cli: conditionally output unicode characters in the output of sql -e

[knz]

Summary:

• by default, sql -e always escapes strings that contain special
  characters. It also forcefully escapes strings containing double
  quotes and backslashes, so as to ease automated processing by other
  languages (ie. a string starting with a doublequote character in the
  output will always be the start of an escaped string.). This
  way issue cli: weirdness in SQL shell when printing a row #4315 is still addressed adequately.
• a new flag --pretty is added to the sql sub-command, to print
  row data as pretty-formatted ASCII art tables.
• when results are pretty-formatted (either in the interactive shell
  or with sql --pretty -e), graphic unicode and newline characters
  are printed without escaping. This keeps the fix to cli: printing of strings containing newlines in cli #6926.
• new tests are added in cli_test.go (Example_sql_escape) to test
  escaped and non-escaped output when table and column names contain
  special characters.
• the cli API renames runPrettyQuery to
  runQueryAndFormatResults, and extends it with an extra argument to
  specify pretty-printing.

(See issues/PRs #7045, #6926, #4354 and #4315 for background discussion.)

cc @bdarnell @mjibson @dt

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This change is

[tamird]

Reviewed 12 of 12 files at r1.
Review status: all files reviewed at latest revision, 1 unresolved discussion, all commit checks successful.

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sql/show.go, line 118 [r1] (raw file):

          buf.WriteString(",")
      }
      buf.WriteString("\n\t")

👎 on this - if tablewriter does the wrong thing with tabs, can we report it upstream?

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Comments from Reviewable

[knz]

Review status: all files reviewed at latest revision, 1 unresolved discussion, all commit checks successful.

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sql/show.go, line 118 [r1] (raw file):

Previously, tamird (Tamir Duberstein) wrote…

👎 on this - if tablewriter does the wrong thing with tabs, can we report it upstream?

Done: https://github.com/olekukonko/tablewriter/issues/36 Nevertheless I think the readability improvement still justifies implementing the workaround on our side until the upstream issue is fixed.

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Comments from Reviewable

[tamird]

Review status: all files reviewed at latest revision, 1 unresolved discussion, all commit checks successful.

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sql/show.go, line 118 [r1] (raw file):

Previously, knz (kena) wrote…

Done: olekukonko/tablewriter#36
Nevertheless I think the readability improvement still justifies implementing the workaround on our side until the upstream issue is fixed.

another thought: use [`tabwriter`](https://golang.org/pkg/text/tabwriter/) on the way into the tablewriter to get the right behaviour.

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Comments from Reviewable

[knz]

Review status: all files reviewed at latest revision, 1 unresolved discussion, all commit checks successful.

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sql/show.go, line 118 [r1] (raw file):

Previously, tamird (Tamir Duberstein) wrote…

another thought: use tabwriter on the way into the tablewriter to get the right behaviour.

That was a good idea! I got it to work and thus reverted the change on SHOW CREATE. Thanks for the hint!

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Comments from Reviewable

[tamird]

Previously, knz (kena) wrote…

cli: conditionally output unicode characters in the output of sql -e

Summary:

• by default, sql -e always escapes strings that contain special

  characters. It also forcefully escapes strings containing double

  quotes and backslashes, so as to ease automated processing by other

  languages (ie. a string starting with a doublequote character in the

  output will always be the start of an escaped string.). This

  way issue cli: weirdness in SQL shell when printing a row #4315 is still addressed adequately.

• a new flag --pretty is added to the sql sub-command, to print

  row data as pretty-formatted ASCII art tables.

• when results are pretty-formatted (either in the interactive shell

  or with sql --pretty -e), graphic unicode and newline characters

  are printed without escaping. This keeps the fix to cli: printing of strings containing newlines in cli #6926.

• new tests are added in cli_test.go (Example_sql_escape) to test

  escaped and non-escaped output when table and column names contain

  special characters.

• the cli API renames runPrettyQuery to

  runQueryAndFormatResults, and extends it with an extra argument to

  specify pretty-printing.

(See issues/PRs #7045, #6926, #4354 and #4315 for background discussion.)

cc @bdarnell @mjibson @dt

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Reviewed 4 of 4 files at r2.
Review status: all files reviewed at latest revision, 1 unresolved discussion, some commit checks pending.

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cli/sql_util.go, line 276 [r2] (raw file):

  var buf bytes.Buffer
  w := new(tabwriter.Writer)
  w.Init(&buf, 4, 0, 1, ' ', 0)

nit: https://golang.org/pkg/text/tabwriter/#NewWriter

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Comments from Reviewable

[knz]

TFYR!

Previously, tamird (Tamir Duberstein) wrote…

:lgtm:

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Review status: 9 of 10 files reviewed at latest revision, 1 unresolved discussion, some commit checks pending.

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cli/sql_util.go, line 276 [r2] (raw file):

Previously, tamird (Tamir Duberstein) wrote…

nit: https://golang.org/pkg/text/tabwriter/#NewWriter

Done.

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Comments from Reviewable

[tamird]

Reviewed 1 of 1 files at r3.
Review status: all files reviewed at latest revision, all discussions resolved, some commit checks pending.

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Comments from Reviewable

[bdarnell]

Previously, knz (kena) wrote…

TFYR!

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Review status: all files reviewed at latest revision, all discussions resolved, all commit checks successful.

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Comments from Reviewable

[jseldess]

Docs updated with cockroachdb/docs#373.