Snapshot what generate writes, from packages loaded in memory by crhntr · Pull Request #151 · typelate/muxt

crhntr · 2026-09-14T23:42:51Z

internal/load/loadtest type checks a package in memory against the official standard library's export data. internal/generate/testdata holds 32 txtar snapshots of generated files, each with its configuration inline, and runs in milliseconds.

Part 6 of 8, stacked on #150. Replaces #145.

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https://claude.ai/code/session_01UjkpA4fvZ7xQAsY65Beprp

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🟡 Changes recommended

Three unresolved moderate issues remain in nested-call handling and in-memory loader behavior.

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Pull request overview

Adds in-memory package loading and generator snapshot coverage, including standard-library resolution and hydration tests.

Changes:

Adds loadtest utilities for in-memory type checking.
Adds loader, hydration, configuration, and generated-file tests.
Adds 32 generator snapshots and documents the testing workflow.

File summaries

File	Summary / review notes
`internal/load/stdlib_test.go`	Tests standard-library type resolution.
`internal/load/loadtest/loadtest.go`	Adds the in-memory package loader. Moderate (2 votes): export-cache paths containing spaces are parsed incorrectly. Moderate (1 vote): subdirectory embedded assets are omitted.
`internal/load/loadtest/loadtest_test.go`	Tests template loading through the loader.
`internal/load/hydrate_test.go`	Tests configuration hydration behavior.
`internal/generate/testdata/synthesized_method_note.txtar`	Snapshot for synthesized method notes.
`internal/generate/testdata/status_codes.txtar`	Status-code generation snapshot.
`internal/generate/testdata/sse.txtar`	SSE generation snapshot.
`internal/generate/testdata/sse_messages_without_datastar.txtar`	SSE message validation snapshot.
`internal/generate/testdata/sse_datastar.txtar`	Datastar SSE snapshot.
`internal/generate/testdata/route_without_call.txtar`	Route-without-call snapshot.
`internal/generate/testdata/result_shapes.txtar`	Result-shape snapshot.
`internal/generate/testdata/response_argument.txtar`	Response-argument snapshot.
`internal/generate/testdata/request_body.txtar`	Request-body snapshot.
`internal/generate/testdata/redirect.txtar`	Redirect snapshot.
`internal/generate/testdata/receiver_method_sets.txtar`	Receiver method-set snapshot.
`internal/generate/testdata/path_parameter_types.txtar`	Path-parameter snapshot.
`internal/generate/testdata/nested_calls.txtar`	Nested-call snapshot. Moderate (2 votes): nested calls execute after invalid argument parsing and should be skipped.
`internal/generate/testdata/multipart.txtar`	Multipart snapshot.
`internal/generate/testdata/marshal_json.txtar`	JSON-marshaling snapshot.
`internal/generate/testdata/last_event_id.txtar`	Last-event-ID snapshot.
`internal/generate/testdata/inferred_methods.txtar`	Inferred-method snapshot.
`internal/generate/testdata/form_values.txtar`	Form-values snapshot.
`internal/generate/testdata/form_struct.txtar`	Form-struct snapshot.
`internal/generate/testdata/flag_without_muxt_version.txtar`	Version-omission snapshot.
`internal/generate/testdata/flag_unexported_identifiers.txtar`	Unexported-identifier snapshot.
`internal/generate/testdata/flag_multiple_files.txtar`	Multiple-file output snapshot.
`internal/generate/testdata/flag_logger_path_prefix_middleware.txtar`	Logger, prefix, and middleware snapshot.
`internal/generate/testdata/flag_htmx.txtar`	HTMX output snapshot.
`internal/generate/testdata/flag_custom_names.txtar`	Custom-name configuration snapshot.
`internal/generate/testdata/execute_callback.txtar`	Execute-callback snapshot.
`internal/generate/testdata/err_signals_without_datastar.txtar`	Datastar validation-error snapshot.
`internal/generate/testdata/err_route_paths_method_collision.txtar`	Route-path collision snapshot.
`internal/generate/testdata/err_response_state_with_response_argument.txtar`	Response-state error snapshot.
`internal/generate/testdata/err_resolution.txtar`	Resolution-error snapshot.
`internal/generate/testdata/err_name_errors.txtar`	Template-name error snapshot.
`internal/generate/testdata/err_duplicate_pattern.txtar`	Duplicate-route error snapshot.
`internal/generate/snapshot_test.go`	Implements snapshot generation and comparison.
`internal/generate/generated_test.go`	Tests generated-file argument discovery.
`internal/cli/configurations_test.go`	Tests parsed command configurations.
`CLAUDE.md`	Documents the snapshot testing workflow.

Review details

Files not reviewed (1)

internal/generate/generated_test.go: Generated file

Suppressed comments (1)

internal/load/loadtest/loadtest.go:163

Subdirectory assets are written but omitted from EmbedFiles, so a fixture using //go:embed partials/*.gohtml cannot be hydrated: check.LoadTemplates will not see the matched template even though go/packages would report it. Keep only root .go files in goPaths, but add non-Go files from subdirectories to embedded, and cover this case in loadtest_test.go.

Files reviewed: 40/41 changed files
Comments generated: 2
Review effort level: Lite

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🔵 Needs a closer look

Two moderate review findings remain unresolved.

Review details

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internal/generate/generated_test.go: Generated file

Suppressed comments (2)

internal/generate/snapshot_test.go:95

When a want/<name> file is empty and the generator omits that output, both map lookups yield "", so this comparison treats the missing file as equal and the snapshot passes. Compare map presence as well as content so missing generated files are detected.

				if got[name] != want[name] {

internal/load/loadtest/loadtest.go:165

Package is documented as modeling a normal load.Packages result, but this classification puts every root *.go file into GoFiles, including _test.go. A fixture containing tests will therefore type-check test declarations as part of the production package (and can change or break the loaded API), unlike packages.Load with Tests unset; exclude test files from goPaths while still writing them if needed.

Files reviewed: 40/41 changed files
Comments generated: 0 new
Review effort level: Lite

generate's own tests covered a few percent of it: what a handler looks like for a form struct, an sse route, a status code in the name or a redirect in the template was only stated by the integration suite, which compiles and runs every scratch module and takes over a minute. internal/load/loadtest builds what a package load returns without loading the package graph: it writes the files, type checks them in memory, and imports the official standard library from the export data go list reports for it, reading it with gcexportdata -- as go/packages does -- and giving each package the imports go list reports, which is how check finds fmt behind html/template. The standard library is whichever the go command in use provides. A test binary pays a few hundred milliseconds once to read it. TestStandardLibrary states load.StandardLibrary's answers against it, and TestHydration the order load's hydration reports a missing package, a missing receiver and a variable that does not evaluate. internal/generate/testdata/generate/*.txtar holds one case per feature: the receiver's Go source, the templates, and the files and log lines generation produces. An archive holds the configuration it generates with, in its own config.json, beside the command line that parses into it; nothing outside the archive says what a case is. The directory an archive is in names the command, so a case runs alone as -run TestSnapshots/generate/sse. Reading it is encoding/json/v2, which the module now asks for Go 1.27 to have. TestSnapshots loads the case through loadtest and load.GenerateSource, as muxt generate does, generates, and compares; the 32 cases cover most of the package. It also fails on a generated file that imports a package it does not use. go test -run TestSnapshots -update rewrites the want/ files, and the diff is the review. A snapshot says what the generator does, not that the result compiles or serves requests; that stays the integration suite's job. Assisted-by: Claude:claude-opus-5 gofumpt

…mory muxt check is the command the integration suite runs most, and its reports -- a field the data type lacks, a template nothing renders, a route waiting for muxt generate -- were only stated there, behind a package load per script. internal/analysis/testdata/<command>/*.txtar holds cases for check, the route listing, and the template caller and call listings. The directory an archive is in names the command it runs, so a case runs alone as -run TestSnapshots/list-template-calls/calls, and the archive holds the configuration it runs with, in its own config.json, beside the command line that parses into it. A listing's configuration needs nothing to read as JSON: regexp.Regexp writes itself as the text it was compiled from, and internal/configjson says the rest -- a field the command line left alone is null rather than an empty list, and a member a configuration does not declare is an error. TestSnapshots loads the case through loadtest and internal/load's hydration, as the commands do, and compares what the analysis reports. Assisted-by: Claude:claude-opus-5 gofumpt

The mutation run's planning -- which templates each ExecuteTemplate call reaches, with what dot, and which variations apply -- read the loaded templates, the checker built on them, and the syntax trees it searched for the string literal a template was written in. So stating any of it took a module on disk and the go command. Planning now runs on an input: the source.Package internal/load reads. loadInput builds one with the go command; planFrom and revisionOf read nothing else. A template's string literal is found by parsing its file's text, which planning already holds, instead of searching the loader's syntax trees. With that, nothing reads load.Templates, and it goes. internal/mutation/testdata/test-template-mutations/*.txtar snapshots a dry run's report for ten cases -- a literal template, partials and trims, a template pattern, skipped mutants, the operand budget, other delimiters, a --diff revision, and the errors a plan returns -- each loaded through loadtest and planned in milliseconds. An archive holds the configuration it plans with, in its own config.json: regexp.Regexp writes itself as the text it was compiled from, so a pattern reads as the command line wrote it, and a pattern the command line left alone is null -- "" would be a pattern matching everything. As in the other two suites, the directory names the command, so a case runs alone as -run TestSnapshots/test-template-mutations/diff. CLAUDE.md's recipes for a feature, a bug and an error now start from the unit test at the layer that owns the behavior, and say what the in-memory loader cannot stand in for. Assisted-by: Claude:claude-opus-5 gofumpt

The snapshot archives hold the configuration they run with, and reading one is encoding/json/v2: it knows how to read a *regexp.Regexp, which v1 could only do through a second struct carrying the pattern's source. Everywhere else muxt reads or writes JSON went with it, so one library answers "how does muxt read JSON": the module list, the overlay each mutant is delivered through, the generated file's import map, and a command's --format=json result. Two differences the standard library documents, and the integration suite insisted on: - omitempty in v2 omits an empty JSON value -- null, "", [], {} -- and no longer a zero number or a false. The fields that meant the latter say omitzero now, so a mutant that took no measurable time still reports no seconds, and a module listing still leaves out the flags a package does not set. - Reading is case sensitive, and a member the target does not declare is an error rather than silence. Every name muxt reads was already written by muxt or by the go command, so nothing had to change. - Writing makes no promise about map order, writes a nil list or map as [] or {}, and escapes neither <, >, & nor U+2028 and U+2029, where v1 sorted map keys, wrote null and escaped them. --format=json is read by scripts, so it is written with the options that say v1's choices, and TestWriteResultJSON states each one. A listing's import map now writes through the encoder it is handed (MarshalJSONTo), so those options reach it too, rather than a separate Marshal deciding its order. The reports and listings are byte for byte what they were. Assisted-by: Claude:claude-opus-5 gofumpt

A few loops spelled out what the slices and maps packages already name: gathering a map's keys and sorting them, asking whether a list holds something, copying a list, and a union of keys de-duplicated by hand. - slices.Sorted(maps.Keys(m)) where keys were gathered and then sorted: the module listing's directories, muxttest.Check's file names, and the template source files generation walks. sort is no longer imported anywhere in muxt's own code. - slices.ContainsFunc where a loop or an IndexFunc whose index went unused only asked whether something is there: marshalJSON refusing the execute callback, and a receiver method already in the interface. - slices.Clone for File.ImportSpecs' copy; its callers only range over the result or take its length. - sortedKeys in the generate snapshot harness appends every map's keys, sorts and compacts, rather than checking Contains before each append. Loops that find an element to change in place, build a different type, or return early with more than a yes or no stay as they were. Every generated file and report is unchanged. Assisted-by: Claude:claude-opus-5 gofumpt

Copilot AI lite review requested due to automatic review settings September 14, 2026 23:42

This was referenced Sep 14, 2026

Snapshot the template checks and listings, from packages loaded in memory #152

Merged

Isolate packages.Load behind internal/load #145

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Copilot started reviewing on behalf of crhntr September 14, 2026 23:43 View session

Copilot AI reviewed Sep 14, 2026

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Comment thread internal/generate/testdata/generate/nested_calls.txtar

Comment thread internal/load/loadtest/loadtest.go

crhntr mentioned this pull request Sep 16, 2026

generate --output-multiple-files panics on a template with no file #156

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crhntr force-pushed the split/5-command-configurations branch from d562b63 to 9f9dc50 Compare September 16, 2026 01:36

crhntr force-pushed the split/6-generate-snapshots branch from 28f15b7 to 2b9cff3 Compare September 16, 2026 01:36

crhntr force-pushed the split/5-command-configurations branch from 9f9dc50 to a822bf1 Compare September 16, 2026 06:07

crhntr force-pushed the split/6-generate-snapshots branch 2 times, most recently from 21633ce to aebc4d8 Compare September 16, 2026 06:22

crhntr force-pushed the split/5-command-configurations branch from a822bf1 to 0deba16 Compare September 16, 2026 06:22

crhntr requested a lite review from Copilot September 16, 2026 06:23

Copilot started reviewing on behalf of crhntr September 16, 2026 06:23 View session

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crhntr force-pushed the split/6-generate-snapshots branch from aebc4d8 to ed2e17c Compare September 16, 2026 06:38

crhntr force-pushed the split/5-command-configurations branch 2 times, most recently from cc7dcfb to c575f80 Compare September 16, 2026 06:42

crhntr force-pushed the split/6-generate-snapshots branch 2 times, most recently from 452e06d to 2a89249 Compare September 16, 2026 06:58

crhntr force-pushed the split/5-command-configurations branch 2 times, most recently from da4e93d to 336b576 Compare September 16, 2026 07:26

crhntr force-pushed the split/6-generate-snapshots branch 3 times, most recently from 8c594b8 to e0bb019 Compare September 16, 2026 20:30

crhntr force-pushed the split/6-generate-snapshots branch from e0bb019 to 8f20fbf Compare September 16, 2026 22:07

crhntr added 3 commits September 16, 2026 16:32

crhntr mentioned this pull request Sep 16, 2026

Say it with slices and maps #160

Merged

crhntr merged commit 34652fb into split/5-command-configurations Sep 17, 2026

crhntr deleted the split/6-generate-snapshots branch September 17, 2026 15:58

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Snapshot what generate writes, from packages loaded in memory - #151

Snapshot what generate writes, from packages loaded in memory#151
crhntr merged 5 commits into
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crhntr commented Sep 14, 2026

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