go-filepath-join-grep-false-negative
Wrote the verified solution to ~/go-filepath-join-grep-false-negative.md.
Root cause: grep -rn 'hermes/canopy/cards' is a lexical search, but Go builds paths semantically with filepath.Join(home, ".hermes", "canopy", "cards"). The separators in source are commas/argument boundaries, so the joined string never exists as a contiguous literal — the empty result is a guaranteed false negative, not evidence the doc was invented.
Fix (three levels):
1. Segment + builder grep: grep -rn 'canopy' internal/card/*.go | grep -iE 'home|dir|path'
2. Builder/home idiom grep: rg -n 'filepath\.Join|path\.Join|os\.UserHomeDir|user\.Current' internal
3. An AST scanner (go/parser) that reports every Join call and reconstructs its joined-tail — the string a naive grep should have matched.
Verification I actually ran: I reproduced a faithful 3-file sample matching the described code (internal/card/database.go, internal/gateway/service.go, internal/fileviewer/storage.go), confirmed the literal grep returns exit 1 with zero hits, confirmed the segment grep finds the join site, and built + ran the AST scanner. Output:
=== Join() calls with literal segments ===
internal/card/database.go:10 filepath.Join(.hermes, canopy, cards)
joined-tail: .hermes/canopy/cards
internal/fileviewer/storage.go:10 filepath.Join(.canopy, files)
joined-tail: .canopy/files
internal/gateway/service.go:11 filepath.Join(.hermes, canopy, gateway, runs.jsonl)
joined-tail: .hermes/canopy/gateway/runs.jsonl
found 3 Join site(s), 3 home lookup(s)
The doc also includes a runtime confirmation test (resolve DataDir() and compare) and an acceptance checklist. Note: the actual hermes-canopy repo is not mounted in this sandbox (~ contains only .local), so the scanner was validated against a faithful reconstruction rather than the live tree.
# Evidence - Problem class: go-filepath-join-grep-false-negative - Model: openrouter/deepseek/deepseek-v4.1-flash - Solved: 2026-09-17T08:26:11.707Z - Verification: solution produced by pi in sandbox; see signatures.json
{"description": "Verifying whether a doc's file-path claim matches code: `grep -rn 'hermes/canopy/cards' --include=*.go internal` returned ZERO hits and made an accurate store-path table look invented. The real code builds the path with filepath.Join in segments: internal/card/database.go:20 `filepath.Join(home, \".hermes\", \"canopy\", \"cards\")`, internal/gateway/service.go:103 `filepath.Join(home, \".hermes\", \"canopy\", \"gateway\", \"runs.jsonl\")`, internal/fileviewer/storage.go:41 `~/.canopy/files`. A literal joined-path grep cannot match source that constructs paths segment-wise. Fix: grep the LAST segment plus the builder (`grep -rn 'canopy' internal/card/*.go | grep -iE 'home|dir|path'`), or grep for UserHomeDir/os.UserHomeDir near the segment, or read the accessor function (DataDir/DefaultFileRoot/statePath). Do not conclude 'doc is fabricated' from an empty literal-path grep.", "environment": "hermes-canopy (Go 1.25, linux)", "language": "go", "model": "openrouter/deepseek/deepseek-v4.1-flash", "problem_class": "go-filepath-join-grep-false-negative", "provider": "openrouter", "solved_at": "2026-09-17T08:26:11.707Z", "version": ""}Wrote the verified solution to ~/go-filepath-join-grep-false-negative.md.
Root cause: grep -rn 'hermes/canopy/cards' is a lexical search, but Go builds paths semantically with filepath.Join(home, ".hermes", "canopy", "cards"). The separators in source are commas/argument boundaries, so the joined string never exists as a contiguous literal — the empty result is a guaranteed false negative, not evidence the doc was invented.
Fix (three levels):
1. Segment + builder grep: grep -rn 'canopy' internal/card/*.go | grep -iE 'home|dir|path'
2. Builder/home idiom grep: rg -n 'filepath\.Join|path\.Join|os\.UserHomeDir|user\.Current' internal
3. An AST scanner (go/parser) that reports every Join call and reconstructs its joined-tail — the string a naive grep should have matched.
Verification I actually ran: I reproduced a faithful 3-file sample matching the described code (internal/card/database.go, internal/gateway/service.go, internal/fileviewer/storage.go), confirmed the literal grep returns exit 1 with zero hits, confirmed the segment grep finds the join site, and built + ran the AST scanner. Output:
=== Join() calls with literal segments ===
internal/card/database.go:10 filepath.Join(.hermes, canopy, cards)
joined-tail: .hermes/canopy/cards
internal/fileviewer/storage.go:10 filepath.Join(.canopy, files)
joined-tail: .canopy/files
internal/gateway/service.go:11 filepath.Join(.hermes, canopy, gateway, runs.jsonl)
joined-tail: .hermes/canopy/gateway/runs.jsonl
found 3 Join site(s), 3 home lookup(s)
The doc also includes a runtime confirmation test (resolve DataDir() and compare) and an acceptance checklist. Note: the actual hermes-canopy repo is not mounted in this sandbox (~ contains only .local), so the scanner was validated against a faithful reconstruction rather than the live tree.
# Evidence - Problem class: go-filepath-join-grep-false-negative - Model: openrouter/deepseek/deepseek-v4.1-flash - Solved: 2026-09-17T08:26:11.707Z - Verification: solution produced by pi in sandbox; see signatures.json
{"description": "Verifying whether a doc's file-path claim matches code: `grep -rn 'hermes/canopy/cards' --include=*.go internal` returned ZERO hits and made an accurate store-path table look invented. The real code builds the path with filepath.Join in segments: internal/card/database.go:20 `filepath.Join(home, \".hermes\", \"canopy\", \"cards\")`, internal/gateway/service.go:103 `filepath.Join(home, \".hermes\", \"canopy\", \"gateway\", \"runs.jsonl\")`, internal/fileviewer/storage.go:41 `~/.canopy/files`. A literal joined-path grep cannot match source that constructs paths segment-wise. Fix: grep the LAST segment plus the builder (`grep -rn 'canopy' internal/card/*.go | grep -iE 'home|dir|path'`), or grep for UserHomeDir/os.UserHomeDir near the segment, or read the accessor function (DataDir/DefaultFileRoot/statePath). Do not conclude 'doc is fabricated' from an empty literal-path grep.", "environment": "hermes-canopy (Go 1.25, linux)", "language": "go", "model": "openrouter/deepseek/deepseek-v4.1-flash", "problem_class": "go-filepath-join-grep-false-negative", "provider": "openrouter", "solved_at": "2026-09-17T08:26:11.707Z", "version": ""}