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// Tests that the aggregate command can use command-level let variables with $merge. Note $merge
// tests must be run in a noPassthrough suite so the other operators are exercised in
// jstests/core/command_let_variables.js.
// @tags: [requires_fcv46]
(function() {
"use strict";
const coll = db.command_let_variables;
const targetColl = db.command_let_variables_target;
coll.drop();
assert.commandWorked(coll.insert([
{
Species: "Blackbird (Turdus merula)",
population_trends: [
{term: {start: 1970, end: 2014}, pct_change: -16, annual: -0.38, trend: "no change"},
{term: {start: 2009, end: 2014}, pct_change: -2, annual: -0.36, trend: "no change"}
]
},
{
Species: "Bullfinch (Pyrrhula pyrrhula)",
population_trends: [
{term: {start: 1970, end: 2014}, pct_change: -39, annual: -1.13, trend: "no change"},
{term: {start: 2009, end: 2014}, pct_change: 12, annual: 2.38, trend: "weak increase"}
]
},
{
Species: "Chaffinch (Fringilla coelebs)",
population_trends: [
{term: {start: 1970, end: 2014}, pct_change: 27, annual: 0.55, trend: "no change"},
{term: {start: 2009, end: 2014}, pct_change: -7, annual: -1.49, trend: "weak decline"}
]
},
{
Species: "Song Thrush (Turdus philomelos)",
population_trends: [
{term: {start: 1970, end: 2014}, pct_change: -53, annual: -1.7, trend: "weak decline"},
{term: {start: 2009, end: 2014}, pct_change: -4, annual: -0.88, trend: "no change"}
]
}
]));
// Function to prepare target collection of $merge stage for testing.
function prepMergeTargetColl() {
targetColl.drop();
assert.commandWorked(db.runCommand({
aggregate: coll.getName(),
pipeline: [
{$match: {$expr: {$eq: ["$Species", "Song Thrush (Turdus philomelos)"]}}},
{$out: targetColl.getName()}
],
cursor: {}
}));
}
// Test that $merge stage can use 'let' variables within its own stage's pipeline.
prepMergeTargetColl();
assert.commandWorked(db.runCommand({
aggregate: coll.getName(),
pipeline: [{
$merge: {
into: targetColl.getName(),
let : {variable: "INNER"},
whenMatched: [{$addFields: {"var": "$$variable"}}]
}
}],
cursor: {}
}));
assert.eq(targetColl.aggregate({$match: {$expr: {$eq: ["$var", "INNER"]}}}).toArray().length, 1);
// Test that $merge stage can access command-level 'let' variables.
prepMergeTargetColl();
assert.commandWorked(db.runCommand({
aggregate: coll.getName(),
pipeline: [
{$merge: {into: targetColl.getName(), whenMatched: [{$addFields: {"var": "$$variable"}}]}}
],
cursor: {},
let : {variable: "OUTER"}
}));
assert.eq(targetColl.aggregate({$match: {$expr: {$eq: ["$var", "OUTER"]}}}).toArray().length, 1);
// Test that $merge stage can use stage-level and command-level 'let' variables in same command.
prepMergeTargetColl();
assert.commandWorked(db.runCommand({
aggregate: coll.getName(),
pipeline: [{
$merge: {
into: targetColl.getName(),
let : {stage: "INNER"},
whenMatched: [{$addFields: {"innerVar": "$$stage", "outerVar": "$$command"}}]
}
}],
cursor: {},
let : {command: "OUTER"}
}));
assert.eq(
targetColl
.aggregate({
$match: {
$and:
[{$expr: {$eq: ["$innerVar", "INNER"]}},
{$expr: {$eq: ["$outerVar", "OUTER"]}}]
}
})
.toArray()
.length,
1);
// Test that $merge stage follows variable scoping rules with stage-level and command-level 'let'
// variables.
prepMergeTargetColl();
assert.commandWorked(db.runCommand({
aggregate: coll.getName(),
pipeline: [{
$merge: {
into: targetColl.getName(),
let : {variable: "INNER"},
whenMatched: [{$addFields: {"var": "$$variable"}}]
}
}],
cursor: {},
let : {variable: "OUTER"}
}));
assert.eq(targetColl.aggregate({$match: {$expr: {$eq: ["$var", "INNER"]}}}).toArray().length, 1);
// Test that expressions wrapped with $literal are serialized correctly in combination with
// pipelines containing $merge.
prepMergeTargetColl();
assert.commandWorked(db.runCommand({
aggregate: coll.getName(),
pipeline: [{$project: {var : "$$variable"}}, {$merge: {into: targetColl.getName()}}],
let : {variable: {$literal: "$notAFieldPath"}},
cursor: {}
}));
assert.eq(targetColl.aggregate({$match: {$expr: {$eq: ["$var", {$literal: "$notAFieldPath"}]}}})
.toArray()
.length,
4);
prepMergeTargetColl();
assert.commandWorked(db.runCommand({
aggregate: coll.getName(),
pipeline: [{
$merge: {
into: targetColl.getName(),
let : {variable: {$literal: "$notAFieldPath"}},
whenMatched: [{$addFields: {"var": "$$variable"}}]
}
}],
cursor: {},
}));
assert.eq(targetColl.aggregate({$match: {$expr: {$eq: ["$var", {$literal: "$notAFieldPath"}]}}})
.toArray()
.length,
1);
}());
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