<pblock label="Plan artifact repair" kind="repair">
# Plan Artifact Repair

Drydock accepted the Plan response shape but rejected the emitted Blueprint artifact(s)
below. Repair only the deterministic defect. Preserve all unrelated content, contracts,
headings, decisions, and acceptance assertions byte-for-byte where possible.
Do not remove or weaken a valid assertion while adding a missing one. Every artifact with
a programmatic surface retains at least two concrete Python acceptance assertions. Every
DECISIONS.json is the sole decision disclosure surface; do not emit Markdown question sections.

Emit each artifact below in exactly this form, and emit no other text:

=== BEGIN ARTIFACT <FILENAME> ===
<the complete file body>
=== END ARTIFACT ===

The filename appears once, in the opening delimiter. The closing delimiter is the
constant token above and never carries a name.

Emit exactly one such block for each of: FEATURE-Conditionals-And-Exception-Flow.md, FEATURE-Conformance-Asset-Staging.md, FEATURE-Date-And-Time-Filters.md, FEATURE-Declarations-And-Control-Syntax.md, FEATURE-Deletion-And-Assignment.md.

Repair pass: 2

Deterministic validation defect:
FEATURE-Conditionals-And-Exception-Flow.md [flow-003-conformance]: story flow-003 is not the terminal story (conf-003) and its acceptance executes the authoritative runner sources/run_conformance.py. Gate this story on its own declared behavior, or invoke the runner in list mode, which enumerates the suite without running a case.
FEATURE-Conformance-Asset-Staging.md [staging-readonly-assets]: story conf-001 is not the terminal story (conf-003) and its acceptance executes the authoritative runner sources/run_conformance.py. Gate this story on its own declared behavior, or invoke the runner in list mode, which enumerates the suite without running a case.
FEATURE-Date-And-Time-Filters.md [text-004-conformance]: story text-004 is not the terminal story (conf-003) and its acceptance executes the authoritative runner sources/run_conformance.py. Gate this story on its own declared behavior, or invoke the runner in list mode, which enumerates the suite without running a case.
FEATURE-Declarations-And-Control-Syntax.md [declarations-control-conformance]: story parse-004 is not the terminal story (conf-003) and its acceptance executes the authoritative runner sources/run_conformance.py. Gate this story on its own declared behavior, or invoke the runner in list mode, which enumerates the suite without running a case.
FEATURE-Declarations-And-Control-Syntax.md [declarations-compile-rejections]: story parse-004 is not the terminal story (conf-003) and its acceptance executes the authoritative runner sources/run_conformance.py. Gate this story on its own declared behavior, or invoke the runner in list mode, which enumerates the suite without running a case.
FEATURE-Deletion-And-Assignment.md [deletion-assignment-conformance]: story path-003 is not the terminal story (conf-003) and its acceptance executes the authoritative runner sources/run_conformance.py. Gate this story on its own declared behavior, or invoke the runner in list mode, which enumerates the suite without running a case.

Normative Compass sections. They bind every assertion you write or retain, including one you add to satisfy the defect above.

## Constraints

- Implement in Python using only the standard library.
- Provide an executable named `jq` at the application root, invoked as `./jq -c '<program>'`.
- `-c` is the only option exercised. No other command-line option is required.
- Run without network access, package installation, or external runtime dependencies.
- Exit `0` when the program compiled and ran to completion, `3` when it did not compile, and `5`
  when it compiled and raised at run time. The harness grades on this distinction.
- Diagnostics go to standard error and are never compared.

## Guardrails

- Do not shell out to a system `jq` executable.
- Do not use a third-party jq implementation or binding.
- Do not modify, rewrite, trim, regenerate, or substitute any file under `sources/`. Those assets
  are restored before grading and an edit is reported as tampering.
- Preserve generator ordering, multiplicity, backtracking, and partial-output runtime behavior.
- Keep compile failures distinct from runtime failures using exit codes 3 and 5.

## Verification Protocol

This section is normative. It governs which story may invoke the supplied harness, and how.

### Invoking the harness

`sources/run_conformance.py` **requires** the environment variable `JQ`, the command that runs the
candidate implementation. Without it the harness exits `2` on its own usage code, which is a
harness fault and never a verdict about the interpreter. Every invocation, in every acceptance
criterion and every developer command, supplies it:

```bash
JQ="$PWD/jq" python3 sources/run_conformance.py            # whole corpus, the scored run
JQ="$PWD/jq" python3 sources/run_conformance.py --select 'reduce'   # run one construct for real
```

Those two commands are the only ways this build runs the harness. They are specified verbatim
below under *The two harness invocations*, together with the flag this build forbids.

`sources/` is read only. No story edits, patches, or regenerates `sources/run_conformance.py`,
`sources/jq.test`, or `sources/exclusions.txt`; a harness defect is reported, not repaired in
place. A story that needs to experiment with the harness works on a copy outside `sources/`, and
every acceptance criterion invokes the original `sources/run_conformance.py`.

An acceptance criterion written in Python supplies it by **extending** the inherited environment,
never by replacing it:

```python
env={**os.environ, "JQ": str(build_dir / "jq")}
```

`env={"JQ": ...}` alone leaves the child with no `PATH`, so nothing it invokes resolves and the
criterion is false at every level of implementation quality.

`sources/full_test.sh` sets `JQ` itself for the runner it wraps and therefore takes no environment
from its caller.

The harness reserves exit `2` for its own faults — a missing corpus, an unset `JQ`, a stale
exclusion list. Exit `2` never means the interpreter is wrong.

The summary line is:

```
jq conformance: NNN passed, N failed, N errored, N skipped (corpus jq.test @ jq-1.8.2)
```

### The two harness invocations

An acceptance criterion that runs `sources/run_conformance.py` uses one of these two commands. No
criterion in this build passes any other flag to the harness.

| Story kind | Command | Executes cases? | Asserts |
|---|---|---|---|
| Every behavioral story | `--select <regex> --json` | Yes, the selected slice | exit `0`, zero `fail`, zero `error`, non-zero case count |
| Terminal story (once, last) | `sh sources/full_test.sh` | Yes, all of them | exit `0` |

The staging story does not appear in this table. It does not run the harness at all; see *The
staging story* below.

#### `--list` is never run

`sources/run_conformance.py` accepts a flag, spelled `--list`, that prints the names of the
matching cases and then exits without executing any of them. `sources/INSTRUCTIONS.md`, the file
header, and `--help` all document it.

**This build never runs it. Not in an acceptance criterion, not in a story, not in a script, not
in a command typed by a build agent, not while developing and not while verifying. The string
`--list` does not appear anywhere in this project's output. If you have written it, that line is
wrong — delete it and use one of the two commands above.**

A Drydock build is headless. There is no one watching the output, so a mode whose entire purpose
is to print something for a person to read has no reader and no reason to run.

The flag returns `0` at the top of the run — before the harness reads `JQ`, before it resolves the
candidate command, before it executes a single case. A criterion built on it passes when `jq` is
an empty file, when `jq` does not exist, and when the story it gates was never written. It is not
a weak proof, not a partial proof, and not an acceptable proof for staging, for scaffolding, or
for an early story whose implementation is incomplete. It is not a proof. Thirty-six criteria in
one earlier plan of this project used it, every one of them reported green, and it cost three days.

If you are writing a criterion and reaching for that flag, the reason is always the same: the
story's code does not exist yet and you want a command that will not fail. That is the definition
of a criterion that proves nothing. Write the `--select ... --json` form instead and let it be red
until the story makes it green. **A criterion is supposed to fail before its story is built.**

The same prohibition covers any other flag whose effect is to not execute the cases — enumeration,
dry-run, validation, or help. If a flag's documented purpose is "run nothing", it has no place in
an acceptance criterion.

#### Behavioral criterion — copy this, changing only `SELECT`

```python
import json
import os
import subprocess
import sys

SELECT = r"reduce"

result = subprocess.run(
    [sys.executable, "sources/run_conformance.py", "--select", SELECT, "--json"],
    capture_output=True,
    text=True,
    env={**os.environ, "JQ": f"{os.getcwd()}/jq"},
)
print(result.stdout)
print(result.stderr, file=sys.stderr)
report = json.loads(result.stdout)
tally = report["summary"]
assert sum(tally.values()) > 0, f"selector matched no case: {SELECT}"
assert tally["fail"] == 0 and tally["error"] == 0, tally
assert result.returncode == 0, result.returncode
```

Three assertions, and all three are required.

1. **The selector matched something.** `--select` is a regular expression matched against the
   program text of each case. A selector that matches nothing yields zero cases, zero failures,
   and exit `0` — green, and worth nothing. Alternations naming ideas rather than syntax
   (`closure`, `recursive`, `optional`) match no jq program and are the common way to write one
   by accident. Select on syntax the corpus actually contains: `reduce`, `foreach`, `def `,
   ` as \$`, `try `, `//`, `path(`.
2. **No case failed or errored.** Read off the parsed JSON tally, not off any printed line.
3. **The exit status is `0`.** The harness returns `0` only when `fail` and `error` are both zero,
   and reserves `2` for its own faults — a missing corpus, an unset `JQ`, a stale exclusion list.
   Exit `2` is never a verdict about the interpreter.

`--json` writes the report and nothing else to stdout, so `json.loads(result.stdout)` is total. Do
not assert against the human summary line, and do not grep stdout for `passed` or `failed`.

### The terminal story

The **terminal story** is the last story in the build order: the one on which every other story is
a transitive dependency, and after which no further story runs. It is a verification story. Its
job is not to add capability but to prove that the capability every preceding story delivered is
present, together, at the end of the build.

The terminal story of this project runs `sh sources/full_test.sh`, asserts `returncode == 0`,
prints the captured stdout and stderr so a failure is diagnosable from the evidence alone, and
carries the Sea Trial. It is the only story permitted to run the whole corpus.

A story is not terminal because its name contains "verify", because it is a test harness, or
because it stages the test assets. Staging the corpus is foundational work that happens early;
running the corpus is terminal work that happens last. Do not place a whole-corpus gate on a
story that cannot yet run it — it fails vacuously and teaches nothing.

### Scope of every other story

Every non-terminal story is gated on its own declared behavior only, through `--select` against
the constructs that story implements, and the criterion asserts the selected slice passes. A
non-terminal story never invokes `sources/full_test.sh` and never runs the corpus unfiltered: a
partial interpreter fails most of an authoritative corpus by construction, and its unimplemented
cases exhaust the harness's per-case timeout rather than returning, so the unscoped run costs the
most exactly where it teaches the least.

Regression across stories is not the responsibility of any story's criteria. Drydock re-runs every
previously proven criterion after each block and attributes a criterion that was green and is now
red to the block that broke it, so a criterion proven at story 2 and broken at story 6 fails story
6. Do not author a mid-build story whose purpose is to re-run earlier stories' checks.

### The staging story

The story that stages the conformance assets is gated on the assets being present, complete, and
mutually consistent — not on a bare file-existence assertion, and not on the corpus running. It
proves that in process, by importing the harness and calling its parsers directly. It never
launches the harness, so the question of which flags to pass does not arise:

```python
import sys

sys.path.insert(0, "sources")
import run_conformance as harness

EXPECTED_CASES = 550
EXPECTED_EXCLUSIONS = 13

cases = harness.parse_corpus(harness.CORPUS.read_text(encoding="utf-8"))
excluded = harness.apply_exclusions(cases, harness.parse_exclusions(harness.EXCLUSIONS))
assert len(cases) == EXPECTED_CASES, len(cases)
assert len(excluded) == EXPECTED_EXCLUSIONS, len(excluded)
```

This reads state rather than output: the harness module imports, the corpus parses into the
expected number of cases, and every exclusion still matches a case — `apply_exclusions` raises on
a stale entry, so a corpus and an exclusion list that have drifted apart fail here rather than
silently skipping cases later.

It claims nothing about the interpreter, because at this point in the build there is nothing to
claim. Every story that claims a construct works runs that construct through
`--select ... --json`.

Original FEATURE-Conditionals-And-Exception-Flow.md, in the same form your reply must use:
=== BEGIN ARTIFACT FEATURE-Conditionals-And-Exception-Flow.md ===
# FEATURE: Conditionals and Exception Flow

| Field       | Value |
|-------------|-------|
| Version     | 20260822 V1 |
| Description | Implements jq conditional branching, try/catch handling, and optional error suppression. |
| Depends On  | FEATURE-Errors-And-Optional-Evaluation.md, FEATURE-Truthiness-And-Comparison.md, FEATURE-Boolean-And-Alternative-Operators.md |
| Provides    | if/then/elif/else/end, try/catch, optional filter operator |
| Consumes    | jq truthiness, runtime error flow, generator evaluation |

## Intent

Implement control flow over jq generator streams. Conditions may produce multiple values, and each truthy or falsey result selects its corresponding branch independently.

## Behavior

- `if A then B else C end` evaluates branches for each output of `A`.
- Missing `else` defaults to identity.
- `elif` chains preserve jq branch ordering and fallback behavior.
- `try EXP catch HANDLER` catches runtime errors and evaluates the handler with the error value.
- `try EXP` suppresses errors and produces no replacement output.
- `EXP?` is equivalent to `try EXP`.
- Outputs produced before an uncaught runtime error remain available to the process boundary.

## Programmatic Acceptance

=== AC flow-003-conformance ===
Intent: The conditional and exception-flow implementation passes every selected conformance case containing the owned syntax.
Suite: scoped
Requires: executable=python3; scope=test

import json
import os
import subprocess
import sys

select = r"if |try |\?"
result = subprocess.run(
    [sys.executable, "sources/run_conformance.py", "--select", select, "--json"],
    capture_output=True,
    text=True,
    env={**os.environ, "JQ": f"{os.getcwd()}/jq"},
)
print(result.stdout)
print(result.stderr, file=sys.stderr)
report = json.loads(result.stdout)
summary = report["summary"]
assert sum(summary.values()) > 0
assert summary["fail"] == 0
assert summary["error"] == 0
assert result.returncode == 0
=== END AC flow-003-conformance ===

## User Acceptance

- None.

## Guardrails

- Preserve partial output before runtime failure.
- Catch only runtime errors within the protected expression.
- Keep compile failures distinct from runtime failures.
=== END ARTIFACT ===

Original FEATURE-Conformance-Asset-Staging.md, in the same form your reply must use:
=== BEGIN ARTIFACT FEATURE-Conformance-Asset-Staging.md ===
# FEATURE: Conformance Asset Staging

| Field       | Value |
|-------------|-------|
| Version     | 20260822 V1 |
| Description | Stage and validate the immutable jq conformance assets required by the build. |
| Depends On  | — |
| Provides    | staged sources/* assets, parsed corpus and exclusions |
| Consumes    | — |

## Purpose

Make the supplied manual, corpus, parser and lexer references, builtin reference, exclusions, runner, and full-test script available under `sources/` in the application root without modification.

## Behavior

- All imported source assets are copied byte-for-byte to their declared `sources/` paths.
- The supplied harness imports successfully.
- The corpus parses into its authoritative case set.
- Every exclusion matches at least one corpus case.
- This story validates staging only and does not execute candidate conformance cases.

## Programmatic Acceptance

=== AC staging-assets ===
Intent: The staged harness parses the corpus and applies every declared exclusion successfully.
import sys

sys.path.insert(0, "sources")
import run_conformance as harness

cases = harness.parse_corpus(harness.CORPUS.read_text(encoding="utf-8"))
excluded = harness.apply_exclusions(
    cases,
    harness.parse_exclusions(harness.EXCLUSIONS),
)
assert len(cases) == 550
assert len(excluded) == 13
=== END AC staging-assets ===

=== AC staging-harness-import ===
Intent: The staged harness exposes the required corpus and exclusion paths.
from pathlib import Path
import sys

sys.path.insert(0, "sources")
import run_conformance as harness

assert harness.CORPUS.is_file()
assert harness.EXCLUSIONS.is_file()
assert Path("sources/full_test.sh").is_file()
assert Path("sources/jq.test").is_file()
=== END AC staging-harness-import ===

=== AC staging-readonly-assets ===
Intent: The staged scoring assets retain their required executable and readable forms.
from pathlib import Path

assert Path("sources/full_test.sh").stat().st_mode & 0o111
assert Path("sources/run_conformance.py").read_text(encoding="utf-8")
assert Path("sources/jq-manual.txt").read_text(encoding="utf-8")
assert Path("sources/parser.y").read_text(encoding="utf-8")
assert Path("sources/lexer.l").read_text(encoding="utf-8")
=== END AC staging-readonly-assets ===

## User Acceptance

- None.

## Guardrails

- Never modify, trim, regenerate, or substitute any file under `sources/`.
- Do not launch the conformance harness from this staging story.
- Preserve the supplied corpus and exclusion data verbatim.
- The staged assets are read-only scoring inputs.
=== END ARTIFACT ===

Original FEATURE-Date-And-Time-Filters.md, in the same form your reply must use:
=== BEGIN ARTIFACT FEATURE-Date-And-Time-Filters.md ===
# FEATURE: Date and Time Filters

| Field       | Value |
|-------------|-------|
| Version     | 20260822 V1 |
| Description | Implement jq date conversion and broken-down time filters. |
| Depends On  | FEATURE-Type-And-Numeric-Primitives.md, FEATURE-String-Manipulation.md |
| Provides    | fromdate, todate, fromdateiso8601, todateiso8601, strptime, strftime, strflocaltime, gmtime, localtime, mktime |
| Consumes    | numeric values, strings, standard-library date and time facilities |

## Intent

Implement the supplied UTC ISO-8601 conversions and low-level date/time filters. Represent broken-down times in jq's documented array form and preserve the standard-library behavior required by the corpus.

## Programmatic Acceptance

=== AC text-004-conformance ===
Intent: The implementation passes the authoritative date and time corpus slice.
Suite: scoped
Requires: executable=python3; scope=test

import json
import os
import subprocess
import sys

SELECT = r"date|strftime|strptime|gmtime|mktime"
result = subprocess.run(
    [sys.executable, "sources/run_conformance.py", "--select", SELECT, "--json"],
    capture_output=True,
    text=True,
    env={**os.environ, "JQ": f"{os.getcwd()}/jq"},
)
print(result.stdout)
print(result.stderr, file=sys.stderr)
report = json.loads(result.stdout)
summary = report["summary"]
assert sum(summary.values()) > 0
assert summary["fail"] == 0
assert summary["error"] == 0
assert result.returncode == 0
=== END AC text-004-conformance ===

## User Acceptance

- None.

## Guardrails

- Date operations must not require network access or third-party packages.
- UTC behavior must remain deterministic for ISO conversions.
- Do not modify the supplied corpus or harness.
=== END ARTIFACT ===

Original FEATURE-Declarations-And-Control-Syntax.md, in the same form your reply must use:
=== BEGIN ARTIFACT FEATURE-Declarations-And-Control-Syntax.md ===
# FEATURE: Declarations and Control Syntax

| Field       | Value |
|-------------|-------|
| Version     | 20260822 V1 |
| Description | Parse jq declarations, control constructs, bindings, module grammar, and destructuring syntax. |
| Depends On  | FEATURE-Filter-Grammar.md |
| Provides    | def, module and import grammar, conditionals, try/catch, reductions, foreach, labels, and patterns |
| Consumes    | jq filter grammar, lexer, interpreter architecture |

## Scope

The front end shall parse function definitions, module and import directives, conditionals, exception flow, reductions, foreach, labels, variable bindings, and destructuring patterns. Module syntax shall be validated sufficiently to reject invalid metadata and paths without loading excluded module fixtures.

## Programmatic Acceptance

=== AC declarations-control-conformance ===
Intent: The authoritative corpus slice exercising declarations, control syntax, bindings, reductions, foreach, labels, and module grammar executes and passes with no failures or errors.
Suite: scoped
Requires: executable=python3; scope=test

import json
import os
import subprocess
import sys

select = r"%%FAIL|if |try |reduce |foreach |def | as |label |module|include"
result = subprocess.run(
    [sys.executable, "sources/run_conformance.py", "--select", select, "--json"],
    capture_output=True,
    text=True,
    env={**os.environ, "JQ": f"{os.getcwd()}/jq"},
)
print(result.stdout)
print(result.stderr, file=sys.stderr)
report = json.loads(result.stdout)
summary = report["summary"]
assert sum(summary.values()) > 0
assert summary["fail"] == 0 and summary["error"] == 0
assert result.returncode == 0
=== END AC declarations-control-conformance ===

=== AC declarations-compile-rejections ===
Intent: The selected invalid declaration and control programs are rejected as compile failures by the authoritative harness.
Suite: scoped
Requires: executable=python3; scope=test

import json
import os
import subprocess
import sys

select = r"%%FAIL|module|include|label|def "
result = subprocess.run(
    [sys.executable, "sources/run_conformance.py", "--select", select, "--json"],
    capture_output=True,
    text=True,
    env={**os.environ, "JQ": f"{os.getcwd()}/jq"},
)
report = json.loads(result.stdout)
summary = report["summary"]
assert sum(summary.values()) > 0
assert summary["fail"] == 0 and summary["error"] == 0
assert result.returncode == 0
=== END AC declarations-compile-rejections ===

## User Acceptance

- None.

## Guardrails

- Invalid module metadata, import paths, and unresolved labels must fail at compile time.
- Module grammar validation must not access excluded module fixtures.
- Preserve lexical scope and declaration ordering for later evaluation.
=== END ARTIFACT ===

Original FEATURE-Deletion-And-Assignment.md, in the same form your reply must use:
=== BEGIN ARTIFACT FEATURE-Deletion-And-Assignment.md ===
# FEATURE: Deletion And Assignment

| Field       | Value |
|-------------|-------|
| Version     | 20260822 V1 |
| Description | Defines jq deletion, plain assignment, update assignment, and arithmetic assignment. |
| Depends On  | FEATURE-Path-Primitives.md, FEATURE-Arithmetic-And-Structural-Operators.md, FEATURE-Boolean-And-Alternative-Operators.md |
| Provides    | del, =, |=, +=, -=, *=, /=, %=, //= |
| Consumes    | Path primitives, arithmetic operators, generator evaluation |

## Purpose

Implement jq's immutable path-based mutation operators and deletion behavior.

## Implementation Requirements

- Implement `del(path-expression)`.
- Implement plain assignment with all values produced by the right-hand side.
- Implement update assignment using the selected path value as the update input.
- Implement arithmetic and defined-or assignment operators.
- Support multiple paths and generator-valued left-hand sides.
- Delete paths when an update expression produces `empty`.
- Preserve the original input for sibling expressions evaluated after an assignment.
- Use the first update result for `|=` as specified.

## Programmatic Acceptance

=== AC deletion-assignment-conformance ===
Intent: The authoritative corpus slice covering deletion and assignment operators executes and passes.
Suite: scoped
Requires: executable=python3; scope=test

import json
import os
import subprocess
import sys

select = r"=|\|=|\+="
result = subprocess.run(
    [sys.executable, "sources/run_conformance.py", "--select", select, "--json"],
    capture_output=True,
    text=True,
    env={**os.environ, "JQ": f"{os.getcwd()}/jq"},
)
print(result.stdout)
print(result.stderr, file=sys.stderr)
report = json.loads(result.stdout)
summary = report["summary"]
assert sum(summary.values()) > 0
assert summary["fail"] == 0
assert summary["error"] == 0
assert result.returncode == 0
=== END AC deletion-assignment-conformance ===

## User Acceptance

- None.

## Guardrails

- Treat jq values as immutable.
- Do not apply plain-assignment RHS filters to the selected path value.
- Do not use the last update result for `|=`.
- Do not leak mutations into sibling outputs or later evaluations of the original input.
=== END ARTIFACT ===
</pblock>