freeform-summary-to-galaxy-interface

---
type: research
subtype: component
title: "Galaxy collection semantics"
tags:
  - research/component
  - target/galaxy
status: draft
created: 2026-04-30
revised: 2026-05-05
revision: 3
ai_generated: false
related_notes:
  - "[[galaxy-xsd]]"
  - "[[galaxy-collection-tools]]"
  - "[[galaxy-apply-rules-dsl]]"
  - "[[nextflow-to-galaxy-channel-shape-mapping]]"
  - "[[nextflow-operators-to-galaxy-collection-recipes]]"
  - "[[galaxy-tool-job-failure-reference]]"
  - "[[galaxy-workflow-invocation-failure-reference]]"
  - "[[iwc-transformations-survey]]"
  - "[[galaxy-discover-datasets]]"
sources:
  - "https://github.com/galaxyproject/galaxy/blob/7765fae934fbfdee77e3be5f5b235e43735273ae/lib/galaxy/model/dataset_collections/types/collection_semantics.yml"
companions:
  - "galaxy-collection-semantics.yml"
  - "galaxy-collection-semantics.upstream.myst"
summary: "Vendored formal spec of Galaxy dataset-collection mapping/reduction semantics, with labeled examples and pinned test references."
---

> **Vendored from upstream**, pinned at SHA `7765fae`. Two files live next to this note:
>
> - `galaxy-collection-semantics.yml` — the structured source. **Agents and casting should consume this.** It carries the `tests:` blocks that pin concrete Galaxy test names; the rendered upstream view drops them.
> - `galaxy-collection-semantics.upstream.myst` — Galaxy's auto-generated MyST/LaTeX rendering of the YAML, vendored only so the human view below has something to render. Sync is manual.
>
> **When to consult:** authoring or reasoning about Molds and patterns that touch `data_collection` inputs, map-over / reduction shape changes, sub-collection mapping, `paired_or_unpaired`, or `sample_sheet`.

```vendored-myst
file: galaxy-collection-semantics.upstream.myst
source: https://github.com/g
...

# Collection Semantics

This document describes the semantics around working with Galaxy dataset collections.
In particular it describes how they operate within Galaxy tools and workflows.

:::{admonition} You Probably Don't Need to Read This
:class: caution

Any significantly sophisticated workflow language will have ways to collect data
into arrays or vectors or dictionaries and apply operations across this data (mapping)
or reduce the dimensionality of this data (reductions). Typically, this is explicitly
annotated with map functions or for loops. Galaxy however is designed to be a point
and click interface for connecting steps and running tools. It is important that steps
just connect and just do the most natural thing - and this is what Galaxy does.
This document just provides a mathematical formalism to that "what should just
intuitively work" that can be used to document test cases and help with implementation.
This is reference documentation not user documentation, Galaxy should just work.
:::

## Mapping

If a tool consumes a simple dataset parameter and produces a simple dataset parameter,
then any collection type may be "mapped over" the data input to that tool. The result of
that is the tool being applied to each element of the collection and "implicit collections"
being created from the outputs that are produced from those operations. Those implicit
collections have the same element identifiers in the same order as the input collection that is
mapped over. Each element of the implicit collections correspond to their own job and
Galaxy very naturally and intuitively parallelizes jobs without extra work from the user
and without any knowledge of the tool.


(BASIC_MAPPING_PAIRED)=
(BASIC_MAPPING_PAIRED_OR_UNPAIRED_PAIRED)=
(BASIC_MAPPING_PAIRED_OR_UNPAIRED_UN
...

- doc: |
    # Collection Semantics

    This document describes the semantics around working with Galaxy dataset collections.
    In particular it describes how they operate within Galaxy tools and workflows.

    :::{admonition} You Probably Don't Need to Read This
    :class: caution

    Any significantly sophisticated workflow language will have ways to collect data
    into arrays or vectors or dictionaries and apply operations across this data (mapping)
    or reduce the dimensionality of this data (reductions). Typically, this is explicitly
    annotated with map functions or for loops. Galaxy however is designed to be a point
    and click interface for connecting steps and running tools. It is important that steps
    just connect and just do the most natural thing - and this is what Galaxy does.
    This document just provides a mathematical formalism to that "what should just
    intuitively work" that can be used to document test cases and help with implementation.
    This is reference documentation not user documentation, Galaxy should just work.
    :::

    ## Mapping

    If a tool consumes a simple dataset parameter and produces a simple dataset parameter,
    then any collection type may be "mapped over" the data input to that tool. The result of
    that is the tool being applied to each element of the collection and "implicit collections"
    being created from the outputs that are produced from those operations. Those implicit
    collections have the same element identifiers in the same order as the input collection that is
    mapped over. Each element of the implicit collections correspond to their own job and
    Galaxy very naturally and intuitively parallelizes jobs without extra work from the user
    and without any knowledge of the tool.

...

---
type: research
subtype: component
title: "Galaxy sample_sheet collection types"
tags:
  - research/component
  - target/galaxy
status: draft
created: 2026-05-05
revised: 2026-05-06
revision: 2
ai_generated: true
related_notes:
  - "[[galaxy-collection-semantics]]"
  - "[[galaxy-collection-tools]]"
  - "[[nextflow-workflow-io-semantics]]"
  - "[[nextflow-params-to-galaxy-inputs]]"
  - "[[nextflow-path-glob-to-galaxy-datatype]]"
  - "[[nextflow-to-galaxy-channel-shape-mapping]]"
  - "[[nextflow-to-galaxy-reference-data-mapping]]"
related_molds:
  - "[[nextflow-summary-to-galaxy-interface]]"
  - "[[nextflow-summary-to-galaxy-data-flow]]"
sources:
  - "Galaxy PR #19305 (Implement Sample Sheets), merged 2025-07-30"
  - "lib/galaxy/model/dataset_collections/types/sample_sheet.py"
  - "lib/galaxy/model/dataset_collections/types/sample_sheet_util.py"
  - "lib/galaxy/model/dataset_collections/type_description.py"
  - "lib/galaxy/schema/schema.py (SampleSheetColumnDefinition, SampleSheetRow)"
  - "lib/galaxy/tools/wrappers.py (DatasetCollectionWrapper.sample_sheet_row)"
  - "lib/galaxy/tools/sample_sheet_to_tabular.xml"
  - "lib/galaxy/webapps/galaxy/api/dataset_collections.py (sample_sheet_workbook endpoints)"
  - "lib/galaxy/model/migrations/alembic/versions_gxy/3af58c192752_implement_sample_sheets.py"
summary: "Galaxy's sample_sheet collection family: typed column metadata, four variants, mapping rules, validator allowlist."
---

# Galaxy sample_sheet collection types

Reference for the Galaxy backend shape that targets structured per-row metadata — the natural landing zone for Nextflow `samplesheetToList` parameters and for any source-side idiom that pairs typed metadata columns with dataset references.

## Shape

A `sample_sheet` is a list-shaped collection where each el
...

---
type: research
subtype: component
tags:
  - research/component
  - target/galaxy
status: draft
created: 2026-05-03
revised: 2026-05-06
revision: 2
ai_generated: true
related_notes:
  - "[[iwc-workflow-testability-survey]]"
  - "[[iwc-test-data-conventions]]"
  - "[[planemo-asserts-idioms]]"
  - "[[iwc-shortcuts-anti-patterns]]"
  - "[[planemo-workflow-test-architecture]]"
  - "[[implement-galaxy-workflow-test]]"
  - "[[gxformat2-schema]]"
  - "[[gxformat2-workflow-inputs]]"
  - "[[galaxy-datatypes-conf]]"
summary: "Design guidance for Galaxy workflow inputs, outputs, and checkpoints that make IWC-style workflow tests possible."
---

# Galaxy workflow testability design

Use this note when authoring or translating a Galaxy workflow **before** the `-tests.yml` file exists. It covers workflow structure choices that make later IWC-style tests meaningful: labels, promoted checkpoints, collection identifiers, and fixture-compatible inputs.

This is not a `content/patterns/` page. It is cross-cutting design guidance for Molds that need testable Galaxy workflows. Assertion syntax lives in [[planemo-asserts-idioms]]. Test YAML fixture shapes live in [[iwc-test-data-conventions]]. Accepted shortcut vs smell calls live in [[iwc-shortcuts-anti-patterns]]. Corpus evidence trail lives in [[iwc-workflow-testability-survey]].

## 1. Treat labels as API

Workflow input and output labels are not cosmetic. Planemo and IWC tests address workflow inputs and outputs by label, and the survey found exact label matches for every asserted output across 114 matched workflow/test pairs. A generated workflow should therefore pick stable, descriptive labels before test authoring starts.

Rules:

- Label every output that may need a test assertion.
- Treat input/output renames as breaking changes
...