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module Bundler::PubGrub
class FailureWriter
def initialize(root)
@root = root
# { Incompatibility => Integer }
@derivations = {}
# [ [ String, Integer or nil ] ]
@lines = []
# { Incompatibility => Integer }
@line_numbers = {}
count_derivations(root)
end
def write
return @root.to_s unless @root.conflict?
visit(@root)
padding = @line_numbers.empty? ? 0 : "(#{@line_numbers.values.last}) ".length
@lines.map do |message, number|
next "" if message.empty?
lead = number ? "(#{number}) " : ""
lead = lead.ljust(padding)
message = message.gsub("\n", "\n" + " " * (padding + 2))
"#{lead}#{message}"
end.join("\n")
end
private
def write_line(incompatibility, message, numbered:)
if numbered
number = @line_numbers.length + 1
@line_numbers[incompatibility] = number
end
@lines << [message, number]
end
def visit(incompatibility, conclusion: false)
raise unless incompatibility.conflict?
numbered = conclusion || @derivations[incompatibility] > 1;
conjunction = conclusion || incompatibility == @root ? "So," : "And"
cause = incompatibility.cause
if cause.conflict.conflict? && cause.other.conflict?
conflict_line = @line_numbers[cause.conflict]
other_line = @line_numbers[cause.other]
if conflict_line && other_line
write_line(
incompatibility,
"Because #{cause.conflict} (#{conflict_line})\nand #{cause.other} (#{other_line}),\n#{incompatibility}.",
numbered: numbered
)
elsif conflict_line || other_line
with_line = conflict_line ? cause.conflict : cause.other
without_line = conflict_line ? cause.other : cause.conflict
line = @line_numbers[with_line]
visit(without_line);
write_line(
incompatibility,
"#{conjunction} because #{with_line} (#{line}),\n#{incompatibility}.",
numbered: numbered
)
else
single_line_conflict = single_line?(cause.conflict.cause)
single_line_other = single_line?(cause.other.cause)
if single_line_conflict || single_line_other
first = single_line_other ? cause.conflict : cause.other
second = single_line_other ? cause.other : cause.conflict
visit(first)
visit(second)
write_line(
incompatibility,
"Thus, #{incompatibility}.",
numbered: numbered
)
else
visit(cause.conflict, conclusion: true)
@lines << ["", nil]
visit(cause.other)
write_line(
incompatibility,
"#{conjunction} because #{cause.conflict} (#{@line_numbers[cause.conflict]}),\n#{incompatibility}.",
numbered: numbered
)
end
end
elsif cause.conflict.conflict? || cause.other.conflict?
derived = cause.conflict.conflict? ? cause.conflict : cause.other
ext = cause.conflict.conflict? ? cause.other : cause.conflict
derived_line = @line_numbers[derived]
if derived_line
write_line(
incompatibility,
"Because #{ext}\nand #{derived} (#{derived_line}),\n#{incompatibility}.",
numbered: numbered
)
elsif collapsible?(derived)
derived_cause = derived.cause
if derived_cause.conflict.conflict?
collapsed_derived = derived_cause.conflict
collapsed_ext = derived_cause.other
else
collapsed_derived = derived_cause.other
collapsed_ext = derived_cause.conflict
end
visit(collapsed_derived)
write_line(
incompatibility,
"#{conjunction} because #{collapsed_ext}\nand #{ext},\n#{incompatibility}.",
numbered: numbered
)
else
visit(derived)
write_line(
incompatibility,
"#{conjunction} because #{ext},\n#{incompatibility}.",
numbered: numbered
)
end
else
write_line(
incompatibility,
"Because #{cause.conflict}\nand #{cause.other},\n#{incompatibility}.",
numbered: numbered
)
end
end
def single_line?(cause)
!cause.conflict.conflict? && !cause.other.conflict?
end
def collapsible?(incompatibility)
return false if @derivations[incompatibility] > 1
cause = incompatibility.cause
# If incompatibility is derived from two derived incompatibilities,
# there are too many transitive causes to display concisely.
return false if cause.conflict.conflict? && cause.other.conflict?
# If incompatibility is derived from two external incompatibilities, it
# tends to be confusing to collapse it.
return false unless cause.conflict.conflict? || cause.other.conflict?
# If incompatibility's internal cause is numbered, collapsing it would
# get too noisy.
complex = cause.conflict.conflict? ? cause.conflict : cause.other
!@line_numbers.has_key?(complex)
end
def count_derivations(incompatibility)
if @derivations.has_key?(incompatibility)
@derivations[incompatibility] += 1
else
@derivations[incompatibility] = 1
if incompatibility.conflict?
cause = incompatibility.cause
count_derivations(cause.conflict)
count_derivations(cause.other)
end
end
end
end
end
|
