diff --git a/plugins/git/.apm/skills/git-history/README.md b/plugins/git/.apm/skills/git-history/README.md index f37136b..72aaa3b 100644 --- a/plugins/git/.apm/skills/git-history/README.md +++ b/plugins/git/.apm/skills/git-history/README.md @@ -6,6 +6,10 @@ Inspect git history — log queries, bisect, and locating problematic commits. This skill handles history inspection within the git workflow suite. It queries logs with pickaxe/line-range/custom formats, runs bisect to find bug-introducing commits, and locates commits for downstream cherry-picking or reverting. It returns structured results for agent composition. Rebase, squash, fixup, and other history-rewriting operations are owned by git-commits, not this skill. +## Composition + +`git-branches` delegates cherry-pick and revert here (see `git-branches`'s `references/merging.md`), which is why this skill carries those two operations rather than treating them as out of scope. They are general git knowledge, not drawn from the `history-inspection.md` research corpus. Server-side commit history on a Gitea-hosted repository belongs to `gitea-branches`; this skill reads the local working copy. + ## Usage ``` @@ -19,6 +23,7 @@ Describe your history task: search logs, bisect for a regression, or locate a sp | File | Purpose | |------|---------| | `SKILL.md` | Skill instructions for agents | -| `references/git-log-format.md` | Full log format placeholders, diff-filter letters, `-L` syntax, ancestry filters, diff output-control flags | +| `references/bisect.md` | Loaded when the entry procedure is bisect: manual and automated flows, exit codes, skip, replay, narrowing, custom terms | +| `references/git-log-format.md` | Loaded when a log or diff flag needs looking up: format placeholders, presets, diff-filter letters, `-L` syntax, ancestry filters, pickaxe binary-file behaviour, diff output-control flags | | `references/sources.md` | Research sources and provenance | | `references/README.md` | Index of the references directory | diff --git a/plugins/git/.apm/skills/git-history/SKILL.md b/plugins/git/.apm/skills/git-history/SKILL.md index 9d05894..a4ab045 100644 --- a/plugins/git/.apm/skills/git-history/SKILL.md +++ b/plugins/git/.apm/skills/git-history/SKILL.md @@ -2,7 +2,10 @@ name: git-history description: > - Inspect git history: query logs with pickaxe, line-range, or custom formats; find bug origins via bisect; locate problematic commits for cherry-picking or reverting. Use when investigating history, tracing when a change happened, or finding the commit that broke something. Return structured results for downstream agents. Do not use for authoring or formatting commit messages, or executing rebase/squash/fixup operations — use git-commits for that. + Use when investigating git history — querying logs, tracing when a change + landed, bisecting the commit that broke something, or locating one to + revert or backport. Not authoring or rebasing commits -> `git-commits`. + Not history on a Gitea server -> `gitea-branches`. metadata: category: git @@ -16,81 +19,47 @@ allowed-tools: Bash ## Gotchas -- **Pickaxe searches (`-S` vs `-G`)**: `-S"string"` finds commits where string count changed; `-G"regex"` finds any line matching regex in diffs. They're not equivalent: a line replaced (one removal + one addition) matches `-G` but not `-S` if count is unchanged. -- **`--follow` only works for single files**: it traces renames but fails with multiple paths or directory globs. Use `git log -- ` or query without `--follow`. -- **Bisect with skips**: if bisect cannot pinpoint a commit because the culprit is adjacent to skipped commits, it reports "cannot find exact culprit" and lists candidates. This is not a failure — it's as precise as the skip range allows. -- **Interactive rebase is non-recoverable on mistake**: there's no undo once `rebase -i` starts. Suggest `git reflog` to recover if the user realizes mid-way they selected the wrong commits. -- **`-L` (line-range history) requires exact line numbers or regex patterns**: off-by-one errors omit the target range. Test the range with `git log -L` before offering it to users. +- `-S"string"` matches only where the string's *count* changed, so a line edited in place matches `-G"regex"` and not `-S`. Reach for `-G` whenever the string may have moved rather than appeared. +- `--follow` traces renames for exactly one path. Given several paths or a glob it fails instead of degrading, so run it once per file. +- Under `git bisect run`, exit `128` or above **aborts the session** rather than marking the commit bad, so a crashing test script ends the search silently. +- Bisect answering "cannot find exact culprit" beside skipped commits is a complete result: it is as precise as the skip range allows. -## Query Logs and Locate Commits +## Step 1 — Pick the entry procedure -Default to `git log --oneline` for quick inspection. For deeper queries: +| What is known | Procedure | +|---|---| +| Content, a file, or a line range to search for | Query the log — Step 2 | +| Nothing to search for — only that the behaviour changed between two points | Bisect — read `references/bisect.md` | +| The commit itself, already identified | Step 3 | -- **Find when a string appeared or disappeared**: Use `git log -S"string"` (count-sensitive, finds adds/removes). If you need any mention of the string in diffs, use `git log -G"regex"` instead. Add `--pickaxe-regex` to treat the `-S` string as a POSIX ERE, and `--pickaxe-all` to show every changed file in a matching changeset, not just the matching ones. Binary files are searched by `-S`; `-G` ignores them unless `--text` is also supplied. -- **Trace changes to a specific line or function**: Use `git log -L ,:` or `git log -L ::` (requires function name heuristic). This shows the evolution of that range across all commits. -- **Filter by change type**: Use `git log --diff-filter=` (A=added, M=modified, D=deleted, R=renamed) to narrow to specific file operations. -- **Mainline-only history through merges**: Use `--first-parent` to follow only the integration branch and skip merged-in side-branch commits; combine with `--merges`/`--no-merges` or `--ancestry-path`/`--min-parents`/`--max-parents` for other ancestry-graph filtering — see `references/git-log-format.md` for the full set. -- **Custom format for structured output**: Construct format string with `%h` (hash), `%s` (subject), `%an` (author), `%ar` (relative date), `%b` (body). Example: `git log --format="%h | %s | %an (%ar)"`. -- **File-specific history with renames**: Use `git log --follow -- ` (single file only). Without `--follow`, log stops at the rename boundary. +## Step 2 — Query the log -## Bisect to Find Blame Commit +Default to `git log --oneline`, then narrow by whatever is known: -Use bisect when hunting for the commit that introduced a bug or behaviour change. Binary search reduces iterations from O(N) to O(log N). +- **Content**: `git log -S"string"`, or `-G"regex"` to match any diff line. `--pickaxe-regex` makes the `-S` argument a POSIX ERE; `--pickaxe-all` shows every file in a matching changeset. +- **A line or function**: `git log -L ,:` or `git log -L ::`. Confirm the range resolves before reporting on it — an off-by-one silently omits the target. +- **A file across renames**: `git log --follow -- `. Without `--follow` the history stops at the rename boundary. +- **Mainline only**: `--first-parent` follows the integration branch and skips commits merged in from side branches. +- **Structured output**: `git log --format="%h | %s | %an (%ar)"`. -**Basic manual flow:** -```bash -git bisect start -git bisect bad [HEAD] # mark current (or specified) as broken -git bisect good # mark known-good baseline -# Git checks out midpoint; test it manually -git bisect good # if test passes -git bisect bad # if test fails -# Repeat until git reports "X is the first bad commit" -git bisect reset # return to original HEAD +If you need the placeholder catalogue, format presets, `--diff-filter` letters, full `-L` syntax, ancestry filters, pickaxe binary-file behaviour, or `git diff` output-control flags such as `--stat`, `--word-diff` and the whitespace options, read `references/git-log-format.md`. + +## Step 3 — Act on a located commit + +Offer the operation and its consequence; run it only once the user has chosen. + +- `git cherry-pick ` copies the commit's changes onto the current HEAD — for backporting a fix to another branch. +- `git revert ` adds a new commit undoing it — for un-applying merged work without rewriting history. +- `git blame ` attributes each line to the commit that last touched it, when the question is which commit introduced one specific line. + +For diff output control on the located commit, read `references/git-log-format.md`. + +## Step 4 — Return the result + +Report each located commit in this shape, so a calling agent can act on it without reparsing raw log output: + +```text + — + () +Recommendation: ``` - -**Automated with `git bisect run`:** if a test command exists, use `git bisect run `. Git interprets the exit code: `0`=good, `1-124`=bad, `125`=skip (build broken), `126-127`=POSIX shell errors treated as bad, `128+`=**aborts the bisect session entirely** (not treated as bad — a crashed test script can silently end the search). - -**With skip:** if a commit is untestable (broken build), use `git bisect skip` to exclude it without manually deciding good/bad. If the first-bad is adjacent to skips, bisect reports it cannot pinpoint but lists candidates. - -**Undoing a wrong good/bad call:** `git bisect log` prints the session's decision history; save it (`git bisect log > bisect.log`), edit out the mistaken entry, then `git bisect reset && git bisect replay bisect.log` to resume from the corrected log instead of restarting the whole search. - -**Narrowing and speeding up the search:** `git bisect start HEAD v1.2 -- src/` limits bisection to a path, cutting the number of trials. `--no-checkout` updates the `BISECT_HEAD` ref instead of checking out a working tree (useful for tests that don't need one; automatic in bare repos). `--first-parent` follows only first parents at merges, finding the integration commit that introduced a regression while ignoring broken side branches. - -**Inspecting remaining candidates visually:** `git bisect visualize` (alias `view`) opens the suspects in gitk; add `--stat` or `-p` to show diffstat or full patches instead. Falls back to `git log` when no graphical display is detected. - -**For non-regression hunts:** use `git bisect start --term-new --term-old ` to search for a property change instead of a bug (e.g., performance regression). Then use the custom terms instead of `good`/`bad`. - -For rebase execution (interactive rebase, squash/fixup/reword, conflict handling) see git-commits — it owns history-rewriting operations. This skill only locates commits and reports on history; it does not execute rebases. - -## Find and Manipulate Problematic Commits - -Once a commit is identified (via log query or bisect), offer cherry-pick or revert. This section is general git knowledge, not sourced from `history-inspection.md` — `git-branches`'s SKILL.md explicitly delegates cherry-pick/revert here (see its Merging section), which is why this skill carries them rather than treating them as out of scope: - -- **Cherry-pick**: `git cherry-pick ` copies a commit's changes onto current HEAD. Use when backporting fixes to other branches. -- **Revert**: `git revert ` creates a new commit that undoes the changes. Use when un-applying a merged commit without rewriting history. -- **Blame for context**: `git blame ` shows which commit last changed each line. Use to trace a specific line back to its introducing commit. - -## Inspect Diffs - -Diff-output tuning is in scope too: `--stat` for a diffstat summary, `--word-diff` for word-level (not line-level) changes, and whitespace flags (`-w`, `--ignore-blank-lines`) to suppress noise from reformatting. See `references/git-log-format.md` for the full flag set. - -## Return Results Structured - -For agent consumption, return: -- **Commit SHA** (full or abbreviated as appropriate) -- **Subject line** (from `%s`) -- **Author and date** (from `%an` and `%ar`) -- **Action taken or recommended** (e.g., "Found via bisect", "Offer cherry-pick to main", "Rebase conflicts detected") - -Example for agent: -``` -Found first bad commit: abc1234 -Subject: fix null pointer in parser -Author: Alice (2 weeks ago) -Recommendation: Backport to release branch via cherry-pick -``` - -## Reference - -For the full log format placeholder catalogue, named format presets, `--diff-filter` letters, `-L` range syntax, ancestry filters, and `git diff` output-control flags, read `references/git-log-format.md`. diff --git a/plugins/git/.apm/skills/git-history/references/README.md b/plugins/git/.apm/skills/git-history/references/README.md index 11fe328..c9a302a 100644 --- a/plugins/git/.apm/skills/git-history/references/README.md +++ b/plugins/git/.apm/skills/git-history/references/README.md @@ -12,4 +12,5 @@ This directory contains provenance metadata and research sources for the `git-hi ## Files - `sources.md` — Extracted research sources and their contributing documents -- `git-log-format.md` — Full `git log` format placeholder catalogue, named format presets, `--diff-filter` letters, `-L` line-range syntax, ancestry filters, and `git diff` output-control flags +- `bisect.md` — The full `git bisect` procedure: manual and automated flows, exit-code semantics, skip and replay, narrowing options, and custom good/bad terms +- `git-log-format.md` — Full `git log` format placeholder catalogue, named format presets, `--diff-filter` letters, `-L` line-range syntax, ancestry filters, pickaxe binary-file behaviour, and `git diff` output-control flags diff --git a/plugins/git/.apm/skills/git-history/references/bisect.md b/plugins/git/.apm/skills/git-history/references/bisect.md new file mode 100644 index 0000000..2fd7026 --- /dev/null +++ b/plugins/git/.apm/skills/git-history/references/bisect.md @@ -0,0 +1,68 @@ +--- +topic: bisect +source_keys: + - git-scm-bisect-docs +--- + +# Finding a commit with `git bisect` + +Read this when the question is *which commit changed the behaviour* and there is no string, file, +or line range to search the log for. Binary search reduces the trials from O(N) to O(log N). + +## Manual flow + +```bash +git bisect start +git bisect bad [HEAD] # mark current (or specified) as broken +git bisect good # mark known-good baseline +# Git checks out the midpoint; test it +git bisect good # test passes +git bisect bad # test fails +# Repeat until git reports "X is the first bad commit" +git bisect reset # return to the original HEAD +``` + +## Automated + +With a test command available, use `git bisect run `. Git reads the exit code: `0` good, +`1`–`124` bad, `125` skip (build broken), `126`–`127` POSIX shell errors, treated as bad, and +`128` or above aborts the session outright rather than marking the commit bad. + +## Untestable commits + +`git bisect skip` excludes a commit that cannot be built or tested without deciding good or bad +for it. When the first bad commit is adjacent to a skipped range, bisect reports that it cannot +pinpoint the culprit and lists the candidates — that is the precise answer the skip range allows, +not a failure. + +## Undoing a wrong good/bad call + +`git bisect log` prints the session's decision history. Save it, edit out the mistaken entry, and +resume from the corrected log rather than restarting the search: + +```bash +git bisect log > bisect.log +# edit bisect.log, removing the wrong decision +git bisect reset && git bisect replay bisect.log +``` + +## Narrowing and speeding up + +- `git bisect start HEAD v1.2 -- src/` restricts bisection to a path, cutting the trial count. +- `--no-checkout` updates the `BISECT_HEAD` ref instead of checking out a working tree — useful + for tests that do not need one, and automatic in bare repos. +- `--first-parent` follows only first parents at merges, finding the integration commit that + introduced a regression while ignoring broken side branches. + +## Inspecting the remaining candidates + +`git bisect visualize` (alias `view`) opens the suspects in gitk, falling back to `git log` when +no graphical display is detected. Add `--stat` or `-p` for a diffstat or full patches. + +## Hunting a non-bug property change + +`git bisect start --term-new --term-old ` searches for any property change — a +performance regression, say — instead of a bug. Use the custom terms in place of `good` and `bad` +for the rest of the session. + +Once the first bad commit is identified, return to Step 3 to act on it and Step 4 to report it. diff --git a/plugins/git/.apm/skills/git-history/references/git-log-format.md b/plugins/git/.apm/skills/git-history/references/git-log-format.md index 60e34d0..821bfdd 100644 --- a/plugins/git/.apm/skills/git-history/references/git-log-format.md +++ b/plugins/git/.apm/skills/git-history/references/git-log-format.md @@ -88,7 +88,7 @@ source_keys: | `%GK` | signing key ID | **Trailers:** -``` +```text %(trailers[:key=][,only][,separator=][,unfold][,keyonly][,valueonly]) ``` diff --git a/plugins/git/.apm/skills/git-history/references/sources.md b/plugins/git/.apm/skills/git-history/references/sources.md index 4b66a0f..fff5f45 100644 --- a/plugins/git/.apm/skills/git-history/references/sources.md +++ b/plugins/git/.apm/skills/git-history/references/sources.md @@ -12,7 +12,7 @@ Git bisect documentation covering binary search through commit history to find t - **Research doc:** plugins/git/docs/research/docs/git/history-inspection.md - **Doc heading:** `## git bisect` -- **Contributing files:** SKILL.md +- **Contributing files:** SKILL.md, references/bisect.md ## git-scm-log-docs @@ -28,4 +28,4 @@ Git diff documentation covering output control (--stat, --name-only, --name-stat - **Research doc:** plugins/git/docs/research/docs/git/history-inspection.md - **Doc heading:** `## git diff — Output Control` -- **Contributing files:** references/git-log-format.md +- **Contributing files:** SKILL.md, references/git-log-format.md diff --git a/plugins/git/skills/git-history/README.md b/plugins/git/skills/git-history/README.md index f37136b..72aaa3b 100644 --- a/plugins/git/skills/git-history/README.md +++ b/plugins/git/skills/git-history/README.md @@ -6,6 +6,10 @@ Inspect git history — log queries, bisect, and locating problematic commits. This skill handles history inspection within the git workflow suite. It queries logs with pickaxe/line-range/custom formats, runs bisect to find bug-introducing commits, and locates commits for downstream cherry-picking or reverting. It returns structured results for agent composition. Rebase, squash, fixup, and other history-rewriting operations are owned by git-commits, not this skill. +## Composition + +`git-branches` delegates cherry-pick and revert here (see `git-branches`'s `references/merging.md`), which is why this skill carries those two operations rather than treating them as out of scope. They are general git knowledge, not drawn from the `history-inspection.md` research corpus. Server-side commit history on a Gitea-hosted repository belongs to `gitea-branches`; this skill reads the local working copy. + ## Usage ``` @@ -19,6 +23,7 @@ Describe your history task: search logs, bisect for a regression, or locate a sp | File | Purpose | |------|---------| | `SKILL.md` | Skill instructions for agents | -| `references/git-log-format.md` | Full log format placeholders, diff-filter letters, `-L` syntax, ancestry filters, diff output-control flags | +| `references/bisect.md` | Loaded when the entry procedure is bisect: manual and automated flows, exit codes, skip, replay, narrowing, custom terms | +| `references/git-log-format.md` | Loaded when a log or diff flag needs looking up: format placeholders, presets, diff-filter letters, `-L` syntax, ancestry filters, pickaxe binary-file behaviour, diff output-control flags | | `references/sources.md` | Research sources and provenance | | `references/README.md` | Index of the references directory | diff --git a/plugins/git/skills/git-history/SKILL.md b/plugins/git/skills/git-history/SKILL.md index 9d05894..a4ab045 100644 --- a/plugins/git/skills/git-history/SKILL.md +++ b/plugins/git/skills/git-history/SKILL.md @@ -2,7 +2,10 @@ name: git-history description: > - Inspect git history: query logs with pickaxe, line-range, or custom formats; find bug origins via bisect; locate problematic commits for cherry-picking or reverting. Use when investigating history, tracing when a change happened, or finding the commit that broke something. Return structured results for downstream agents. Do not use for authoring or formatting commit messages, or executing rebase/squash/fixup operations — use git-commits for that. + Use when investigating git history — querying logs, tracing when a change + landed, bisecting the commit that broke something, or locating one to + revert or backport. Not authoring or rebasing commits -> `git-commits`. + Not history on a Gitea server -> `gitea-branches`. metadata: category: git @@ -16,81 +19,47 @@ allowed-tools: Bash ## Gotchas -- **Pickaxe searches (`-S` vs `-G`)**: `-S"string"` finds commits where string count changed; `-G"regex"` finds any line matching regex in diffs. They're not equivalent: a line replaced (one removal + one addition) matches `-G` but not `-S` if count is unchanged. -- **`--follow` only works for single files**: it traces renames but fails with multiple paths or directory globs. Use `git log -- ` or query without `--follow`. -- **Bisect with skips**: if bisect cannot pinpoint a commit because the culprit is adjacent to skipped commits, it reports "cannot find exact culprit" and lists candidates. This is not a failure — it's as precise as the skip range allows. -- **Interactive rebase is non-recoverable on mistake**: there's no undo once `rebase -i` starts. Suggest `git reflog` to recover if the user realizes mid-way they selected the wrong commits. -- **`-L` (line-range history) requires exact line numbers or regex patterns**: off-by-one errors omit the target range. Test the range with `git log -L` before offering it to users. +- `-S"string"` matches only where the string's *count* changed, so a line edited in place matches `-G"regex"` and not `-S`. Reach for `-G` whenever the string may have moved rather than appeared. +- `--follow` traces renames for exactly one path. Given several paths or a glob it fails instead of degrading, so run it once per file. +- Under `git bisect run`, exit `128` or above **aborts the session** rather than marking the commit bad, so a crashing test script ends the search silently. +- Bisect answering "cannot find exact culprit" beside skipped commits is a complete result: it is as precise as the skip range allows. -## Query Logs and Locate Commits +## Step 1 — Pick the entry procedure -Default to `git log --oneline` for quick inspection. For deeper queries: +| What is known | Procedure | +|---|---| +| Content, a file, or a line range to search for | Query the log — Step 2 | +| Nothing to search for — only that the behaviour changed between two points | Bisect — read `references/bisect.md` | +| The commit itself, already identified | Step 3 | -- **Find when a string appeared or disappeared**: Use `git log -S"string"` (count-sensitive, finds adds/removes). If you need any mention of the string in diffs, use `git log -G"regex"` instead. Add `--pickaxe-regex` to treat the `-S` string as a POSIX ERE, and `--pickaxe-all` to show every changed file in a matching changeset, not just the matching ones. Binary files are searched by `-S`; `-G` ignores them unless `--text` is also supplied. -- **Trace changes to a specific line or function**: Use `git log -L ,:` or `git log -L ::` (requires function name heuristic). This shows the evolution of that range across all commits. -- **Filter by change type**: Use `git log --diff-filter=` (A=added, M=modified, D=deleted, R=renamed) to narrow to specific file operations. -- **Mainline-only history through merges**: Use `--first-parent` to follow only the integration branch and skip merged-in side-branch commits; combine with `--merges`/`--no-merges` or `--ancestry-path`/`--min-parents`/`--max-parents` for other ancestry-graph filtering — see `references/git-log-format.md` for the full set. -- **Custom format for structured output**: Construct format string with `%h` (hash), `%s` (subject), `%an` (author), `%ar` (relative date), `%b` (body). Example: `git log --format="%h | %s | %an (%ar)"`. -- **File-specific history with renames**: Use `git log --follow -- ` (single file only). Without `--follow`, log stops at the rename boundary. +## Step 2 — Query the log -## Bisect to Find Blame Commit +Default to `git log --oneline`, then narrow by whatever is known: -Use bisect when hunting for the commit that introduced a bug or behaviour change. Binary search reduces iterations from O(N) to O(log N). +- **Content**: `git log -S"string"`, or `-G"regex"` to match any diff line. `--pickaxe-regex` makes the `-S` argument a POSIX ERE; `--pickaxe-all` shows every file in a matching changeset. +- **A line or function**: `git log -L ,:` or `git log -L ::`. Confirm the range resolves before reporting on it — an off-by-one silently omits the target. +- **A file across renames**: `git log --follow -- `. Without `--follow` the history stops at the rename boundary. +- **Mainline only**: `--first-parent` follows the integration branch and skips commits merged in from side branches. +- **Structured output**: `git log --format="%h | %s | %an (%ar)"`. -**Basic manual flow:** -```bash -git bisect start -git bisect bad [HEAD] # mark current (or specified) as broken -git bisect good # mark known-good baseline -# Git checks out midpoint; test it manually -git bisect good # if test passes -git bisect bad # if test fails -# Repeat until git reports "X is the first bad commit" -git bisect reset # return to original HEAD +If you need the placeholder catalogue, format presets, `--diff-filter` letters, full `-L` syntax, ancestry filters, pickaxe binary-file behaviour, or `git diff` output-control flags such as `--stat`, `--word-diff` and the whitespace options, read `references/git-log-format.md`. + +## Step 3 — Act on a located commit + +Offer the operation and its consequence; run it only once the user has chosen. + +- `git cherry-pick ` copies the commit's changes onto the current HEAD — for backporting a fix to another branch. +- `git revert ` adds a new commit undoing it — for un-applying merged work without rewriting history. +- `git blame ` attributes each line to the commit that last touched it, when the question is which commit introduced one specific line. + +For diff output control on the located commit, read `references/git-log-format.md`. + +## Step 4 — Return the result + +Report each located commit in this shape, so a calling agent can act on it without reparsing raw log output: + +```text + — + () +Recommendation: ``` - -**Automated with `git bisect run`:** if a test command exists, use `git bisect run `. Git interprets the exit code: `0`=good, `1-124`=bad, `125`=skip (build broken), `126-127`=POSIX shell errors treated as bad, `128+`=**aborts the bisect session entirely** (not treated as bad — a crashed test script can silently end the search). - -**With skip:** if a commit is untestable (broken build), use `git bisect skip` to exclude it without manually deciding good/bad. If the first-bad is adjacent to skips, bisect reports it cannot pinpoint but lists candidates. - -**Undoing a wrong good/bad call:** `git bisect log` prints the session's decision history; save it (`git bisect log > bisect.log`), edit out the mistaken entry, then `git bisect reset && git bisect replay bisect.log` to resume from the corrected log instead of restarting the whole search. - -**Narrowing and speeding up the search:** `git bisect start HEAD v1.2 -- src/` limits bisection to a path, cutting the number of trials. `--no-checkout` updates the `BISECT_HEAD` ref instead of checking out a working tree (useful for tests that don't need one; automatic in bare repos). `--first-parent` follows only first parents at merges, finding the integration commit that introduced a regression while ignoring broken side branches. - -**Inspecting remaining candidates visually:** `git bisect visualize` (alias `view`) opens the suspects in gitk; add `--stat` or `-p` to show diffstat or full patches instead. Falls back to `git log` when no graphical display is detected. - -**For non-regression hunts:** use `git bisect start --term-new --term-old ` to search for a property change instead of a bug (e.g., performance regression). Then use the custom terms instead of `good`/`bad`. - -For rebase execution (interactive rebase, squash/fixup/reword, conflict handling) see git-commits — it owns history-rewriting operations. This skill only locates commits and reports on history; it does not execute rebases. - -## Find and Manipulate Problematic Commits - -Once a commit is identified (via log query or bisect), offer cherry-pick or revert. This section is general git knowledge, not sourced from `history-inspection.md` — `git-branches`'s SKILL.md explicitly delegates cherry-pick/revert here (see its Merging section), which is why this skill carries them rather than treating them as out of scope: - -- **Cherry-pick**: `git cherry-pick ` copies a commit's changes onto current HEAD. Use when backporting fixes to other branches. -- **Revert**: `git revert ` creates a new commit that undoes the changes. Use when un-applying a merged commit without rewriting history. -- **Blame for context**: `git blame ` shows which commit last changed each line. Use to trace a specific line back to its introducing commit. - -## Inspect Diffs - -Diff-output tuning is in scope too: `--stat` for a diffstat summary, `--word-diff` for word-level (not line-level) changes, and whitespace flags (`-w`, `--ignore-blank-lines`) to suppress noise from reformatting. See `references/git-log-format.md` for the full flag set. - -## Return Results Structured - -For agent consumption, return: -- **Commit SHA** (full or abbreviated as appropriate) -- **Subject line** (from `%s`) -- **Author and date** (from `%an` and `%ar`) -- **Action taken or recommended** (e.g., "Found via bisect", "Offer cherry-pick to main", "Rebase conflicts detected") - -Example for agent: -``` -Found first bad commit: abc1234 -Subject: fix null pointer in parser -Author: Alice (2 weeks ago) -Recommendation: Backport to release branch via cherry-pick -``` - -## Reference - -For the full log format placeholder catalogue, named format presets, `--diff-filter` letters, `-L` range syntax, ancestry filters, and `git diff` output-control flags, read `references/git-log-format.md`. diff --git a/plugins/git/skills/git-history/references/README.md b/plugins/git/skills/git-history/references/README.md index 11fe328..c9a302a 100644 --- a/plugins/git/skills/git-history/references/README.md +++ b/plugins/git/skills/git-history/references/README.md @@ -12,4 +12,5 @@ This directory contains provenance metadata and research sources for the `git-hi ## Files - `sources.md` — Extracted research sources and their contributing documents -- `git-log-format.md` — Full `git log` format placeholder catalogue, named format presets, `--diff-filter` letters, `-L` line-range syntax, ancestry filters, and `git diff` output-control flags +- `bisect.md` — The full `git bisect` procedure: manual and automated flows, exit-code semantics, skip and replay, narrowing options, and custom good/bad terms +- `git-log-format.md` — Full `git log` format placeholder catalogue, named format presets, `--diff-filter` letters, `-L` line-range syntax, ancestry filters, pickaxe binary-file behaviour, and `git diff` output-control flags diff --git a/plugins/git/skills/git-history/references/bisect.md b/plugins/git/skills/git-history/references/bisect.md new file mode 100644 index 0000000..2fd7026 --- /dev/null +++ b/plugins/git/skills/git-history/references/bisect.md @@ -0,0 +1,68 @@ +--- +topic: bisect +source_keys: + - git-scm-bisect-docs +--- + +# Finding a commit with `git bisect` + +Read this when the question is *which commit changed the behaviour* and there is no string, file, +or line range to search the log for. Binary search reduces the trials from O(N) to O(log N). + +## Manual flow + +```bash +git bisect start +git bisect bad [HEAD] # mark current (or specified) as broken +git bisect good # mark known-good baseline +# Git checks out the midpoint; test it +git bisect good # test passes +git bisect bad # test fails +# Repeat until git reports "X is the first bad commit" +git bisect reset # return to the original HEAD +``` + +## Automated + +With a test command available, use `git bisect run `. Git reads the exit code: `0` good, +`1`–`124` bad, `125` skip (build broken), `126`–`127` POSIX shell errors, treated as bad, and +`128` or above aborts the session outright rather than marking the commit bad. + +## Untestable commits + +`git bisect skip` excludes a commit that cannot be built or tested without deciding good or bad +for it. When the first bad commit is adjacent to a skipped range, bisect reports that it cannot +pinpoint the culprit and lists the candidates — that is the precise answer the skip range allows, +not a failure. + +## Undoing a wrong good/bad call + +`git bisect log` prints the session's decision history. Save it, edit out the mistaken entry, and +resume from the corrected log rather than restarting the search: + +```bash +git bisect log > bisect.log +# edit bisect.log, removing the wrong decision +git bisect reset && git bisect replay bisect.log +``` + +## Narrowing and speeding up + +- `git bisect start HEAD v1.2 -- src/` restricts bisection to a path, cutting the trial count. +- `--no-checkout` updates the `BISECT_HEAD` ref instead of checking out a working tree — useful + for tests that do not need one, and automatic in bare repos. +- `--first-parent` follows only first parents at merges, finding the integration commit that + introduced a regression while ignoring broken side branches. + +## Inspecting the remaining candidates + +`git bisect visualize` (alias `view`) opens the suspects in gitk, falling back to `git log` when +no graphical display is detected. Add `--stat` or `-p` for a diffstat or full patches. + +## Hunting a non-bug property change + +`git bisect start --term-new --term-old ` searches for any property change — a +performance regression, say — instead of a bug. Use the custom terms in place of `good` and `bad` +for the rest of the session. + +Once the first bad commit is identified, return to Step 3 to act on it and Step 4 to report it. diff --git a/plugins/git/skills/git-history/references/git-log-format.md b/plugins/git/skills/git-history/references/git-log-format.md index 60e34d0..821bfdd 100644 --- a/plugins/git/skills/git-history/references/git-log-format.md +++ b/plugins/git/skills/git-history/references/git-log-format.md @@ -88,7 +88,7 @@ source_keys: | `%GK` | signing key ID | **Trailers:** -``` +```text %(trailers[:key=][,only][,separator=][,unfold][,keyonly][,valueonly]) ``` diff --git a/plugins/git/skills/git-history/references/sources.md b/plugins/git/skills/git-history/references/sources.md index 4b66a0f..fff5f45 100644 --- a/plugins/git/skills/git-history/references/sources.md +++ b/plugins/git/skills/git-history/references/sources.md @@ -12,7 +12,7 @@ Git bisect documentation covering binary search through commit history to find t - **Research doc:** plugins/git/docs/research/docs/git/history-inspection.md - **Doc heading:** `## git bisect` -- **Contributing files:** SKILL.md +- **Contributing files:** SKILL.md, references/bisect.md ## git-scm-log-docs @@ -28,4 +28,4 @@ Git diff documentation covering output control (--stat, --name-only, --name-stat - **Research doc:** plugins/git/docs/research/docs/git/history-inspection.md - **Doc heading:** `## git diff — Output Control` -- **Contributing files:** references/git-log-format.md +- **Contributing files:** SKILL.md, references/git-log-format.md