The existing implementation of text/template handles the option
"missingkey=error" in an inconsitent manner: If the provided data is
a nil-interface, no error is returned (despite the fact that no key
can be found in it).
This patch makes text/template return an error if "missingkey=error"
is set and the provided data is a not a valid reflect.Value.
Fixes#15356
Change-Id: Ia0a83da48652ecfaf31f18bdbd78cb21dbca1164
Reviewed-on: https://go-review.googlesource.com/31638
Reviewed-by: Rob Pike <r@golang.org>
Run-TryBot: Rob Pike <r@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Instead of scanning the text to count newlines, which is n², keep track as we go
and store the line number in the token.
benchmark old ns/op new ns/op delta
BenchmarkParseLarge-4 1589721293 38783310 -97.56%
Fixes#17851
Change-Id: I231225c61e667535e2ce55cd2facea6d279cc59d
Reviewed-on: https://go-review.googlesource.com/33234
Run-TryBot: Rob Pike <r@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
This reverts commit 794fb71d9c.
Reason for revert: submitted without TryBots and it broke all three race builders.
Change-Id: I80a1e566616f0ee8fa3529d4eeee04268f8a713b
Reviewed-on: https://go-review.googlesource.com/33232
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Instead of scanning the text to count newlines, which is n², keep track as we go
and store the line number in the token.
benchmark old ns/op new ns/op delta
BenchmarkParseLarge-4 1589721293 38783310 -97.56%
Fixes#17851
Change-Id: Ieaf89a35e371b405ad92e38baa1e3fa98d18cfb4
Reviewed-on: https://go-review.googlesource.com/32923
Reviewed-by: Robert Griesemer <gri@golang.org>
CL 31462 made it possible to operate directly on reflect.Values
instead of always forcing a round trip to interface{} and back.
The round trip was losing addressability, which hurt users.
The round trip was also losing "interface-ness", which helped users.
That is, using reflect.ValueOf(v.Interface()) instead of v was doing
an implicit indirect any time v was itself an interface{} value: the result
was the reflect.Value for the underlying concrete value contained in the
interface, not the interface itself.
CL 31462 eliminated some "unnecessary" reflect.Value round trips
in order to preserve addressability, but in doing so it lost this implicit
indirection. This CL adds the indirection back.
It may help to compare the changes in this CL against funcs.go from CL 31462:
https://go-review.googlesource.com/#/c/31462/4/src/text/template/funcs.go
Everywhere CL 31462 changed 'v := reflect.ValueOf(x)' to 'v := x',
this CL changes 'v := x' to 'v := indirectInterface(x)'.
Fixes#17714.
Change-Id: I67cec4eb41fed1d56e1c19f12b0abbd0e59d35a2
Reviewed-on: https://go-review.googlesource.com/33139
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Rob Pike <r@golang.org>
The report in #17414 points out that if you have many many templates,
then this is an overwhelming list and just hurts the signal-to-noise ratio of the error.
Even the test of the old behavior also supports the idea that this is noise:
template: empty: "empty" is an incomplete or empty template; defined templates are: "secondary"
The chance that someone mistyped "secondary" as "empty" is slim at best.
Similarly, the compiler does not augment an error like 'unknown variable x'
by dumping the full list of all the known variables.
For all these reasons, drop the list.
Fixes#17414.
Change-Id: I78f92d2c591df7218385fe723a4abc497913acf8
Reviewed-on: https://go-review.googlesource.com/32116
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rob Pike <r@golang.org>
Add support for passing reflect.Values to and returning reflect.Values from
any registered functions in the FuncMap, much as if they were
interface{} values. Keeping the reflect.Value instead of round-tripping
to interface{} preserves addressability of the value, which is important
for method lookup.
Change index and a few other built-in functions to use reflect.Values,
making a loop using explicit indexing now match the semantics that
range has always had.
Fixes#14916.
Change-Id: Iae1a2fd9bb426886a7fcd9204f30a2d6ad4646ad
Reviewed-on: https://go-review.googlesource.com/31462
Reviewed-by: Rob Pike <r@golang.org>
Return an error message instead of eating memory and eventually
triggering a stack overflow.
Fixes#15618
Change-Id: I3dcf1d669104690a17847a20fbfeb6d7e39e8751
Reviewed-on: https://go-review.googlesource.com/23091
Reviewed-by: Rob Pike <r@golang.org>
When evaluating "{{.MissingField}}" on a nil *T, Exec returns
"can't evaluate field MissingField in type *T" instead of
"nil pointer evaluating *T.MissingField".
Fixesgolang/go#15125
Change-Id: I6e73f61b8a72c694179c1f8cdc808766c90b6f57
Reviewed-on: https://go-review.googlesource.com/21705
Reviewed-by: Rob Pike <r@golang.org>
Read what a non-empty interface points to.
The deleted lines were added in https://codereview.appspot.com/4810060/,
which attempted to break an infinite loop. That was a long time ago.
If I just delete these lines with current codebase, the test "bug1"
(added in that CL) does not fail.
All new tests fail without this fix.
Fixes#12924
Change-Id: I9370ca44facd6af3019850aa065b936e5a482d37
Reviewed-on: https://go-review.googlesource.com/15809
Reviewed-by: Andrew Gerrand <adg@golang.org>
This change adds a new "block" keyword that permits the definition
of templates inline inside existing templates, and loosens the
restriction on template redefinition. Templates may now be redefined,
but in the html/template package they may only be redefined before
the template is executed (and therefore escaped).
The intention is that such inline templates can be redefined by
subsequent template definitions, permitting a kind of template
"inheritance" or "overlay". (See the example for details.)
Fixes#3812
Change-Id: I733cb5332c1c201c235f759cc64333462e70dc27
Reviewed-on: https://go-review.googlesource.com/14005
Reviewed-by: Rob Pike <r@golang.org>
There was no verification in Funcs that the map had valid names,
which meant that the error could only be caught when parsing
the template that tried to use them. Fix this by validating the names
in Funcs and panicking before parsing if there is a bad name.
This is arguably an API change, since it didn't trigger a panic
before, but Funcs did already panic if the function itself was no
good, so I argue it's an acceptable change to add more sanity
checks.
Fixes#9685.
Change-Id: Iabf1d0602c49d830f3ed71ca1ccc7eb9a5521ff5
Reviewed-on: https://go-review.googlesource.com/14562
Reviewed-by: Andrew Gerrand <adg@golang.org>
Check reflect.Value.IsValid() before calling other reflect.Value methods
that panic on zero values.
Added tests for cases with untyped nils. They panicked without these fixes.
Removed a TODO.
Fixes#12356
Change-Id: I9b5cbed26db09a0a7c36d99a93f8b9729899d51e
Reviewed-on: https://go-review.googlesource.com/14340
Reviewed-by: Rob Pike <r@golang.org>
Borrowing a suggestion from the issue listed below, we modify the lexer to
trim spaces at the beginning (end) of a block of text if the action immediately
before (after) is marked with a minus sign. To avoid parsing/lexing ambiguity,
we require an ASCII space between the minus sign and the rest of the action.
Thus:
{{23 -}}
<
{{- 45}}
produces the output
23<45
All the work is done in the lexer. The modification is invisible to the parser
or any outside package (except I guess for noticing some gaps in the input
if one tracks error positions). Thus it slips in without worry in text/template
and html/template both.
Fixes long-requested issue #9969.
Change-Id: I3774be650bfa6370cb993d0899aa669c211de7b2
Reviewed-on: https://go-review.googlesource.com/14391
Reviewed-by: Andrew Gerrand <adg@golang.org>
Executing a template involving variadic functions featuring
a []interface{} slice (such as printf) could result in a
panic in reflect.Value.Call, due to incorrect type checking.
The following expressions failed (with a panic):
{{true|printf}}
{{1|printf}}
{{1.1|printf}}
{{'x'|printf}}
{{1+2i|printf}}
Implemented proper type checks for the fixed parameters of the
variadic functions.
Fixes#10946
Change-Id: Ia75333f651f73b3d2e024cb0c47cc30d90cb6852
Reviewed-on: https://go-review.googlesource.com/10403
Reviewed-by: Rob Pike <r@golang.org>
Missed a case; just need to call validateType.
Fixes#10800.
Change-Id: I81997ca7a9feb1be31c8b47e631b32712d7ffb86
Reviewed-on: https://go-review.googlesource.com/10031
Reviewed-by: Andrew Gerrand <adg@golang.org>
The current parser ignores obvious errors such as:
{{0.1.E}}
{{true.any}}
{{"hello".wrong}}
{{nil.E}}
The common problem is that a chain is built from
a literal value. It then panics at execution time.
Furthermore, a double dot triggers the same behavior:
{{..E}}
Addresses a TODO left in Tree.operand to catch these
errors at parsing time.
Note that identifiers can include a '.', and pipelines
could return an object which a field can be derived
from (like a variable), so they are excluded from the check.
Fixes#10615
Change-Id: I903706d1c17861b5a8354632c291e73c9c0bc4e1
Reviewed-on: https://go-review.googlesource.com/9621
Reviewed-by: Rob Pike <r@golang.org>
This was disallowed for error-checking reasons but people ask for
it, it's easy, and it's clear what it all means.
Fixes#7323.
Change-Id: I26542f5ac6519e45b335ad789713a4d9e356279b
Reviewed-on: https://go-review.googlesource.com/9537
Reviewed-by: Russ Cox <rsc@golang.org>
Add one option, which is the motivating example, a way to control
what happens when a map is indexed with a key that is not in the map.
Rather than do something specific for that case, we provide a simple
general option mechanism to avoid adding API if something else
comes up. This general approach also makes it easy for html/template
to track (and adapt, should that become important).
New method: Option(option string...). The option strings are key=value
pairs or just simple strings (no =).
New option:
missingkey: Control the behavior during execution if a map is
indexed with a key that is not present in the map.
"missingkey=default" or "missingkey=invalid"
The default behavior: Do nothing and continue execution.
If printed, the result of the index operation is the string
"<no value>".
"missingkey=zero"
The operation returns the zero value for the map type's element.
"missingkey=error"
Execution stops immediately with an error.
Fixes#6288.
Change-Id: Id811e2b99dc05aff324d517faac113ef3c25293a
Reviewed-on: https://go-review.googlesource.com/8462
Reviewed-by: Robert Griesemer <gri@golang.org>
An explicit nil in an expression like nil.Foo caused a panic
because the evaluator attempted to reflect on the nil.
A typeless nil like this cannot be used to do anything, so
just error out.
Fixes#9426
Change-Id: Icd2c9c7533dda742748bf161eced163991a12f54
Reviewed-on: https://go-review.googlesource.com/7643
Reviewed-by: David Symonds <dsymonds@golang.org>
Simple bug in argument processing: The final arg may
be the pipeline value, in which case it gets bound to the
fixed argument section. The code got that wrong. Easy
to fix.
Fixes#8950.
LGTM=bradfitz
R=golang-codereviews, bradfitz
CC=golang-codereviews
https://golang.org/cl/161750043
Was just a missing case (literally) in the type checker.
Fixes#8473.
LGTM=adg
R=golang-codereviews, adg
CC=golang-codereviews
https://golang.org/cl/142460043
Previously, signed and unsigned integers could not be compared, but
this has problems with things like comparing 'x' with a byte in a string.
Since signed and unsigned integers have a well-defined ordering,
even though their types are different, and since we already allow
comparison regardless of the size of the integers, why not allow it
regardless of the sign?
Integers only, a fine place to draw the line.
Fixes#7489.
LGTM=adg
R=golang-codereviews, adg
CC=golang-codereviews
https://golang.org/cl/149780043
Özgür Kesim
Rob Pike
Brad Fitzpatrick
Russ Cox
Josh Bleecher Snyder
Andrew Gerrand
Nodir Turakulov
Didier Spezia