart from the source hash" can never be quite true for this file, so a real change and a timestamp are spelled the same way in a diff. Anyone reviewing an evidence update has to know this field is noise, and nothing in the file says so.
              What would close this
              • Pin GIT_AUTHOR_DATE and GIT_COMMITTER_DATE when writing the drill commit, so the sha is a function of its inputs and a change to it means an input changed.
              • Or stop recording the sha, and record what it is derived from: the two parent commits and the merged tree sha. Those are already stable.
              • Either way the field should say what it is. kind currently says "the three-way merge of the same two trees, written by git merge-tree", which is accurate about the object and silent about its stability.
              Not a defect in PR #291
              In that PR the sha moved for a real reason: one parent moved, 2f64a1b0ee2b to 26b4c2dc09f0, while the upstream target stayed at 9b2d04317c68. The builder measured both parents rather than inferring. This issue is about the field being unstable in general, which is what makes that check expensive to do by hand every time.
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                area/coreCore libraries and shared logic
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                  None yet
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                  No branches or pull requests
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, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Strip utm_, fbclid, gclid, etc. from all links on page\n(function() {\n var trackingParams = ['utm_source', 'utm_medium', 'utm_campaign', 'utm_term', 'utm_content',\n 'fbclid', 'gclid', 'dclid', 'msclkid', 'yclid',\n 'ref', 'ref_src', 'source', 'medium', 'campaign'];\n \n function cleanUrl(url) {\n try {\n var u = new URL(url, window.location.origin);\n var changed = false;\n trackingParams.forEach(function(p) {\n if (u.searchParams.has(p)) {\n u.searchParams.delete(p);\n changed = true;\n }\n });\n return changed ? u.toString() : url;\n } catch (e) {\n return url;\n }\n }\n \n function cleanLinks() {\n document.querySelectorAll('a[href]').forEach(function(a) {\n var clean = cleanUrl(a.href);\n if (clean !== a.href) a.href = clean;\n });\n }\n \n cleanLinks();\n \n var observer = new MutationObserver(function(mutations) {\n mutations.forEach(function(m) {\n m.addedNodes.forEach(function(node) {\n if (node.nodeType === 1) {\n if (node.tagName === 'A') cleanLinks();\n node.querySelectorAll('a[href]').forEach(function(a) {\n var clean = cleanUrl(a.href);\n if (clean !== a.href) a.href = clean;\n });\n }\n });\n });\n });\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Remove Tracking Parameters from Links");
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var __m = "youtube.com";
var __re = new RegExp('^' + "youtube\\.com" + '

                  Skip to content
                  The rebase drill records a commit sha that changes on every run, so real evidence changes and timestamp noise look identical #292
                  Open
                  Open
                  The rebase drill records a commit sha that changes on every run, so real evidence changes and timestamp noise look identical#292
                  Labels
                  area/coreCore libraries and shared logic
                  Description
                  @pseudoseed
                  pseudoseed
                  opened on Aug 31, 2026
                  Established by builder pir-272 on 2026-08-31 while explaining a field in PR #291.
                  The field
                  codev/research/250-rebase-drill.json records contractRegeneration.source.commit. It is a throwaway merge commit that exists only inside the drill's scratch clone, written at rebase-drill.mjs:445-449:
                  git commit-tree <merged-tree-sha> -p <forkHead> -p <target> -m 'spec 250 drill: merged tree'

                  It is never pushed and is in neither real checkout. It exists because generate.mjs refuses any checkout whose HEAD is not pin.commit, so proving the contract still regenerates after a rebase needs a commit that did not exist before the rebase.
                  The problem
                  git commit-tree stamps author and committer time into the object, and the drill pins neither. So this sha changes on every drill run, even when both parents and the tree are byte-identical.
                  That means the recorded value is not an identifier of anything. Two runs of the same drill against the same inputs produce different evidence, and a reader comparing evidence across runs sees a change that carries no information.
                  It also means "regeneration output is byte-identical apart from the source hash" can never be quite true for this file, so a real change and a timestamp are spelled the same way in a diff. Anyone reviewing an evidence update has to know this field is noise, and nothing in the file says so.
                  What would close this
                  • Pin GIT_AUTHOR_DATE and GIT_COMMITTER_DATE when writing the drill commit, so the sha is a function of its inputs and a change to it means an input changed.
                  • Or stop recording the sha, and record what it is derived from: the two parent commits and the merged tree sha. Those are already stable.
                  • Either way the field should say what it is. kind currently says "the three-way merge of the same two trees, written by git merge-tree", which is accurate about the object and silent about its stability.
                  Not a defect in PR #291
                  In that PR the sha moved for a real reason: one parent moved, 2f64a1b0ee2b to 26b4c2dc09f0, while the upstream target stayed at 9b2d04317c68. The builder measured both parents rather than inferring. This issue is about the field being unstable in general, which is what makes that check expensive to do by hand every time.
                  Metadata
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                      None yet
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                      No branches or pull requests
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, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Auto-enable theater mode on YouTube\n(function() {\n function tryTheater() {\n var btn = document.querySelector('button[aria-label=\"Theater mode\"], ytd-player #player button[title=\"Theater mode\"]');\n if (btn && !btn.classList.contains('activated')) {\n btn.click();\n }\n }\n \n // Try immediately\n tryTheater();\n \n // Try after navigation (SPA)\n var lastUrl = location.href;\n setInterval(function() {\n if (location.href !== lastUrl) {\n lastUrl = location.href;\n setTimeout(tryTheater, 500);\n }\n }, 1000);\n \n // Also try on player load\n var observer = new MutationObserver(tryTheater);\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "YouTube Theater Mode Default");
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(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

                      Skip to content
                      The rebase drill records a commit sha that changes on every run, so real evidence changes and timestamp noise look identical #292
                      Open
                      Open
                      The rebase drill records a commit sha that changes on every run, so real evidence changes and timestamp noise look identical#292
                      Labels
                      area/coreCore libraries and shared logic
                      Description
                      @pseudoseed
                      pseudoseed
                      opened on Aug 31, 2026
                      Established by builder pir-272 on 2026-08-31 while explaining a field in PR #291.
                      The field
                      codev/research/250-rebase-drill.json records contractRegeneration.source.commit. It is a throwaway merge commit that exists only inside the drill's scratch clone, written at rebase-drill.mjs:445-449:
                      git commit-tree <merged-tree-sha> -p <forkHead> -p <target> -m 'spec 250 drill: merged tree'

                      It is never pushed and is in neither real checkout. It exists because generate.mjs refuses any checkout whose HEAD is not pin.commit, so proving the contract still regenerates after a rebase needs a commit that did not exist before the rebase.
                      The problem
                      git commit-tree stamps author and committer time into the object, and the drill pins neither. So this sha changes on every drill run, even when both parents and the tree are byte-identical.
                      That means the recorded value is not an identifier of anything. Two runs of the same drill against the same inputs produce different evidence, and a reader comparing evidence across runs sees a change that carries no information.
                      It also means "regeneration output is byte-identical apart from the source hash" can never be quite true for this file, so a real change and a timestamp are spelled the same way in a diff. Anyone reviewing an evidence update has to know this field is noise, and nothing in the file says so.
                      What would close this
                      • Pin GIT_AUTHOR_DATE and GIT_COMMITTER_DATE when writing the drill commit, so the sha is a function of its inputs and a change to it means an input changed.
                      • Or stop recording the sha, and record what it is derived from: the two parent commits and the merged tree sha. Those are already stable.
                      • Either way the field should say what it is. kind currently says "the three-way merge of the same two trees, written by git merge-tree", which is accurate about the object and silent about its stability.
                      Not a defect in PR #291
                      In that PR the sha moved for a real reason: one parent moved, 2f64a1b0ee2b to 26b4c2dc09f0, while the upstream target stayed at 9b2d04317c68. The builder measured both parents rather than inferring. This issue is about the field being unstable in general, which is what makes that check expensive to do by hand every time.
                      Metadata
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                      No one assigned
                        Labels
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                        No projects
                          Milestone
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                          Relationships
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                          No branches or pull requests
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, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Remove or un-stick sticky/fixed headers that block content\n(function() {\n function unstick() {\n document.querySelectorAll('header, nav, [role=\"banner\"], .header, .navbar, .sticky, .fixed-top, [style*=\"position: fixed\"], [style*=\"position:sticky\"]').forEach(function(el) {\n if (el.style.position === 'fixed' || el.style.position === 'sticky' || \n getComputedStyle(el).position === 'fixed' || getComputedStyle(el).position === 'sticky') {\n el.style.position = 'static';\n el.style.top = 'auto';\n el.style.zIndex = 'auto';\n }\n });\n }\n \n unstick();\n \n var observer = new MutationObserver(unstick);\n observer.observe(document.body, { childList: true, subtree: true, attributes: true, attributeFilter: ['style', 'class'] });\n})();", "Kill Sticky Headers");
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(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

                          Skip to content
                          The rebase drill records a commit sha that changes on every run, so real evidence changes and timestamp noise look identical #292
                          Open
                          Open
                          The rebase drill records a commit sha that changes on every run, so real evidence changes and timestamp noise look identical#292
                          Labels
                          area/coreCore libraries and shared logic
                          Description
                          @pseudoseed
                          pseudoseed
                          opened on Aug 31, 2026
                          Established by builder pir-272 on 2026-08-31 while explaining a field in PR #291.
                          The field
                          codev/research/250-rebase-drill.json records contractRegeneration.source.commit. It is a throwaway merge commit that exists only inside the drill's scratch clone, written at rebase-drill.mjs:445-449:
                          git commit-tree <merged-tree-sha> -p <forkHead> -p <target> -m 'spec 250 drill: merged tree'

                          It is never pushed and is in neither real checkout. It exists because generate.mjs refuses any checkout whose HEAD is not pin.commit, so proving the contract still regenerates after a rebase needs a commit that did not exist before the rebase.
                          The problem
                          git commit-tree stamps author and committer time into the object, and the drill pins neither. So this sha changes on every drill run, even when both parents and the tree are byte-identical.
                          That means the recorded value is not an identifier of anything. Two runs of the same drill against the same inputs produce different evidence, and a reader comparing evidence across runs sees a change that carries no information.
                          It also means "regeneration output is byte-identical apart from the source hash" can never be quite true for this file, so a real change and a timestamp are spelled the same way in a diff. Anyone reviewing an evidence update has to know this field is noise, and nothing in the file says so.
                          What would close this
                          • Pin GIT_AUTHOR_DATE and GIT_COMMITTER_DATE when writing the drill commit, so the sha is a function of its inputs and a change to it means an input changed.
                          • Or stop recording the sha, and record what it is derived from: the two parent commits and the merged tree sha. Those are already stable.
                          • Either way the field should say what it is. kind currently says "the three-way merge of the same two trees, written by git merge-tree", which is accurate about the object and silent about its stability.
                          Not a defect in PR #291
                          In that PR the sha moved for a real reason: one parent moved, 2f64a1b0ee2b to 26b4c2dc09f0, while the upstream target stayed at 9b2d04317c68. The builder measured both parents rather than inferring. This issue is about the field being unstable in general, which is what makes that check expensive to do by hand every time.
                          Metadata
                          Metadata
                          Assignees
                          No one assigned
                            Labels
                            area/coreCore libraries and shared logic
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, 'i');
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                              The rebase drill records a commit sha that changes on every run, so real evidence changes and timestamp noise look identical #292
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                              The rebase drill records a commit sha that changes on every run, so real evidence changes and timestamp noise look identical#292
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                              area/coreCore libraries and shared logic
                              Description
                              @pseudoseed
                              pseudoseed
                              opened on Aug 31, 2026
                              Established by builder pir-272 on 2026-08-31 while explaining a field in PR #291.
                              The field
                              codev/research/250-rebase-drill.json records contractRegeneration.source.commit. It is a throwaway merge commit that exists only inside the drill's scratch clone, written at rebase-drill.mjs:445-449:
                              git commit-tree <merged-tree-sha> -p <forkHead> -p <target> -m 'spec 250 drill: merged tree'

                              It is never pushed and is in neither real checkout. It exists because generate.mjs refuses any checkout whose HEAD is not pin.commit, so proving the contract still regenerates after a rebase needs a commit that did not exist before the rebase.
                              The problem
                              git commit-tree stamps author and committer time into the object, and the drill pins neither. So this sha changes on every drill run, even when both parents and the tree are byte-identical.
                              That means the recorded value is not an identifier of anything. Two runs of the same drill against the same inputs produce different evidence, and a reader comparing evidence across runs sees a change that carries no information.
                              It also means "regeneration output is byte-identical apart from the source hash" can never be quite true for this file, so a real change and a timestamp are spelled the same way in a diff. Anyone reviewing an evidence update has to know this field is noise, and nothing in the file says so.
                              What would close this
                              • Pin GIT_AUTHOR_DATE and GIT_COMMITTER_DATE when writing the drill commit, so the sha is a function of its inputs and a change to it means an input changed.
                              • Or stop recording the sha, and record what it is derived from: the two parent commits and the merged tree sha. Those are already stable.
                              • Either way the field should say what it is. kind currently says "the three-way merge of the same two trees, written by git merge-tree", which is accurate about the object and silent about its stability.
                              Not a defect in PR #291
                              In that PR the sha moved for a real reason: one parent moved, 2f64a1b0ee2b to 26b4c2dc09f0, while the upstream target stayed at 9b2d04317c68. The builder measured both parents rather than inferring. This issue is about the field being unstable in general, which is what makes that check expensive to do by hand every time.
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